introduction to heredity curriculum final
DESCRIPTION
Detail plan of action of the unitTRANSCRIPT
Unit Overview
Five easy-to-implement classroom activities teach the basics of heritable
traits. Three take-home activities help students share what they're learning
with their families.
Learning Objectives
Traits are observable characteristics
that are passed from parent to child.
An individual will have many traits in
common with others and more so with
siblings and parents.
An individual's overall combination of
traits makes them unique.
Some traits are more common in a
population than others.
An equal number of traits are passed
from each parent.
DNA is a set of instructions that
specifies the traits of an organism.
Variations in DNA lead to the inheritance of different traits.
Suggested Implementation
Below is a suggested sequence for implementing the activities contained in
the unit. Please see each individual activity for implementation instructions,
suggestions for adaptations and extensions, and applicable standards.
Time Required
approx. 120 mins
Grade Band
8-10
Prior Knowledge Needed
None
Targeted Standards
CBSE: Life Science; Reproduction and
Heredity AAAS Benchmarks: The Living
Environment: Heredity
Introduction to Heredity
Lesson Plans
An Inventory of My Traits
A Tree of Genetic Traits
Generations of Traits
Traits Bingo
A Recipe for Traits
Take-Home Activities
Family Traits Trivia
Handy Family Tree
Family Traits & Traditions
Teacher Resources
Inherited Traits:
A Quick Reference
Sample Parent Letter (doc)
Note About PTC Safety
UNIT CONTENT
DAY Activity Notes Day 1 (40 mins.)
An Inventory of My Traits Students take an inventory of their own easily-observable genetic traits and compare those inventories with other students in groups.
Observable Traits slideshow (Teacher Reference)
This click-through slideshow shows many of the traits included in An Inventory of My Traits.
A Tree of Genetic Traits Students find the most and least common combination of traits in the class by marking their traits for tongue rolling, earlobe attachment, and PTC tasting on paper leaf cut-outs. Students then organize the leaves on a large "tree of traits."
Family Traits Trivia (Homework)
Students use game cards to inventory the traits in their family. (Note: individuals in families do not need to be related to participate in this activity.)
Day 2 (40 mins.)
Generations of Traits Students track and record the passage of colored "pom-pom traits" through three generations of ginger-bread people.
Traits Bingo In this review activity, students cross off or color bingo squares in response to questions about their traits.
Handy Family Tree (Homework)
Students distinguish between inherited and learned traits by creating a "family tree of traits" using handprints. (Note: Individuals in families do not need to be related to participate in this activity.)
Day 3 (40 mins.)
A Recipe for Traits Students learn that differences in DNA lead to different traits by: 1) randomly choosing strips of paper that represent DNA, then 2) decoding the DNA strips to complete a drawing of a dog.
Family Traits and Traditions (Homework)
Students and their families play a matching game with cards to identify traits that are inherited and traits that are learned or passed on through tradition.
Every organism inherits a unique combination of traits.
DNA is a set of instructions that specifies the traits of an organism.
Information in the DNA molecule is divided into segments (called genes).
Variations in the DNA lead to the inheritance of different traits.
Copy masters for preparing colored DNA strips having fun symbols to represent information about traits.
A dog traits key that allows participants to decode their DNA recipe and visualize how traits are specified.
Special Features You’ll Find Inside
Activity Time:40 minutes
30 minutes to review activity, make copies, and prepare dog DNA strips
Prep Time:
Logistics
Time Required
Copies of participant pages, drawing paper, crayons or colored pencils, tape, envelopes, and colored paper (4 different colors needed)
Traits are heritable characteristics.
Materials
Prior Knowledge Needed
Participants create and decode a “DNA recipe” for man’s best friend to observe how variations in DNA lead to the inheritance of different traits. Strips of paper (representing DNA) are randomly selected and used to assemble a DNA molecule. Participants read the DNA recipe to create a drawing of their pet, and compare it with others in the group to note similarities and differences.
Activty OverviewLearning Objectives
A Recipe for Traits
R.V.Raghavendra Rao, PGT Biology, Vizianagaram A.P.
R.V.Raghavendra Rao, PGT Biology, Vizianagaram A.P.
“Dog DNA” envelopes:
1. To prepare 14 envelopes, make four copies each of DNA Strips A, B, C, and D (pages 4-7) on colored paper. Choose one color for each type of DNA Strip. For example:
DNA Strips A (page 5) 4 copies on Blue DNA Strips B (page 6) 4 copies on Green DNA Strips C (page 7) 4 copies on Yellow DNA Strips D (page 8) 4 copies on Red
2. Cut out the DNA strips on each page (a paper-cutter works well).
3. Place two DNA strips of each color into an envelope. The envelope should contain eight DNA strips total (four different colors).
4. Repeat step three until you have assembled 14 “Dog DNA” envelopes.
Note: Eight is the minimum number of DNA strips per envelope that you need to carry out the activity. Adding more DNA strips of each color increases the variety of possibilities for each trait.
Activity Instructions
Display different types of instructions (e.g. a recipe book, a blueprint, a DNA molecule). Ask participants •
what they might use these instructions for. Explain that just as a recipe is used to cook a meal or a blueprint is used to build a home, DNA contains instructions that specify an organism’s traits.
Read the beginning paragraph of • A Recipe for Traits (page P-1) as a group. You may want to show a completed DNA “recipe” and point out the different segments (representing genes) as well as the 4 symbols (representing the 4 chemical bases A, C, G and T) that make up the DNA alphabet in this activity.
Review the instructions on page P-1. You may want to demonstrate how to use the • Dog Traits Key (see page P-2 to P-3). Read the DNA recipe and identify the first trait.
Remind participants to leave the DNA strips they choose out of the envelope and tape them together • in order. The resulting long strand will be their DNA recipe.
Have participants work individually or in pairs to complete the activity. Wh• en participants have finished, have them post their dog drawings on the wall along with the DNA recipe for their dog.
Are any two dogs alike? Point out that every dog shares some traits in common with others, but each has an •
overall combination of traits that is unique.
Explain that variations in each DNA strand (the sequence of symbols) led to the inheritance of different traits. •
One copy of pages P-1 to P-3
One envelope containing “Dog DNA” (see instructions at left)
Crayons or colored pencils, drawing paper, tape
QuantitiesPer Participant or Pair
Preparation
A Recipe for Traits
1
2013 Heredity R.V.Raghavendra Rao, PGT Biology, Vizianagaram A.P. 1
Information in a DNA strand (or molecule) is grouped into small segments called genes (represented here by •
colored DNA strips).
A single DNA strand is often referred to as a chromosome. In this example, the dog had one chromosome •
containing 8 genes. (Humans have 23 pairs of chromosomes containing over 22,000 genes!)
The DNA molecule contains a sequence of four chemical bases • (represented here by four symbols). Each base is referred to by the first letter of its name: Adenine (A), Cytosine (C), Guanine (G) and Thymine (T). The sequence of these chemical bases encodes a detailed set of instructions for building an organism’s traits. (The human genome contains approximately 3 billion pairs or bases!)
Participants were asked to assemble their DNA strips in the order they were drawn. This is because all •
individuals of a species have the same genes in the same order along their chromosomes. (This is what allows researchers to “map” the location of a gene to a specific place on a chromosome.) It is the small sequence variations within each gene that lead to differences in traits.
There is usually a limited number of sequence variations for a gene. That is, a gene usually comes in a few •
different forms or flavors (called “alleles”). There was a possibility of four different flavors or alleles for each of the dog genes in this activity.
In this activity, a single gene determined each dog trait. More often a trait is influenced by more than one •
gene as well as environmental factors.
