Human Inheritance & Celebrity Genetics LabInstructions

CLASS COPY – PLEASE RETURN THIS PACKET.

Introduction: With an understanding of heredity and probability, biologists have learned about the genetics of many human traits. For many of these traits, several pairs of genes are involved and the pattern of inheritance is complex. For this activity we will assume that most of the traits we are studying are regulated by the alleles of only one gene pair, with one allele from the father and one from the mother.

Why do people, even closely related people, look slightly different from each other? The reason for these differences in phenotypes is the different combination of genes possessed by each individual.

To illustrate the tremendous variations in human inheritance, you will imagine that you have the opportunity to marry and start a family with your favorite celebrity. Your baby will receive a random combination of genes that each of you, as genetic parents, will contribute. Each normal human being has 46 chromosomes (23 pairs- diploid) in each body cell. In forming the gametes (egg or sperm), one chromosome of each chromosome pair will be given, so these cells have only 23 single chromosomes (haploid). In this way, you contribute half of the genotype for the child and your celebrity spouse will contribute the other half. In doing this lab, you must assume that your dream celebrity has not had any plastic surgery, and he or she was born with the traits that you’ve grown to love.

You’ll firsts look at your phenotypes for several facial features to narrow down your genotypes. Then you’ll do the same for your celebrity partner. You will then use this information to create your child.

Objectives: In this activity you will:

1. Determine your phenotype for several traits.

2. Determine (as far as possible) your genotype for the same traits.

3. Determine the frequency of dominant & recessive traits in the class.

4. Determine the phenotypes & genotypes of your dream celebrity.

5. Determine the phenotypes & genotypes of the child you would have with your dream celebrity.

6. Track the inheritance of genetic disorders in a pedigree.

7. Use a pedigree to predict family members’ genotype.

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Procedures:Part I:Phenotypes and genotypes of common traits

You will determine your phenotype and try to determine your genotype for the traits listed in the Part I Data Table.

Remember, if you show a dominant trait, you may be homozygous or heterozygous for that trait. Suppose, however, that one of your parents shows the recessive trait. In that case, the parent would have passed on a gene for the recessive trait and you would be heterozygous for that trait. If neither of your parents shows the recessive trait, you may not know whether you are heterozygous or homozygous for that trait. In this case, put a blank (_) for the unknown allele.

Since your parents are not here, only record your genotype as heterozygous if you display the dominant trait and you know for sure one of them displays the recessive trait. If you show the recessive trait, record it as the phenotype as well as the genotype, with two recessive alleles.

1.) Face Shape:

Round (AA, Aa) Square (aa)

2.) Chin Size:

Prominent (BB, Bb) Less Prominent (bb)

3.) Chin Shape: Only record this trait if chin size is prominent. The genotype bb prevents the expression of this trait. If the chin is less prominent, put a dash (-----) through genotype and phenotype on the data table.

Round (CC, Cc) Square (cc)

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4.) Cleft Chin: Only flip coins for this trait if the chin size is prominent. The genotype bb prevents the expression of this trait.

Present (DD, Dd) Absent (dd)

5.) Skin Color (polygenic inheritance): To determine the color of skin or any other trait controlled by more than 1 gene, you will need to flip the coin for each gene pair. Dominant alleles represent color; recessive alleles represent little or no color. For example, if there are 3 gene pairs…

6 dominant alleles (EEFFGG) = very dark brown5 dominant alleles (EeFFGG) = medium - dark brown4 dominant alleles (EeFfGG or eeFFGG) = light - medium brown3 dominant alleles (EeFfGg or eeFfGG) = dark tan /light brown 2 dominant alleles (eeFfGg or eeffGG) = tan1 dominant alleles (eeffGg) = light 0 dominant alleles (eeffgg) = very fair

6.) Hair Color: Determined by 4 gene pairs. (H, I, J, K)

8 dominant (HHIIJJKK) – black 3 dominant (hhIiJjKk) -brown mixed w/ blond 7 dominant (HhIIJJKK) – very dark brown 2 dominant(hhiiJjKk) - blond 6 dominant (HhIiJJKK) – dark brown 1 dominant (hhiijjKk) - very light blond 5 dominant (HhIiJjKK) – brown 0 dominant (hhiijjkk) - silvery white 4 dominant (HhIiJjKk) – light brown

7.) Red Color Tint in Hair: This trait is only visible if the hair color is light brown or lighter. Epistasis results when the expression of the “red tint” gene is masked by darker hair color.

