Name______

Heredity Lab: Making Ugly Babies from a Shallow Gene Pool

Background Information

As you look around the room, you can see that no one else is exactly like you. One of the reasons for the success of sexually reproducing species is the abundance of variations that appear within each generation of offspring. Because genes are randomly inherited from each parent, each individually created offspring will be absolutely unique.

In this laboratory, you will be performing “coin tosses” to simulate the passing of alleles from parents to offspring for a variety of traits. Heredity is, of course, much more complicated than tossing coins but this simulation provides a simplified model of how genes are passed on from one generation to the next, and how those genes are related to the traits seen in the offspring. We have taken some liberties in simplifying some of these traits – please note that many of these traits are controlled by multiple genes and exhibit much more elaborate modes of inheritance than what is shown here.

Materials: Coins (2 per team) and Colored pencils

Procedure

1. Determine the sex of your “baby”. Working with a partner, shake both coins in hand, and release coins onto the table top.

·  If both coins come up heads or both come up tails, your baby is a GIRL.

·  If one coin comes up heads and the other comes up tails, your baby is a BOY.

2. Determine the traits of your “baby”. For each trait in the charts found on the next two pages, you will perform one coin toss.

·  If both coins come up HEADS, the baby will show the DOMINANT trait.

·  If both coins come up TAILS, the baby will show the RECESSIVE trait.

·  If one coin comes up heads, and the other comes up tails, the baby will show the HYBRID trait. Sometimes the hybrid trait is the same as the dominant trait, and other times it is a blend between the dominant and recessive traits.

3. As you complete each coin toss, be sure to complete the Data Table on the next page, indicating your baby’s inherited GENOTYPE and PHENOTYPE for each trait. Use the Characteristics Chart as your guide to the genotypes and phenotypes.

4. Once you have collected all the traits of your baby, draw a picture of your baby on the last page.

5. Answer the analysis questions.

DATA TABLE:

TRAIT / GENOTYPE / PHENOTYPE
Sex
Length of eyelashes
Shape of eyebrows
Size of nose
Shape of lips
Size of ears
Size of mouth
Freckles
Dimples
Color of hair
Ability to roll tongue
Shape of face
Cleft in chin
Hair Texture
Widow’s peak
Shape of eyes
Position of eyes
Size of eyes
Spacing of eyes
Size of feet
Color of eyes

Characteristics Chart

Trait / Dominant
(both heads) / Hybrid
(one head, one tail) / Recessive
(both tails)
Shape of Face /
Round (RR) /
Round (Rr) /
Square (rr)
Cleft in Chin / No cleft (CC) /
No cleft (Cc) /
Cleft in Chin(cc)
Hair texture /
Curly (HH) /
Wavy (Hh) /
Straight (hh)
Widow’s peak /
Widow’s Peak (WW) /
Widow’s Peak (Ww) /
No Widow’s Peak (ww)
Shape of eyes / Almond (AA) /
Almond (Aa) /
Round (aa)
Position of eyes /
Straight (SS) /
Straight (Ss) /
Slant upwards (ss)
Size of eyes / Large (LL) / Medium (Ll) / Small (ll)
Spacing of eyes / Close together (EE) / Average Distance (Ee) / Far apart (ee)
Size of feet / Large (FF) / Medium (Ff) / Small (ff)
Color of eyes / Brown (BB) / Green (Bb) / Blue (bb)
Length of Eyelashes / Long (LL) / Long (Ll) / Short (ll)
Shape of eyebrows / Bushy (HH) / Bushy (Hh) / Fine (hh)
Size of nose / Large (LL) / Large (Ll) / Small (ll)
Shape of lips / Thick (KK) / Thick (Kk) / Thin (kk)
Size of ears / Large (EE) / Large (EE) / Small (ee)
Size of mouth / Large (MM) / Large (Mm) / Small (mm)
Freckles / Freckled (FF) / Freckled (Ff) / Not freckled (ff)
Dimples / Dimpled (DD) / Dimpled (Dd) / Not dimpled (dd)
Color of hair / Brown (WW) / Brown (Ww) / Blond (ww)
Ability to roll tongue / Can roll tongue (RR) / Can roll tongue (Rr) / Can’t roll tongue (rr)

Analysis Questions

1.  What do the coins represent in this laboratory? (1pts)

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2.  What does the flipping of each coin represent in this laboratory? (1pts)

______

3.  The parents in this laboratory have the same type of genotype for each trait. Are the parents heterozygous or homozygous for each trait? How do you know? (2pts)

______

4.  Why do you only use one coin for each parent? (2pts)

______

5.  What biological process does bringing the results of each coin flip together represent? Explain. (3pts)

______

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6.  What is the probability that an offspring from these parents will have a baby with freckles? Show the cross (Punnett Square) to prove it. (2pts)

Probability:______

7.  Explain why finding the traits of an offspring produced asexually does not require a Punnett Square. (3pts)

______

Picture of Baby

Grading

Data Table – 21pts

Picture of Baby – 5pts

Analysis Questions – 14pts

Total Points – 40pts