As a group, make a “map” of the dog genome. Compare the different DNA recipes hanging up in the room. •
Point out that the gene for body shape is always at the top of the DNA molecule (or chromosome), the gene for head shape is always second, and so on. Draw a representation of a chromosome having 8 segments. Have participants come up with a creative name for each gene. Label the segments with the gene names, and specify the trait they encode. Point out that although each dog looks differently (has a different combination of traits), it is still possible to make a general map of the dog genome.
Show participants a completed map of the human genome (e.g., the Human Genome Landmarks Poster •
or its web companion) and discuss how researchers have mapped the 22,000 plus genes to particular locations on the 23 pairs of human chromosomes. To order a free copy of this poster or view it online, check out the web site developed by the U.S. Department of Energy’s Human Genome Management Information System (HGMIS).
Discussion Points
Extension
A Recipe for Traits
R.V.Raghavendra Rao, PGT Biology, Vizianagaram A.P.
R.V.Raghavendra Rao, PGT Biology, Vizianagaram A.P. 2
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A Recipe for Traits
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A Recipe for Traits
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A Recipe for Traits
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A Recipe for Traits
7 R.V.Raghavendra Rao, PGT Biology, Vizianagaram A.P.
Follow the directions below to create a DNA recipe for a dog. Using the Dog Traits Key, read your DNA recipe and make a drawing of your dog showing all of its traits.
Directions:1. Make sure you have an envelope containing “Dog DNA”.2. Determine the first trait of your dog (body shape) by randomly picking a
piece of dog DNA out of the envelope.3. Look at the symbols on the DNA strip you have chosen. Match the pattern to
one you see on the Dog Traits Key for body shape. 4. Circle the picture for body shape that matches the DNA piece that you
picked. 5. Set the piece of DNA aside and repeat steps 1-4 for the next trait on the key.6. After circling the matching picture, tape the second piece of DNA to the first
to make one long strand. This will become the DNA recipe for your entire dog.
7. Repeat these steps for each of the traits listed on the Dog Traits Key. 8. When you have finished, draw your dog with all of its traits (the traits you
have circled on the Dog Traits Key) on a separate piece of paper. 9. Hang up the picture of your dog along with its DNA recipe (the DNA pieces
you chose attached in a long strand).
Is your dog different from or the same as others in the group?
A Recipe for TraitsA set of instructions called DNA makes a “recipe” for traits in all organisms. Information in a DNA strand is grouped into small segments. Each segment is made of even smaller units (like recipes are made of words, and words are made of letters). Differences in the DNA “alphabet” are what make differences in traits (just like a different sequence of letters makes different words, and a different recipe).
R.V.Raghavendra Rao, PGT Biology, Vizianagaram A.P.
Body Shape
Head Shape
Ears
Legs
Do
g T
rait
s K
ey
Small, Thin, Long, Straight
Large, Thin, Long, Tapered
Meduium, Very Muscular, Short
Large Semi-Muscular, Straight
Long, Thin Flat Short Droopy
Small, Pointy Big Droopy Medium Square Medium Droopy
Long, Thin Short, Stubby Medium Stocky, Muscular
R.V.Raghavendra Rao, PGT Biology, Vizianagaram A.P.
Eyes
Tail
Coat Color
Hair
Dark Brown Light Brown Blue Green
Short Nub Long with Short Hair
Pompon Tipped Long and Bushy
Brown Black Red-Brown Yellow
Curly, Short Straight, Short Straight, Long Wavy, Long
Do
g T
rait
s K
ey
R.V.Raghavendra Rao, PGT Biology, Vizianagaram A.P.
A Tree of Genetic Traits
Traits are observable characteristics that are passed down from parent to child.
An individual will have many traits they share in common with others.
An individual’s overall combination of traits makes them unique.
Some traits are more common in a population than others.
Activity Time:30 minutes
30 minutes to review activity, make copies of tree leaf cut-outs, and prepare traits tree
Prep Time:
Logistics
Time Required
PTC paper, hard candies, leaf cut-outs, tape, scissors, transparencies or large butcher paper
None
Materials
Prior Knowledge Needed
Participants mark their traits for tongue rolling, PTC tasting (a harmless, bitter chemical), and earlobe attachment on tree leaf cut-outs. They then place their leaves on a large tree whose branches each represent a different combination of traits. When completed, the tree forms a visual representation of the frequency of trait combinations within the group.
Activity Overview Learning Objectives
1
A Tree of Genetic Traits
Provide each participant with a leaf and instruct them to cut it out. •
Explain that traits are observable characteristics we inherit from our •
parents. Demonstrate the tongue rolling and earlobe attachment traits. Have participants mark “yes” or “no” on their leaf for these traits as appropriate.
Hand out PTC paper. Instruct participants to place a piece of PTC paper on the tip of their tongue to see •
if they can taste anything. The chemical tastes bitter to those who can taste it. For those who cannot taste PTC, the paper has no taste.
Note• : PTC paper is inexpensive and can be purchased from Sargent Welch (www.sargentwelch.com), Carolina Math and Science (www.carolina.com) or Ward’s Natural Science (http://www.wardsci.com).
Instruct participants to check “yes” or “no” on their leaves for PTC tasting. • Hand out a hard candy to each participant to neutralize the taste of the PTC.
Demonstrate how to determine where to place the leaves on the Trait Tree starting at the base of the •
branches and working your way out toward the tips.
Call participants up in groups to place their leaves on •
the appropriate branches. The leaves will be clustered around the branch representing the most common combination of traits in the group. Some branches of the tree will remain relatively sparse.
Optional:• Make leaf cut-outs in two different colors, one for males and one for females, to track combinations of traits within the different genders.
Optional:• Increase your data pool by including additional groups in the exercise, taping all leaves to one tree.
Activity Instructions
Common MisconceptionA widespread misconception is that all traits exhibit either a dominant or recessive pattern of inheritance. But these terms only apply to single gene traits. The traits included in this activity are part of the small number that may be due to only one or two genes. However, most human genetic traits are influenced by several genes as well as interactions with the environment. The inheritance of complex traits is difficult to predict, and does not follow typical dominant or recessive patterns.
One leaf cut-out, hard candy, piece of PTC paper
Scissors, pen or pencil
Tape
Quantities
Per Group of 2
Per Participant
Whole Group
• Copy the Genetic Traits Tree graphic provided on page 4 (or page 6 for Telugu speaking audiences) onto an overhead transparency. Use an overhead projector to project the transparency large onto a blank wall. Alternatively, draw a large tree on butcher paper based on page 4. Post it in an easily accessible and visible area of the room.
2
A Tree of Genetic Traits
Some traits are more common in a population than others. What is the most common combination of traits •
in the group? What is the least common combination of traits in the group?
Every person has a unique combination of traits. If we were to look at more traits than three, we would •
eventually need a branch on the Trait Tree for each person in the group.
Discussion Points
3
A Tree of Genetic TraitsLeaf Cut-outsAn Inventory of My Traits: Leaf Cut-Outs
PTC Tasting
Tongue Rolling
EarlobesAttached Free
Yes No
Yes No
PTC Tasting
Tongue Rolling
EarlobesAttached Free
Yes No
Yes No
PTC Tasting
Tongue Rolling
EarlobesAttached Free
Yes No
Yes No
PTC Tasting
Tongue Rolling
EarlobesAttached Free
Yes No
Yes No
PTC Tasting
Tongue Rolling
EarlobesAttached Free
Yes No
Yes No
PTC Tasting
Tongue Rolling
EarlobesAttached Free
Yes No
Yes No
PTC Tasting
Tongue Rolling
EarlobesAttached Free
Yes No
Yes No
PTC Tasting
Tongue Rolling
EarlobesAttached Free
Yes No
Yes No
4
A Tree of Genetic TraitsExample Trait Tree
Attached Earlobes Free
Earlobes
PTCTaster Non-PTC
TasterTongue Roller
Non-PTCTaster
PTCTaster
Tongue Roller
Tongue Roller
Tongue Roller
Non-Tongue Roller
Non-Tongue Roller
Non-Tongue Roller
Non-Tongue Roller
Materials needed
Instructions
1 2
1
Handy Family Tree
Trace the right and left hand of each family member onto a piece of colored paper
One large piece of paper or poster •
board
Colored paper (one or two for each •
person)
Scissors•
Pens or markers•
Tape or glue•
Cut out the handprints
Inherited traits are physical characteristics that can be passed down from parent to child. Learned traits are acquired through interactions with the environment. This activity can help you learn to distinguish between inherited and learned traits.