For Part I, if your hair is light brown or lighter, you can determine your genotype for this trait, if it is darker, put a dash (------) through this section.

Dark red tint (L1L1) Light red tint (L1L2) No red tint (L2L2)

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8.) Hair Texture:

Curly (M1M1) Wavy (M1M2) Straight (M2M2)

9.) Widow’s Peak:

Present (NN,Nn) Absent (nn)

10.) Eye Color:Pigmented irises: If you have any color of eyes other than blue, you have pigment in the front layer of the iris. This is dominant. If there is no pigment, your eyes will appear blue which is recessive. Different color eyes result in different type and amount of pigment which relies on another gene.

OOPP – Black/Brown Oopp – Green OOPp – Dark Brown ooPP - Gray BlueoOPP – Brown with green flecks ooPp – Dark BlueOoPp – Brown oopp – Light BlueOOpp – Hazel

11.) Eye Distance:

Close (P1P1) Average (P1P2) Far Apart (P2P2)

12.) Eye Size:

Large (R1R1) Medium (R1R2) Small (R2R2)

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13.) Eye Shape:

Almond (SS, Ss) Round (ss)

14.) Eye Slantedness:

Horizontal (TT,Tt) Upward Slant (tt)

15.) Eye Lashes:

Long (UU,Uu) Short (uu)

16.) Eyebrow Color:

Darker than hair color (V1V1)Same as hair color (V1V2)Lighter than hair color (V2V2)

17.) Eyebrow Thickness:This describes thickness of eyebrows before plucking!

Thick (WW,Ww) Fine (ww)

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18.) Eyebrow Length:

Not connected (XX,Xx) Connected (xx)

19.) Mouth Size:

Long (Y1Y1) Medium (Y1Y2) Short (Y2Y2)

20.) Lip Thickness:

Thick (ZZ,Zz) Thin (zz)

21.) Dimples:

Present (AA,Aa) Absent (aa)

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22.) Nose Size:

Large (B1B1) Medium (B1B2) Small (B2B2)

23.) Nose Shape:

Rounded (CC,Cc) Pointed (cc)

24.) Nostril Shape:

Rounded (DD,Dd) Pointed (dd)

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25.) Earlobe Attachment:

Free (EE,Ee) Attached (ee)

26.) Freckles on Cheeks:

Present (FF,Ff) Absent (ff)

27.) Freckles on Forehead:

Present (GG,Gg) Absent (gg)

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*** FOR PART I & II ONLY***28.) Tongue Rolling:

A dominant allele, H, gives some people the ability to roll their tongues into a U shape when it is extended. People with the recessive alleles, hh, cannot roll their tongues. Check to see if you can roll your tongue.

29.) PTC Tasting:Individuals who can taste bitter chemical phenylthiocarbamide, PTC, have at least one dominant allele, I. Those with the recessive genotype, ii, cannot taste it. Take a piece of PTC paper from the supply station. Place the untouched end to your tongue to find out if it tastes bitter to you. Put the paper in the trash, and record your phenotype and genotype in Table 1.

30.) Bent Pinky:A dominant allele, J, results in the end joint of the little finger of each hand bending inward. Straight little fingers are a result of the recessive genotype jj. Place your hands on a flat surface, palms down, and relax. Check to see if the first joints of your little fingers are bent in or straight. If you still have trouble, hold your hands together as if you are covering your face. If the tips of the pinkies point away from one another, the pinkies are bent. Record your phenotype and genotype in Table 1.

31.) Hairy fingers:Individuals who have hair on the middle joints of their fingers (mid-digit hair) have at least one dominant allele, K. Those with two recessive alleles, kk, do not have hair on that joint. Check to see if you have hair on the middle joints of your fingers. Look for hair only on the finger shown by the white arrow below. Record your phenotype and genotype in Table 1.

