introduction to genetics. it all started here the beginnings of genetics genetics - is the study of...
TRANSCRIPT
Introduction to Genetics
It all started here
The Beginnings of genetics
Genetics - is the study of heredity
or the study of passing of traits from parent to offspring
* The father was Gregor Mendel
Questions:
Who is the father of genetics?
What is genetics?
HE.912.C.1.4 Analyze how heredity and family history impact health
What was known? Chromosomes determine
everything about living things Come in pairs During meiosis they segregate to
make a gamete (egg or sperm) Fertilization - pairs the
chromosomes again The 2 types are autosomes and
sex chromosomes
Questions:Explain the types of
chromosomes and their importance.
What is the importance of meiosis?
Why is fertilization important?
SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.SC.912.L.16.17 Compare mitosis and meiosis and relate to the process of sexual and asexual reproduction and their consequences for genetic variations.HE.912.C.1.4 Analyze how heredity and family history impact health
When fertilization occurs … Each parent gives one of each pair of chromosomes
Importance of segregation
Without segregation an offspring will not get the correct number of chromosomes – resulting in mutations or deathToo many is called polyploidy
Example: Down syndrome - extra 21st chromosome
Questions:
What is segregation and why is it so important?
SC.912.L.16.1 Use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritanceSC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.HE.912.C.1.4 Analyze how heredity and family history impact health
Extra 21
Extra 13
Mendel’s Discoveries On chromosome are genes
They determine a specific trait
Gene have different forms called alleles Dominant alleles - strong
(shown with a capital letter) Recessive alleles - weaker
(shown with a lower case letter)
Questions:
What is the difference between a gene and allele?
What 2 forms can alleles take?
SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.HE.912.C.1.4 Analyze how heredity and family history impact health
Importance of alleles Typically there are 2 alleles
that represent each traitThis two letter combination
is called the genotype TT or Tt or tt
We use the genotype to determine what it looks like – called the phenotype
Questions:
What is the difference between the genotype and phenotype?
SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.
Determining what the trait looks like
Dominant traits - are always seen RR and Rr both will show the
dominant trait
Recessive traits – only seen if there are no dominants present rr will show the recessive trait
Questions:
What is the difference between a dominant and recessive trait?
SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.HE.912.C.1.4 Analyze how heredity and family history impact health
Determining what the trait looks like
Codominance - both traits are seen Example:
multicolored shells or cats
SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.
Incomplete dominance – none are dominant so they mixExample: red flower plus
white flower = pink flower
Questions:
What is the difference between codominance and incomplete dominance?
Determining what the trait looks like
SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.
Multiple alleles – when there are more than 2 alleles that control the trait But still only 2 letters in the
genotype Blood type has A B and O
A blood type: XAXA or XAXO
B blood type: XBXB or XBXO
AB blood type: XAXB
O blood type: XOXO
Questions:
Explain what multiple alleles means and explain an example.
Determining what the trait looks like
SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.HE.912.C.1.4 Analyze how heredity and family history impact health
Polygenic traits – have more than 2 genes for a trait that all effect the outcome The genotype has more
than 2 letters (AAbbCc)Example - skin color, hair
color, height
Questions:
What is a polygenic trait and why does it allow for so much diversity?
Determining what the trait looks like
SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.
Determining the possibilities Probability – is the likelihood
an event will occur In genetics the Punnett
square is diagram used to determine the genetic probability of an offspring
It tells you what the parents have, what the children could have, but it never tells you the actual outcome
Questions:
What is probability and how is it used in determining the possible genetic outcomes?
SC.912.L.15.15 Describe how mutations and genetic recombination increase genetic variation.
Using the Punnett Square First - determine the
genotypes both parentsHomozygous dominant -
both letters are capitalHomozygous recessive -
both letters are lower caseHeterozygous - one letter
is capital and the other is lower case
Questions:What is the
difference between homozygous and heterozygous?
Why do you need to know the parent genotypes first?
SC.912.L.16.1 Use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance.
Step 2: Fill in the square
If B=brown eyes and b=blue eyesCross a homozygous dominant and a homozygous recessive individual
B B
b
b
Bb Bb
Bb Bb
SC.912.L.16.1 Use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance.
Interpreting the Punnett Square
RatiosGo from most dominant to
most recessive Include genotypic ratios Include phenotypic ratios
Questions:
How do you find ratios and percentages for the Punnett square?
SC.912.L.16.1 Use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance.
What if we look at more than one trait?
Follow the Principle of independent assortment – says that genes for different traits segregate independently In other words – each parent will
give one of each letter to the offspring
Example: RrYy Possibilities alleles passed are
RY Ry rY ry
Questions:
What does the principle of independent assortment state?
Why is this idea important?
SC.912.L.16.1 Use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance.SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.
Genetic disorders Dominant disorders – on
the dominant genes All it takes is one bad gene
and you have itExample: Achondroplasion -
dwarfism
Questions:
What is a dominant disorder and why is it so dangerous?
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.HE.912.C.1.4 Analyze how heredity and family history impact health
Dwarfism
Primordial Dwarfism
Genetic disorders Recessive disorders – are
on the recessive alleles If you have 2 recessive you
have it If you have 1 you are a
carrierExample:
Cystic Fibrosis – mucus in lungs
Albinism – no melanin
Questions:
What are recessive disorders?
Why is being a carrier still dangerous?
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.HE.912.C.1.4 Analyze how heredity and family history impact health
Albinism
Genetic disorders Sex linked disorders – on the
X and Y chromosomes If it is on the X
Females – both parent must give it Males – only mom gives it
If it is on the y Females – don’t get because no y Males – if dad has it all sons have it
Examples on X: Baldness – loosing hair Hemophilia – blood can’t clot properly
Questions:
Why is it more dangerous for boys than girls when it comes to sex linked disorders?
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.HE.912.C.1.4 Analyze how heredity and family history impact health
Baldness
Color Blindness
http://www.kcl.ac.uk/teares/gktvc/vc/lt/colourblindness/cblind.htm
http://webexhibits.org/causesofcolor/2.html#vissamp
Genes affected by the environment
Characteristics can be affected by the environmentExamples:
Nutrition affects height Scholastic verses non-
scholastic home affect intelligence
Questions:
How can environmental factors affect characteristics?
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.
Why organisms naturally different
Crossing over Independendant
assortment Mutations
Questions:
Explain organisms naturally differ?
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.HE.912.C.1.4 Analyze how heredity and family history impact health
How humans cause variations? Mutations – environmental or
chemical Hybridization – crossing 2 dissimilar
organisms Selective breeding – crossing 2 of
same species Inbreeding – crossing organisms in
the same family tree Genetic engineering - the process of
man reading, editing, and reinserting pieces of DNA
Questions:
Explain how man has caused genetic difference in organisms.
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.SC.912.L.16.10 Evaluate the impact of biotechnology on the individual, society, and the environment, including medical and ethical issues.
1. Extract DNA2. Read the Sequence3. Cutting the DNA4. Separating DNA – using electrophoresis 5. Pasting – using enzymes6. Making Copies
Cell Transformation in Bacteria Cell transformation - process of
taking DNA from one cell into another cell
They use bacteria Foreign DNA is joined to a
circular DNA called a plasmid Plasmid is mixed with bacteria Treated with anti-bacteria to
kill all cell except those with the new gene
Questions:
Explain how man has caused genetic difference in organisms.
SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.SC.912.L.16.10 Evaluate the impact of biotechnology on the individual, society, and the environment, including medical and ethical issues.
Using Bacteria For Genetic Engineering