A family tree is a picture that shows members of your family. It can include information about each person. Do this activity to create your own family tree. Include fun facts about each family member on their very own handprint!
Did You Know?
Optional
Trait no one else in your family has
Trait shared with a brother or sister
Trait shared with a parent
Trait shared with a grandparent
Word describing your character
Favorite game, sport or hobby
Favorite school subject
Favorite food
3
4
5
2
Draw a tree trunk onto a large piece of paper or poster board.
On each finger of your left handprint list a trait (physical characteristic) that you have inherited such as:
eye color•
hair color•
dimples•
freckles•
chin shape (smooth or cleft)•
ability to roll the tongue•
earlobe attachment (attached or free)•
hairline shape on the forehead (smooth or pointed)•
Add a small picture of each family member to the palm of one handprint. •
Write their name, date of birth, and place of birth on the palm of the other handprint.
Include handprint shapes for family members who were not available •
to draw their hands. See how your parents’ or grandparents’ favorites compare to yours!
Glue or tape your family’s handprints above the trunk to form a tree. Place the oldest person’s pair of hands at the bottom. Work upward until you place the youngest person’s pair of hands at the top.
On each finger of your right handprint, list a trait that you have acquired or learned. See suggestions above.
Photos of common heritable traits and accompanying background information.
Special Features You’ll Find Inside
Inherited Human Traits: A Quick Reference
Inherited Human Traits: A Quick Reference
Background information about genes, traits and inheritance that supports the activities included in the Heredity & Traits section of the Learn.Genetics website. Includes a pictorial reference of inherited human traits, along with inheritance patterns, frequencies and other interesting facts about each.
Activity Overview
1
Background InformationPhysical traits are observable characteristics determined by specific segments of DNA called genes. Multiple genes are grouped together to form chromosomes, which reside in the nucleus of the cell. Every cell (except eggs and sperm) in an individual’s body contains two copies of each gene. This is due to the fact that both mother and father contribute a copy at the time of conception. This original genetic material is copied each time a cell divides so that all cells contain the same DNA. Genes store the information needed for the cell to assemble proteins, which eventually yield specific physical traits.
Most genes have two or more variations, called alleles. For example, the gene for hairline shape has two alleles – widow’s peak or straight. An individual may inherit two identical or two different alleles from their parents. When two different alleles are present they interact in specific ways. For the traits included in this activity, the alleles interact in what is called a dominant or a recessive manner. The traits due to dominant alleles are always observed, even when a recessive allele is present. Traits due to recessive alleles are only observed when two recessive alleles are present. For example, the allele for widow’s peak is dominant and the allele for straight hairline is recessive.
If an individual inherits:
• Two widow’s peak alleles (both dominant), their hairline will have a peak
• One widow’s peak allele (dominant) and one straight hairline allele (recessive), they will have a widow’s peak
• Two straight hairline alleles (recessive), their hairline will be straight.
A widespread misconception is that traits due to dominant alleles are the most common in the population. While this is sometimes true, it is not always the case. For example, the allele for Huntington’s Disease is dominant, while the allele for not developing this disorder is recessive. At most, only 1 in 20,000 people will get Huntington’s; most people have two recessive, normal alleles.
While a few traits are due to only one gene (and its alleles), most genetic traits are the product of interactions between several genes. When more than one gene influences a trait, the inheritance pattern is not easily predictable. The predictable patterns referred to as dominant and recessive apply only to single gene traits.
The traits listed on the next pages have commonly been presented as being determined by single genes. However, it is possible that some may involve more than one gene. When research studies have disagreed on the inheritance pattern for a trait, it has been noted below.
W = dominant widow's peak allellew = recessive straight hairline allele
WW =
Ww =
ww =
Results of Allele Combinations:
Widow's Peak Trait
Widow's Peak Trait
Straight Hairline Trait
Figure 1: Inheritance Patterns of the Widow's Peak Trait
Inherited Human Traits: A Quick Reference
1
Earlobe Attachment
Attached Earlobes Detached Earlobes
If earlobes hang free, they are detached. If they attach directly to the side of the head, they are attached earlobes.
Some scientists have reported that this trait is due to a single gene for which unattached earlobes is dominant and attached earlobes is recessive. Other scientists have reported that this trait is probably due to several genes.
The size and appearance of the lobes are also inherited traits.
Tongue RollingIn 1940, the famous geneticist Alfred Sturtevant noted that about 70% of people of European ancestry are able to roll up the lateral edges of the tongue, while the remaining 30% were unable to do so.
Tongue rolling ability may be due to a single gene with the ability to roll the tongue a dominant trait and the lack of tongue rolling ability a recessive trait. However, there is some
question about the inheritance of tongue rolling. Recent studies have shown that around 30% of identical twins do not share the trait.
Cleft ChinThis trait is reportedly due to a single gene with a cleft chin dominant and a smooth chin recessive.
DimplesDimples are reportedly due to a single gene with dimples dominant (people may exhibit a dimple on only one side of the face) and a lack of dimples recessive.
HandednessSome scientists have reported that handedness is due to a single gene with right handedness dominant and left handedness recessive. However, other scientists have reported that the interaction of two genes is responsible for this trait.
Inherited Human Traits: A Quick Reference
2
Can Roll Tongue Can’t Roll Tongue
FrecklesThis trait is reportedly due to a single gene; the presence of freckles is dominant, the absence of freckles is recessive1.
Naturally Curly HairEarly geneticists reported that curly hair was dominant and straight hair was recessive. More recent studies suggest that more than one gene may be involved.
AllergiesWhile allergic reactions are induced by things a person comes in contact with, such as dust, particular foods, and pollen, the tendency to have allergies is inherited. If a parent has allergies, there is a one in four (25%) chance that their child will also have allergy problems. This risk increases if both parents have allergies2.
Hand ClaspingFold your hands together by interlocking your fingers without thinking about it. Which thumb is on top – your left or your right?
One study found that 55% of people place their left thumb on top, 45% place their right thumb on top and 1% have no preference.
A study of identical twins concluded that hand clasping has at least some genetic component. However, other scientists have not found evidence that genetics plays a significant role in determining this trait.
ColorblindnessColorblindness is due to a recessive allele located on the X chromosome. Women have two X chromosomes, one of which usually carries the allele for normal color vision. Therefore, few women are colorblind. Men only have one X chromosome, so if they carry the allele for colorblindness, they will exhibit this trait. Thus, colorblindness is seen more frequently in men than in women.
Inherited Human Traits: A Quick Reference
3
Cross Left Thumb Over Right Cross Right Thumb Over Left
Hairline shape is reportedly due to a single gene with a widow’s peak dominant and a straight hairline recessive.
Widow’s Peak Hairline Straight Hairline
Hairline Shape
PTC TastingFor some people the chemical PTC (phenylthiocarbamide) tastes very bitter. For others, it is tasteless.
The ability to taste PTC shows dominant inheritance and is controlled by a gene on chromosomes 7. This gene codes for part of the bitter taste receptor in tongue cells. One of its five alleles (forms) causes a lack of ability to sense bitter tastes; the other four alleles produce intermediate to fully sensitive taste abilities. Approximately 75% of people can taste PTC while the remaining 25% cannot.