32.) Hitchhiker’s thumb:A dominant allele, L, results in the ability to bend one's thumb tip backwards more than 30 degrees (hitchhiker's thumb). Stick your thumb up to see if it bends back or if it is straight. Record your phenotype and genotype in Table 1.

33.) Long palmer muscle:Make a fist and look at the inside of your write while moving your fist back & forth. If you see only two tendons, you have the dominant trait, M_. If you see three, you are recessive, mm.

34.) Color visionColor blindness is a sex-linked recessive trait, so when writing your genotype, you must include your sex chromosomes. (ex. XNY, XNXn, etc.) Are you red green colorblind or do you have normal color vision? If you are female and your dad is colorblind, then you are heterozygous.

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Part III: Determine your favorite celebrity’s phenotypes and genotypes for traits 1-27, and record them in

Table 3.

Part IV: Determine the phenotypes & genotypes of the child you would have with your dream celebrity.

Record your results in Table 4. Draw a picture of your baby when you finish. First, determine your baby’s gender. Remember, this is determined entirely by the father. The

mother always contributes an X chromosome to the child.Heads = X chromosome, so the child is a GIRLTails = Y chromosome, so the child is a BOY

Name the child (first and middle name; last name can be father’s last name, mother’s last name or hyphenated last name).

Record your genotype & your dream celebrity’s genotype for face shape (from Tables 1 & 3) in the spot for the parental cross above Punnett square 1 on p. 15. If the genotype is unknown, assume it is heterozygous.

Determine the child’s face shape by completing the Punnett square. Each square of the Punnett square is assigned a number. Roll a die to see which genotype your child will have. If you roll a 5 or a 6, then reroll.

Circle the genotype on the Punnett square that corresponds to the number you roll. On the Table 4, check off and record your child’s genotype and phenotype. Repeat this procedure for all 27 traits. Some traits follow special conditions, which are explained as they come up. When you have completed determining your child’s phenotype, draw a portrait of him or her.

Part V:

Read about pedigrees on pages 309 – 311 in your text and complete the genotypes and questions for the pedigrees on your answer sheet.

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Name:_______________________________________ Period: ______

Human Inheritance LabAnswer Sheet (100 points)

Part I: My Traits# Trait Phenotype Genotype

1 A Face Shape2 B Chin Size3 C Chin Shape4 D Cleft Chin5 EFG Skin Color6 HIJK Hair Color7 L Red Tints8 M Hair Type9 N Widow’s Peak10 OP Eye Color11 Q Eye Distance12 R Eye Size13 S Eye Shape14 T Eye Slantedness15 U Eyelash Length16 V Eyebrow Color17 W Eyebrow Thickness18 X Eyebrow Length19 Y Mouth Size20 Z Lip Thickness21 A Dimples22 B Nose Size23 C Nose Shape24 D Nostril Shape25 E Earlobe Attachment26 F Freckles on Cheeks27 G Freckles on Forehead28 H Tongue Rolling29 I PTC Tasting30 J Bent Pinky31 K Hairy Fingers32 L Hitchhiker’s Thumb33 M Palmer Muscle34 N Color visionIf you have the recessive phenotype, do you know your genotype?

When is the only time you determine your genotype if you are dominant for a trait? Explain.

Why can you never say for sure that you are homozygous dominant for a trait? 11

Date:

Celebrity GeneticsPart III: My Mate’s Traits – My dream celebrity is __________________________.# Trait Phenotype Genotype

1 A Face Shape

2 B Chin Size

3 C Chin Shape

4 D Cleft Chin

5 EFG Skin Color

6 HIJK Hair Color

7 L Red Tints

8 M Hair Type

9 N Widow’s Peak

10 OP Eye Color

11 Q Eye Distance

12 R Eye Size

13 S Eye Shape

14 T Eye Slantedness

15 U Eyelash Length

16 V Eyebrow Color

17 W Eyebrow Thickness

18 X Eyebrow Length

19 Y Mouth Size

20 Z Lip Thickness

21 A Dimples

22 B Nose Size

23 C Nose Shape

24 D Nostril Shape

25 E Earlobe Attachment

26 F Freckles on Cheeks

27 G Freckles on Forehead

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Part IV: Our Baby’s Traits

Parents _____________________________________ and ____________________________________