PTC-like chemicals are found in the Brassica family of vegetables, such as cabbage, brussels sprouts, and broccoli. People who can taste PTC often do not enjoy eating these vegetables, since they taste bitter to them. Non-tasters tend not to notice bitter tastes and therefore may be more likely to become addicted to nicotine (which is bitter).
PTC-tasting ability has also provided information related to human evolution. Populations in Sub-Sahara Africa, and people who are descended from this area, contain at least five forms of the gene. Some of these forms confer a PTC-tasting ability that is intermediate between taster and non-taster. However, with only a few exceptions, only two forms – taster and non-taster – are found in populations outside of Africa and their descendents. This is consistent with the out-of-Africa hypothesis of modern human origins.
Some scientists think that tasters have fewer cavities, suggesting that there might be a substance in the saliva of tasters that inhibits the bacteria that cause cavities to form. Others think that PTC tasting may be in some way connected with thyroid function.
PTC tasting was a chance discovery in 1931.
Inherited Human Traits: A Quick Reference
4
Does Not Taste PTC Tastes PTC
Pick the Risk: The Polygenic Pedigree Challenge
Activity Time:30 - 45 minutes 30 minutes
Prep Time:
Logistics
Time Required
Copies of participant pages, colored pencils or crayons, disposable cups, colored pom poms
Genes are passed from parents to offspring and contribute to observable physical characteristics. Pedigrees are used to track genetic information.
Materials
Prior Knowledge Needed
Participants are challenged to track and record the passage of colored pom poms (representing genes) through generations of a family using a pedigree. Participants learn that common chronic diseases (such as heart disease) run in families and are caused by the combined action of multiple genes.
Activity OverviewAn inherited trait can be determined by one or by many genes.
All humans have the same genes, but each inherits slightly different forms or “flavors” of each gene.
Many common diseases (such as heart disease) run in families and have a genetic component.
Most common diseases are caused by the combined action of multiple genes and environmental factors.
An individual’s risk of developing a common disease is estimated by looking at siblings, parents and grandparents in a family medical history.
Learning Objectives
1
Pick the Risk: The Polygenic Pedigree Challenge
To engage participants in this topic:
• Compare the prevalence of rare genetic disorders caused by a single gene such as cystic fibrosis (1 in 10,000) with the prevalence of more common diseases such as heart disease (1 in 3).
• Ask the participants: Do common diseases like heart disease, diabetes, or colon cancer have a genetic component?
• Explain that most common diseases do have a genetic component and tend to run in families. However, common diseases differ from rare genetic disorders in that they are usually not caused by defects in a single gene. Rather, they result from the combined effects of multiple genes and environmental factors. Thus, they are called multifactorial diseases.
• Explain that because more than one gene is involved in most common diseases, the inheritance of a common disease is not predictable.
• Information found in a family health history and recorded on a pedigree is used to estimate an individual’s genetic risk (low, medium, or high) of developing a common disease.
Begin activity:
• Explain that the following activity will explore how common “polygenic” diseases (in this case, heart disease) are inherited.
• Invite participants to find a partner with whom they will work to complete the activity; pass out the participant pages and other materials.
• Review the symbols and structure used for a pedigree:
Instructions
One copy of participant pages
2 - 3 disposable cups
Colored pencils or crayons
Colored pom poms (5 different colors: at least 10 red, 2 yellow, 1 each of orange, green, blue)
QuantitiesPer Group of 2
Generation I
Grandmother
Children listed in birth order
This line connects parents and their children.
= Female
= Male
This line connects a male/female couple.
Oldest Youngest
Grandfather
Grandchildren
Generation II
Generation III
2
Pick the Risk: The Polygenic Pedigree Challenge
• Invite participants to begin by following the instructions found on pages P-1 and P-2; each pair of participants should complete the pedigree analysis and answer the questions that follow.
Group discussion:
• Point out that this activity differs from reality in the following ways:
» The number of genes contributing to a polygenic disease is usually not known.
» The number of genes carried by parents or offspring that can increase heart disease risk is not known.
» Environmental factors can also vary an individual’s risk of developing multifactorial diseases.
• Discuss the following questions as a group, comparing and contrasting the Pedigree results obtained by each pair:
» The grandfather in this family was a “high risk” individual. How many of his children were either medium or high risk individuals? How many of his grandchildren were either medium or high risk individuals? (Answers will vary.)
» Did the number of “medium risk” and “high risk” individuals decrease or increase over subsequent generations? Why do you think that happened? (Answer: Decrease. Risk of inheriting heart disease from an affected individual (suchas a grandparent) decreases through the generations because it is unlikely that all of the necessary risk factors [genes] will be passed down to less closely related family members.)
» In this activity you were able to label family members as having a low, medium or high risk of developing heart disease. In reality, do you think it might be difficult to predict an individual’s risk of developing heart disease? Why? (Answer: An individual’s risk of developing heart disease IS difficult to predict because of the reasons outlined under the first group discussion point.)
» If a parent is diagnosed with heart disease, does that mean the children will have it also? Defend your answer. (Be sure to include the key word “risk” in your answer.) (Answer: Not necessarily. But because heart disease does have a genetic component, children of an affected parent have an increased risk of developing heart disease relative to the population at large.)
• Emphasize that these are a few of the reasons why heart disease and other common diseases are so complex, and why the inheritance pattern for such diseases are difficult to predict.
• Therefore, individuals are placed in general categories (high, medium, or low risk groups) based on features from their family health history that correlate with a certain probability of developing a disease.
» For example, it is said that an individual who has a parent (or possibly a grandparent) with heart disease may be “at risk” and should take steps to protect themselves.
• Describe the important features to identify in a family health history (see chart at http://learn.genetics.utah.edu/units/health), including what is meant by a “close” relative.
Common MisconceptionParticipants may think that all heritable traits (and genetic disorders) are caused by a single gene and exhibit dominant or recessive patterns of inheritance. But more commonly, traits result from the combined action of many genes and environmental factors. Such multifactorial traits can exhibit varied and complex patterns of inheritance that are not easy to predict.
3
Pick the Risk: The Polygenic Pedigree Challenge
» Siblings, parents, and possibly grandparents, are informative when assessing an individual’s risk of developing a common disease and need be included in a family health history. It is unlikely that all of the same risk factors (genes) will be present in less closely related family members.
• Discuss why each feature in the chart indicates an individual may be at increased risk for developing heart disease.
» Each feature indicates that the family has accumulated more risk factors (genetic or environmental). Therefore, an individual in this family is more likely to develop disease.
• Discuss behaviors and choices that can reduce an individual’s risk of developing heart disease.
• Conclude the discussion by reminding participants that genetic susceptibility does not mean an individual will inevitably inherit a disease. Positive lifestyle changes and healthy living can reduce genetic risk dramatically. That is why it is so important to know your family health history. If you know you are “at risk” you can take steps to protect yourself.
Learn MoreVisit the elearning bio website to get more great resources like this one!
Risk Continuum
Diagrams to help set up the demonstration.
People can be assigned to a risk group for developing heart and other diseases based on family history/genetics.
Lifestyle choices can positively or negatively influence the risk of developing heart disease.
A higher risk means a greater chance of developing heart disease, not an inevitability of developing it.
Though a lower risk means there is a reduced chance, it is still possible for members of this risk group to develop heart disease.
Special Features You’ll Find Inside
Logistics
Activity Time:
Prep Time:
Time Required
Paper
None
Materials
Prior Knowledge Needed
A group kinesthetic demonstration of what it means to be in a “risk group” for developing heart disease based on family history/genetics.
Activity Overview Learning Objectives
15 minutes
10 minutes
Risk Continuum
Activity Instructions
Participant ActionStarting with the participant most at risk (left) 1. have each person choose a Lifestyle Choice card without looking.
1
1
123
10 copies of Lifestyle Choice Cards, cut to form individual cards, (30 total). Shuffle them and place them in a bag or other container.
Leader ActionLine your participants up standing in a single row, shoulder to 1. shoulder, and facing the same direction.
Mark off two spots so that the line of participants are roughly 2. divided into thirds.
Explain that the participants now represent a continuum 3. ranging from those at the left who are genetically most at risk for developing heart disease, and those at the right who are least at risk. The “thirds” represent the broader categories of high, medium and low risk groups.
Explain that each risk group correlates with a certain 4. probability of developing heart disease based on family history. Lifestyle choices involving diet, exercise and smoking can influence this risk.
QuantitiesPer Group of 30
Risk Continuum
2
3
4
9
678
5
1 space2 spaces
2Participant Action (cont.)Adjust the continuum to reflect lifestyle 2. choices:
A. Complete the following calculation:
Total # of participants = # of spaces to move
6
B. Ask the first participant to read his or her Lifestyle Choice card and move the designated number of spaces (calculated above) in the following manner:
Healthy = move the # spaces to the right
Neutral = remain where you are
Negative = move the # spaces to the left
Have each participant repeat the above 3. process until all persons are arranged into the newly formed continuum.
Have the participants reform into the divisions 4. outlined in leader action steps 1-3 and note how their risk has changed after factoring in lifestyle choices.
Within each of the thirds, the participants will 5. count off 1 to 4.
In the “high-risk” group on the left, those who 6. counted a 1 will be asked to sit down.
In the “medium-risk” group, those who counted 7. a 1 or 2 will be asked to sit down.
In the “low-risk” group on the right, those who 8. counted a 1, 2, or 3 will be asked to sit down.
Those standing represent the people that 9. developed heart disease.
Risk Continuum
Discussion PointsPeople in all risk groups develop heart disease• with the largest percentage being from the “high” risk group.
Not all people in the high risk group develop heart disease.•
Making positive or neutral lifestyle choices can influence your risk enough to prevent developing heart disease. •
(Ask participants for which this was true to raise their hands).
Sometimes, people who make positive or neutral lifestyle choices still develop heart disease (Ask participants for •
which this was true to raise their hands).
Some people who make negative lifestyle choices do not develop heart disease, even though their risk is •
increased.
3
Lifestyle Choice Cards
1
Traits and Traditions: A Make-a-Match GameTraits can be inherited from a parent, or traits can be learned. Family and cultural traditions often influence learned traits.
Can you think of a trait you have inherited? How about a trait that you have acquired by learning or tradition? Play this game to discover some common traits and traditions!
Cut out the game cards. You may want to glue or tape the pages to heavy paper first. •
Use your memory to find the cards with matching pictures. The person to collect the most matches wins!•
1. Place the game cards face down and spread them out. Decide which player will go first.
2. The first player turns over two cards, looking for a match. All players should have a chance to see the pictures on the two cards.
3. Read each card. Decide whether it describes an inherited trait (something you are born with) or a tradition (something you learn). Record your answer by checking the box next to “trait” or “tradition”.
4. If the pictures on the cards MATCH, the player keeps the cards and takes another turn. If the pictures on the cards DO NOT MATCH, the player does not keep the cards. The cards are again turned face down.
5. The next player turns over two more cards, looking for a match. Continue to label each card as either a trait or a tradition.
6. Play until all the matches have been found. The person to collect the most matches wins!
This project is supported by grant U33MC00157 from the Health Resources and Services Administration, Maternal and Child Health Bureau, Genetic Services Branch and the March of Dimes.To learn about our permissions policy, visit http://learn.genetics.utah.edu/permissions/
Did You Know?Inherited traits are physical characteristics that can be passed down from parent to child.
Preparation
Object of the game
Instructions
HintCards with matching pictures have different phrases. One card in the pair describes a trait, and the other card in the pair describes a tradition.
2
I have attached earlobesTrait □ Tradition □
I have pierced ears
Trait □ Tradition □
I can roll my tongue
Trait □ Tradition □ Trait □ Tradition □
Trait □ Tradition □ Trait □ Tradition □
Trait □ Tradition □ Trait □ Tradition □
I like to eat spicy foods
I have dimples
I greet others with a smile
My natural hair color is brown
I use dye to change my hair color
3
I am left-handed
Trait □ Tradition □
I use my hand to catch a ballTrait □ Tradition □
I am color-blind
Trait □ Tradition □ Trait □ Tradition □
Trait □ Tradition □ Trait □ Tradition □
Trait □ Tradition □ Trait □ Tradition □
I like to create art
I have allergies
I care for a pet
I have freckles
I lay in the sun to get a tan
Traits TriviaEvery person is unique, yet we all have traits we share in common with others. Families share many traits in common because they are related. But unrelated individuals will also have traits in common.
Traits Trivia includes two activities that can be done with any family or group of individuals. Using the Traits Trivia game cards, you’ll identify traits you have inherited and traits you share in common with others. Then, try to be the last one standing as you discover a combination of traits that is unique to you!
Cut out the game cards. You may wish to glue or tape them on heavy paper first. •
Invite your group to sit in a circle. Hold up one game card at a time to show a picture of an inherited trait. •
All who have this trait should stand or raise their hand. Continue with each game card to find similarities and differences among individuals in your group.
Did you share a trait with another group member? An unrelated individual? »
Did you find a trait that was unique to you? »
Did each person in your group have a different combination of the traits described? »
Once the group is familiar with all of the inherited traits described, try this second activity!
Shuffle the game cards, then draw a card from the top of the deck. Invite your group to stand up and form a •
circle. Show everyone the picture of the trait.
Everyone who has this trait should stay standing. Those who do not have the trait should sit down. Once a •
person sits down, they should not get up again. Continue with each game card until only one person is left standing.
How many cards did it take to find one person with a unique combination of traits? »
Shuffle the cards and play again as many times as you would like. •
Preparation
Instructions
Did You Know?Inherited traits are physical characteristics that can be passed down from parent to child. Learned traits are acquired through interactions with the environment.
Attached earlobes Can roll tongue Dimples Right-handed
Freckles Naturally curly hair Cleft chin Allergies
Cross left thumb over right
Can see red & green
What’s Your Family Health Story?How to Gather Family Health Information
Getting StartedExplain to your relatives that you are interested in the family’s health story. Collect some basic health information about your family members using the Health Family Tree Information Boxes. Let them know that any information they provide will help you and your entire family improve their health.
The next time you’re at a family gathering, make sharing your family health stories a tradition. It may save your life and the lives of those you love!
Common Health Problems that Run in Families
Heart disease•
Cancer•
Stroke•
Diabetes•
Asthma•
Osteoporosis•
High blood pressure•
High cholesterol•
Depression•
“The knowledge a person has of their family’s health history could be life saving, if that person chooses to heed the possibilities” - Judy
“ The only thing you have control over in your family health history is to empower yourself enough to be aware of what you’re potentially at risk of so you can recognize the symptoms or prevent the disease from occuring.” - Arianna
Corin Royal Drumm
ond
Recording family health information and sharing it with your doctor is an important first step to improving your health, regardless of your family structure.
Tracking diseases that run in your family will help your doctor better predict what you need to do to stay healthy.
How to Interview Your FamilyThe health stories of your siblings, parents and grandparents will be the most useful to your doctor. You may also want to gather information about your aunts and uncles, half-brothers or half-sisters (if any) and cousins.