Child’s Gender____________________ Child’s Name________________________________________# Trait Genotype Phenotype

Homozygous Dominant Heterozygous Homozygous

Recessive1 A Face Shape

2 B Chin Size

3 C Chin Shape

4 D Cleft Chin

5 EFG Skin Color

6 HIJK Hair Color

7 L Red Tints

8 M Hair Type

9 N Widow’s Peak

10 OP Eye Color

11 Q Eye Distance

12 R Eye Size

13 S Eye Shape

14 T Eye Slantedness

15 U Eyelash Length

16 V Eyebrow Color

17 W Eyebrow Thickness

18 X Eyebrow Length

19 Y Mouth Size

20 Z Lip Thickness

21 A Dimples

22 B Nose Size

23 C Nose Shape

24 D Nostril Shape

25 E Earlobe Attachment

26 F Freckles on Cheeks

27 G Freckles on Forehead

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1. _________ x _________

1 2

3 4

2. _________ x _________

1 2

3 4

*3. _________ x _________

1 2

3 4

4. _________ x _________

1 2

3 4

5. ______________ x ______________ For each letter that you are heterozygous

for, flip a coin. The result will represent the allele you

give to your offspring. Heads = dominant & tails = recessive. Repeat this for your dream celebrity to

determine which alleles you’ll each give your child.

6. ______________ x ______________ For each letter that you are heterozygous

for, flip a coin. The result will represent the allele you

give to your offspring. Heads = dominant & tails = recessive. Repeat this for your dream celebrity to

determine which alleles you’ll each give your child.

*7. _________ x _________

1 2

3 4

8. _________ x _________

1 2

3 4

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9. _________ x _________

1 2

3 4

10. _____________ x _____________ Roll 3 times & add up the total of the 3 rolls.

1 2 3 4

5 6 7 8

9 10 11 12

13 14 15 16

11. _________ x _________

1 2

3 4

12. _________ x _________

1 2

3 4

13. _________ x _________

1 2

3 4

14. _________ x _________

1 2

3 4

15. _________ x _________

1 2

3 4

16. _________ x _________

1 2

15

3 4

17. _________ x _________

1 2

3 4

18. _________ x _________

1 2

3 4

19. _________ x _________

1 2

3 4

20. _________ x _________

1 2

3 4

21. _________ x _________

1 2

3 4

22. _________ x _________

1 2

3 4

23. _________ x _________

1 2

3 4

24. _________ x _________

1 2

16

3 4

25. _________ x _________ 27. _________ x _________

1 2

3 4

26. _________ x _________

1 2

3 4

Child’s Portrait

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1 2

3 4

Conclusions:1. What percentage does each parent contribute to a child’s genotype? (In each Punnett square,

what percentage of the offspring’s genotype was from the mom & what percentage was from the dad?)

2. List examples of traits (from your baby’s data) table where each of the following was shown:a. Dominant trait

b. Recessive trait

c. Incomplete dominance

d. Polygenic inheritance (HINT: Refer to instruction packet.)

e. Epistasis (HINT: Refer to instruction packet.)

Part V: Family TraitsTracing Genes in a Family

The pedigree below tracks the history of albinism in a family (as shown by shapes that have been filled in). Albinism is an autosomal recessive disorder. Use “p” to represent the allele for albinism and “P” to represent the allele for normal pigmentation. Write the genotype below each individual in the pedigree. If the complete genotype cannot be determined, record “P__.”

I.

1 2

II.

1 2 3 4 5 6 7

III. 1 2 3 4 5 6 7 8 9

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The pedigree below shows the inheritance of sickle cell anemia (ss) in a family. Fill in the genotypes of the individuals in the family in Table 2.

Generation Individual GenotypeI 1

234

II 1234

III 123456789

IV 12

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