Follow-up QuestionsIf a relative has experienced a health problem, ask follow-up questions that will help you learn more. Find out how old they were when the health problem started, and ask about any lifestyle factors that may have contributed to the problem (diet, exercise, overweight, smoking, etc.).
Living relatives can also provide important health information about family members who are deceased. Find out how old a family member was when they died and ask about the cause of death.
Remember to be respectful of others’ wishes. Some family members may be reluctant to share their health information with you. Just ask them to share what they can.
Additional ResourcesVisit the following websites to obtain more information about family health history, including additional tools your family can use!
Learn.Genetics (http://learn.genetics.utah.edu) Using Family History to Improve Your Health contains information about common diseases that run in families, and what it means to be “at risk”.
The Utah Department of Health (http://health.utah.gov/genomics/familyhistory/toolkit.html) Family Health History Toolkit contains materials for your family, plus links to more information about the importance of knowing your family’s health history.
“I was surprised to learn what I did about my health family history. It wasn’t until I put it into a pedigree, or family tree, that I began to see the pattern of depression that ran from generation to generation.”- Jenny
“I try to be a good example and share what I know about our family health history so future generations won’t have to worry about repeating the same fate.” - Marian
Important to Find Out
A description of any health problems •
The age at diagnosis (when the condition started)•
Allergies to foods or medications•
Lifestyle and health habits •
If deceased, the age and cause of death•
Who Do I Need to Interview in my Family?
Also Important
Aunts and Uncles•
Half-Brothers and Half-Sisters•
Cousins•
Most Important
Parents•
Brothers and Sisters•
Grandparents•
Maya Jones
Health Family Tree Information Boxes
Does this family member smoke? ❑ Yes ❑ NoIf yes, Cigarettes smoked per day:Number of years smoking:
Is this family member deceased?❑ Yes ❑ NoIf yes, Age at death:Cause of death:
Health-related lifestyle or environmental factors for this family member:
❑ Heart Disease
❑ Cancer
❑ Stroke ❑ Diabetes
❑ Asthma
❑ Osteoporosis
❑ High Blood Pressure
❑ High Cholesterol
❑ Depression/Mental Health
❑ Other ____________
Family member first name:Relationship:Date of birth:Health problems (check all that apply):
Age of onset:
__________________________________________________________________________________________
Does this family member smoke? ❑ Yes ❑ NoIf yes, Cigarettes smoked per day:Number of years smoking:
Is this family member deceased?❑ Yes ❑ NoIf yes, Age at death:Cause of death:
Health-related lifestyle or environmental factors for this family member:
❑ Heart Disease
❑ Cancer
❑ Stroke ❑ Diabetes
❑ Asthma
❑ Osteoporosis
❑ High Blood Pressure
❑ High Cholesterol
❑ Depression/Mental Health
❑ Other ____________
Family member first name:Relationship:Date of birth:Health problems (check all that apply):
Age of onset:
__________________________________________________________________________________________
Does this family member smoke? ❑ Yes ❑ NoIf yes, Cigarettes smoked per day:Number of years smoking:
Is this family member deceased?❑ Yes ❑ NoIf yes, Age at death:Cause of death:
Health-related lifestyle or environmental factors for this family member:
❑ Heart Disease
❑ Cancer
❑ Stroke ❑ Diabetes
❑ Asthma
❑ Osteoporosis
❑ High Blood Pressure
❑ High Cholesterol
❑ Depression/Mental Health
❑ Other ____________
Family member first name:Relationship:Date of birth:Health problems (check all that apply):
Age of onset:
__________________________________________________________________________________________
Does this family member smoke? ❑ Yes ❑ NoIf yes, Cigarettes smoked per day:Number of years smoking:
Is this family member deceased?❑ Yes ❑ NoIf yes, Age at death:Cause of death:
Health-related lifestyle or environmental factors for this family member:
❑ Heart Disease
❑ Cancer
❑ Stroke ❑ Diabetes
❑ Asthma
❑ Osteoporosis
❑ High Blood Pressure
❑ High Cholesterol
❑ Depression/Mental Health
❑ Other ____________
Family member first name:Relationship:Date of birth:Health problems (check all that apply):
Age of onset:
__________________________________________________________________________________________
Adap
ted
with
per
mis
sion
Creating Your Health Family Tree
After having conversations with each family member organize your family health history into a pedigree chart.
Here’s How:
Cut out each family member’s Health Family Tree Information Box checklist
Arrange the checklists on a poster or large piece of paper in the following manner. Do not tape or glue the checklists until the last step!
Starting with the oldest generation, place parents together. This is Generation I.
Place the children of each set of parents below each couple in birth order. This is Generation II.
Place the children of the members of Generation II below their parents in birth order. This is Generation III.
Continue adding generations in this manner until you have correctly arranged all of your family members.
Tape or glue the arranged checklists to your poster or paper. Draw lines between the checklists to indicate their relationships.
1
2
3
4
5
1
2
3
4
5
Name
Date
Family Traits and Traditions: A Make-a-Match Game
Traits can be inherited from a parent, or traits can be learned. Family and cultural traditions often influence learned traits.
Can you think of a trait you have inherited? How about a trait that you have acquired by learning or tradition? Play this game with your family to discover some common traits and traditions!
Cut out the game cards. You may want to glue or tape the pages to •
heavy paper first.
Use your memory to find the cards with matching pictures. The person •
to collect the most matches wins!
1. Place the game cards face down and spread them out. Decide which member of your family will go first.
2. The first player turns over two cards, looking for a match. All players should have a chance to see the pictures on the two cards.
3. Read each card. Decide whether it describes an inherited trait (something you are born with) or a tradition (something you learn from others). Record your answer by checking the box next to “trait” or “tradition” .
4. If the pictures on the cards MATCH, the player keeps the cards. They then take another turn. If the pictures on the cards DO NOT MATCH, the player does not keep the cards and turns them face down.
5. The next player turns over two cards, looking for a match. Continue to label each card as either a trait or a tradition.
6. Play until all the matches have been found. The person to collect the most matches wins!
Preparation
Object of the game
Instructions
Note to FamiliesWe have been learning about “traits” at school. Inherited traits are physical characteristics that can be passed down from parent to child. This family activity can help your child learn to identify inherited and learned traits.
HintCards with matching pictures have different phrases. One card in the pair describes a trait, and the other card in the pair describes a tradition.
Name
Date
I have attached earlobesTrait □ Tradition □
I have pierced ears
Trait □ Tradition □
I can roll my tongue
Trait □ Tradition □ Trait □ Tradition □
Trait □ Tradition □ Trait □ Tradition □
Trait □ Tradition □ Trait □ Tradition □
I like to eat spicy foods
I have dimples
I greet others with a smile
My natural hair color is brown
I use dye to change my hair color
Name
Date
I am left-handed
Trait □ Tradition □
I use my hand to catch a ballTrait □ Tradition □
I am color-blind
Trait □ Tradition □ Trait □ Tradition □
Trait □ Tradition □ Trait □ Tradition □
I like to create art
I have allergies
I care for a pet
I have freckles
I lay in the sun to get a tan
Name
Date
Family Traits TriviaWe all have inherited traits that we share in common with others. Families share many traits in common because parents pass down inherited traits to their children. Yet, every person has a combination of traits that is unique to them.
What traits do you share in common with others in your family? What traits are unique to you? Do this activity with your family to find out!
** Individuals in your family do not need to be related to participate in this activity.
Cut out the game cards. You may wish to glue or tape them on heavy paper first. •
Invite your family to sit in a circle. Hold up one game card at a time to show the picture of a trait. All family •
members that have this trait should stand or raise their hand. Continue with each game card to find similarities and differences among family members.
Did you have a trait in common with a parent? »
Did you have a trait that a parent does not have? »
Did each person in your family have a different combination of the traits described? »
Once the group is familiar with all of the inherited traits described in this activity, try this second activity!
Shuffle the game cards and place the deck face down. Invite your family to stand up and form a circle. Draw a •
card and hold it up to display the picture of the trait.
All family members who have this trait should stay standing. Those who do not have the trait should sit down. •
Once a person sits down, they should not get up again. Continue with each game card until only one person is left standing.
How many cards did it take to find one person with a unique combination of traits? »
Shuffle the cards and play again as many times as you would like. •
Try this activity at a larger gathering of extended family or friends. Do you think more or less cards will be •
needed before only one person is left standing?
Preparation
Instructions
Note to FamiliesWe have been learning about inherited “traits” at school. These are physical characteristics that can be passed down from parent to child. This family activity can help your child learn to identify inherited traits.
Name
Date
Attached earlobes Can roll tongue Dimples Right-handed
Freckles Naturally curly hair Cleft chin Allergies
Cross left thumb over right
Can see red & green
Materials needed
Instructions
1 2
Handy Family Tree
Trace the right and left hand of each family member onto a piece of colored paper
One large piece of paper or poster •
board
Colored paper (one or two for each •
member of your family)
Scissors•
Pens or markers•
Tape or glue•
Cut out the handprints
Note to FamiliesWe have been learning about “traits” at school. Inherited traits are physical characteristics that can be passed down from parent to child. This family activity can help your child distinguish between inherited and learned traits.
A family tree is a picture that shows members of your family. It can include information about each person. Do this activity to create your own family tree!
Optional
Trait no one else in your family has
Trait shared with a brother or sister
Trait shared with a parent
Trait shared with a grandparent
Word describing your character
Favorite game, sport or hobby
Favorite pet
Favorite food
3
4
5
Draw a tree trunk onto a large piece of paper or poster board.
On each finger of your left handprint list a trait (physical characteristic) that you have inherited such as:
eye color•
hair color•
dimples•
freckles•
chin shape (smooth or cleft)•
ability to roll the tongue•
earlobe attachment (attached or free)•
hairline shape on the forehead (smooth or pointed)•
height•
Add a small picture of each family member to the palm of one handprint. •
Write their name, date of birth, and place of birth on the palm of the other handprint.
Include handprint shapes for family members who were not available •
to draw their hands. See how your parents’ or grandparents’ favorites compare to yours!
Glue or tape your family’s handprints above the trunk to form a tree. Place the oldest person’s pair of hands at the bottom. Work upward until you place the youngest person’s pair of hands at the top.
On each finger of your right handprint, list a trait that you have acquired or learned.
Color or mark with an “x” the squares below when instructed to do so The square marked “free” is a free space
B I N G OAunt I have
allergiesStraight hairline Freckles Mother
I cross my right thumb over my left when I clasp
my hands
Can not taste PTC Curly hair Neighbor can
not taste PTC Straight hair
Father Grandmother Free Attached earlobes Dimples
I have a different
trait than the person sitting
next to me
Cleft chin Can taste PTC Uncle Can not roll tongue
Detached earlobes
Shared trait - Left
Trait in common -
Right
I cross my left thumb over my
right when I clasp my hands
Least common trait
TRAi sT bingo
B I N G O
Name
Date
Bingo QuestionsYou may ask the questions in order, at random, or have students draw numbers.
1. Color the square marked I cross my right thumb over my left when I clasp my hands if this describes you.
2. Color the square marked Shared trait-Left if you share a trait with the person sitting to your left.
3. Color the square marked Least common trait if you have a trait that not many people in the class share.
4. Color the square marked Neighbor can not taste PTC if you sit next to someone who can not taste PTC.
5. Color the square or squares naming the relatives from whom you do not inherit traits
6. Color the square or squares naming the relatives from whom you do inherit traits
7. Color the square marked I have allergies if you have this trait.
8. Color the square marked Trait in common - Right if you and your neighbor to the right share a common trait.
9. Find the two squares for tasting, or not tasting, PTC and color the one that applies to you.
10. Find the two squares describing earlobes and color the one that applies to you.
11. Color the square marked Straight hairline if you have this trait.
12. Color the square marked Can not roll tongue if you have this trait.
13. Color the square marked I have a different trait than the person sitting next to me if this describes you.
14. Find the two squares describing hair texture and color the one that applies to you.
15. Color the square marked Freckles if you have this trait.
16. Color the square marked Dimples if you have this trait.
17. Color the square marked Cleft chin if you have this trait.
18. Color the square marked I cross my left thumb over my right when I clasp my hands if this describes you.
Traits BingoModule
The Basics and Beyond: An Introduction to Heredity
Generations of Traits - Instructions
1. With a partner, label six cups as shown:
2. Arrange the cups as shown above and place six pom-poms in the cups, following the
directions below:
Grandfather A - red Grandfather B - yellow
Grandmother A - brown Grandmother B - green
The colored pom-poms are the traits that each of the grandparents have. Color the pom-pom pictures on the Generations of Traits Worksheet to show the traits for each grandpar-ent.
3. Close your eyes and pick three traits from Grandfather A and three traits from Grandmoth-er A and place them in the cup labeled Mother. These are the traits that Mother inherited from her parents. Color the pom-pom picture on the worksheet to show the traits Mother has.
4. Close your eyes again and pick three traits from Grandfather B and three traits from Grandmother B, and place them in the cup labeled Father. These are the traits that Father inherited from his parents. Color the pom-pom picture on the worksheet to show the traits Father has.
5. Mother and Father have four children: Mary, George, Elizabeth and Carl. To determine the traits that Mary will inherit from Mother and Father, close your eyes and take three pom-poms from Mother and three pom-poms from Father. Color the diagram to show the traits that Mary inherited.
6. Next, return the traits that you took from Mother and Father. (Look at your diagram if you forget where each trait came from.) Now, close your eyes again and choose the traits that George will inherit (3 from Mother, 3 from Father). Color the diagram to show George’s traits.
7. Return the traits you took from Mother and Father and repeat the process to find the traits for Elizabeth and then Carl.
8. Answer the questions on the Generations of Traits Questions sheet.
Grandfather A Grandmother A Grandfather B Grandmother B
Mother Father
In this activity you will track different traits (represented by colored pom-poms) through three generations of “Ginger People”. You will need the Generations of Traits Worksheet to follow along.
Name
Date
Generations of Traits - Questions
1. Would Mary, George, Elizabeth and Carl look identical to (have the same traits as) their parents?
2. Did all four children inherit exactly the same traits or is there some variation?
3. How many of the four children inherited a trait from each one of the grandparents?
4. Is there a child that didn’t inherit a particular trait? If so, which trait (color) was it?
Name
Date
ModuleThe Basics and Beyond:
An Introduction to Heredity
An Inventory of My Traits
Traits are observable characteristics that are passed down from parent to child.
An individual will have many traits they share in common with others.
An individual’s overall combination of traits makes them unique.
Some traits are more common in a population than others.
Includes a fun optional activity in which students predict the number of traits it will take to distinguish a student volunteer from everyone else in the class.
Includes a math extension in which students calculate the frequency of traits in their classroom, then compare their calculations with given frequencies for the general population.
Special Features You’ll Find Inside
Class Time:30 minutes
20 minutes to review activity and make copies of student pages
Prep Time:
Logistics
Time Required
Copies of student pages
How to construct and read bar graphs
Materials
Prior Knowledge Needed
Appropriate For:
Students take an inventory of their own easily-observable genetic traits. Working in small groups, they observe how their trait inventories differ from those of others. Students record their observations in a data table and make a bar graph to show the most and least common traits in the group.
Abstract Learning Objectives
An Inventory of My TraitsModule
The Basics and Beyond: An Introduction to Heredity
Activity instructions:
Begin by demonstrating one of the traits listed in • An Inventory of My Traits: Survey (page S-1). Ask students who possess this trait to stand. Point out the relative numbers of students standing and sitting for the trait. Continue this process with 2-3 more traits.
Explain that traits are observable characteristics we inherit from •
our parents. Some traits are common in a population (our class) while others are not. And, every person has a different overall combination of traits that makes them unique.
Divide students into groups of four or more. Have each student in •
the group complete An Inventory of My Traits: Survey (page S-1) to determine their unique combination of the traits described.
After students complete the survey, have them tally their group •
information on the data table (page S-2) and draw a bar graph (page S-3).
Optional• : You may collect the traits data from the whole class by creating a large wall chart (see example on the left). Have a representative from each group fill in their data. Once all the data has been collected, have the students make a bar graph from the class data or make one large graph together.
Optional activity:
Ask students to predict how many traits they would have •
to look at on the Survey in order to identify any given classmate as unique.
Select a volunteer who would like to determine his or her •
uniqueness. Ask all students to stand.
Have the volunteer call out one of their traits at a time, •
beginning with question 1 on the Survey and continuing in sequence. For each trait, direct all students who do not share that trait to sit down; students who share the trait remain standing. Once a student sits down, they do not get up again.
Classroom Implementation
One copy of student pages S-1 to S-3
QuantitiesPer Student
Common MisconceptionsStudents may think that the more common traits are “better”, but this is not always the case. Sometimes traits simply show up more frequently in the human population.
More advanced students may think that dominant traits are more common than recessive traits. However, frequency has very little to do with whether a trait is dominant or recessive. That is, a dominant trait is not necessarily more common and a recessive trait is not necessarily rare in a population.
An Inventory of My TraitsModule
The Basics and Beyond: An Introduction to Heredity
Continue in this way until the volunteer is the only one standing. Count the number of traits it took to •
distinguish the volunteer from everyone else in the class. Compare this number with the students’ predictions.
Repeat with several additional volunteers.•
Math extension:
Have students practice converting fractions to decimals, then decimals into percentages by calculatig the •
frequency of the following traits in your classroom: tongue rolling, handedness and hand clasping.
∙ Students can then compare their calculated frequencies with those for the general population (provided in the table below).
Example: # of students with the trait/# of students in the class x 100 = ________% 15 tongue rollers / 21 students in the class x 100 = 71%
Trait Frequency in General Population*
Tongue rolling Can roll tongue – 70%Cannot roll tongue – 30%
Handedness Right handed – 93%Left handed – 7%
Hand clasping Left thumb on top – 55%Right thumb on top – 44%No preference – 1%
instructions from one generation to another.
The characteristics of an organism can be described in terms of a combination of traits. •
Standards
*Frequencies for traits are from Online Mendelian Inheritance In Man (see http://www.ncbi.nlm.nih.gov/omim/).
NCERT/CBSE
Grades 8-9: Content Standard C: Life Science - Reproduction and Heredity• Every organism requires a set of instructions for specifying its traits. Heredity is the passage of these
An Inventory of My TraitsModule
The Basics and Beyond: An Introduction to Heredity
Additional ResourcesVisit the Teach.Genetics website to get more great resources like these!
An Inventory of My Traits - SurveyWhat combination of these traits do you have? Complete the survey to find out.
1. I have detached earlobes Yes No
2. I can roll my tongue Yes No
3. I have dimples Yes No
4. I am right-handed Yes No
5. I have freckles Yes No
6. I have naturally curly hair Yes No
7. I have a cleft chin Yes No
8. I have allergies Yes No
9. I cross my left thumb over my Yes No right when I clasp my hands together
10. I can see the colors red and green Yes No ( I am not color blind)
11. The hairline on my forehead is Yes No straight.
12. I am a: Male Female
Name
Date
An Inventory of My Traits - Data TableHow many people in your group have each trait?
Fill in the data table below by counting the number of people who marked “yes” and the number of people who marked “no” for each trait.
TRAIT YES NO
Detached earlobes
Tongue rolling
Dimples
Right-handed
Freckles
Naturally curly hair
Cleft chin
Allergies
Cross left thumb over right
See the colors red and green
Have a straight hairline
Name
Date
Nam
e
Date
An Inventory of My Traits - Graph
Make a bar graph show
ing how m
any people in your group answered “yes” for each trait.
Be sure to label each trait under the bar you draw
for it.
# of students
543210
Traits
yes no
yes no
attached unattached
earlobes:
PTC tasting:
tongue rolling:
yes no
yes no
attached unattached
earlobes:
PTC tasting:
tongue rolling:
yes no
yes no
attached unattached
earlobes:
PTC tasting:
tongue rolling:
yes no
yes no
attached unattached
earlobes:
PTC tasting:
tongue rolling:
yes no
yes no
attached unattached
earlobes:
PTC tasting:
tongue rolling:
yes no
yes no
attached unattached
earlobes:
PTC tasting:
tongue rolling:
yes no
yes no
attached unattached
earlobes:
PTC tasting:
tongue rolling:
yes no
yes no
attached unattached
earlobes:
PTC tasting:
tongue rolling:
Follow the directions below to create a DNA recipe for a dog. Using the Dog Traits Key, read your DNA recipe and make a drawing of your dog showing all of its traits.
Directions:1. Make sure you have an envelope containing “Dog DNA”.2. Determine the first trait of your dog (body shape) by randomly picking a
piece of dog DNA out of the envelope.3. Look at the symbols on the DNA strip you have chosen. Match the pattern to
one you see on the Dog Traits Key for body shape. 4. Circle the picture for body shape that matches the DNA piece that you
picked. 5. Set the piece of DNA aside and repeat steps 1-4 for the next trait on the key.6. After circling the matching picture, tape the second piece of DNA to the first
to make one long strand. This will become the DNA recipe for your entire dog.
7. Repeat these steps for each of the traits listed on the Dog Traits Key. 8. When you have finished, draw your dog with all of its traits (the traits you
have circled on the Dog Traits Key) on a separate piece of paper. 9. As instructed by your teacher, hang up the picture of your dog along with its
DNA recipe (the DNA pieces you chose attached in a long strand).
Is your dog different from or the same as others in the class?
A Recipe for TraitsA set of instructions called DNA makes a “recipe” for traits in all organisms. Information in a DNA strand is grouped into small segments. Each segment is made of even smaller units (like recipes are made of words, and words are made of letters). Differences in the DNA “alphabet” are what make differences in traits (just like a different sequence of letters makes different words, and a different recipe).
Name
Date
Body Shape
Head Shape
Ears
Legs
Do
g T
rait
s K
ey
Small, Thin, Long, Straight
Large, Thin, Long, Tapered
Medium, Very Muscular, Short
Large Semi-Muscular, Straight
Long, Thin Flat Short Droopy
Small, Pointy Big Droopy Medium Square Medium Droopy
Long, Thin Short, Stubby Medium Stocky, Muscular
Name
Date
Eyes
Tail
Coat Color
Hair
Dark Brown Light Brown Blue Green
Short Nub Long with Short Hair
Pompon Tipped Long and Bushy
Brown Black Red-Brown Yellow
Curly, Short Straight, Short Straight, Long Wavy, Long
Do
g T
rait
s K
eyName
Date
DN
A S
trip
s A
A Recipe for TraitsModule
The Basics and Beyond: An Introduction to Heredity
DN
A S
trip
s B
A Recipe for TraitsModule
The Basics and Beyond: An Introduction to Heredity
DN
A S
trip
s C
A Recipe for TraitsModule
The Basics and Beyond: An Introduction to Heredity
DN
A S
trip
s D
A Recipe for TraitsModule
The Basics and Beyond: An Introduction to Heredity
