“Polygenics Penny Lab”
Experimental Questions: Why do some traits appear in nearly endless varieties?
Introduction: Polygenic traits are traits that are controlled by more than one gene, i.e. height, weight, hair color,
skin color. If these traits were controlled by Mendelian Inheritance humans would only show two heights, a tall
height or a short height. Polygenic inheritance allows a wide range or spectrum of traits.
Polygenic Gamete (Sex Cell) Formation: A man is 5 feet 7 inches tall, has 3 heads (tall genes) and 3 tails (short
genes). He will give 3 genes to his child. These 3 genes can be given randomly. He can give 3 tall genes and no
short genes, 2 tall genes and 1 short, 1 tall gene and 2 short, 0 tall genes and 3 short. These are all the possible
combinations that he can give his child. The height of the mother will dictate the genes that she will give to the
child. The combination of the mother's genes and the father's genes will decide the height of the child.
Pre Lab Questions:
1) What fraction of their genetic material does each parent give to their child? Explain why.
2) If a male is 5 feet 9 inches tall, it means that he has 4 tall genes and 2 short. He will only give 3 genes to his
child. What are the possible combinations of genes that he can give?
He can give _____ tall and ______ short
He can give _____ tall and ______ short
He can give _____ tall and ______ short
3) The male is 5 feet 7 inches and the female is 5 feet 5 inches. Is it possible for them to give their child the
necessary genes so the child can be 5 feet 11 inches tall? Explain your answer.
Procedure:
1. Assuming both parents carry three tall genes and three short genes, you will model the inheritance of height
for ten different offspring. Flip a coin six times to determine how many tall and short genes the child
inherits. Heads represents a tall gene and tails represents a short gene.
2. Record all of your data along with the class data in the tables below
Data:
Table 1: Group results
Flip (Your Group)
Number of tails
Number of heads
1
2
3
4
5
Table 1: continued
Flip (Your Group)
6
7
8
9
10
Number of tails
Number of heads
Table 2: Group and class results
Flip
Situation
0T6H 1T 5H
2T 4H
3T 3H
4T 2H
5T 1H
6T 0H
Your Group
Total
Class Total
Construct a Bar Graph for both your results and the class results.
Conclusion: Use the following Height Table to answer the questions.
Penny Situation
Height
O Tails and 6 Heads
6 feet 1 inch
1 Tail and 5 Heads
5 feet 11 inches
2 Tails and 4 Heads
5 feet 9 inches
3 Tails and 3 Heads
5 feet 7 inches
4 Tails and 2 Heads
5 feet 5 inches
5 Tails and 1 Head
5 feet 3 inches
6 Tails and 0 Heads
5 feet 1 inch
Remember: Heads are tall genes. Tails are short genes.
Conclusions:
1) If the male is 5 feet 5 inches tall and the female is 5 feet 3 inches tall, what is the tallest height that their child
could attain? Explain.
2) If the male is 5 feet 7 inches tall and the mother is 5 feet 3 inches tall, what is the shortest height their child could
attain? Explain.
3) List 3 other polygenic traits.
4) How are polygenic traits different from traits that only require 2 genes?
5) Why do you think that some children are taller than their parents?
6) Analyze the class data and propose an explanation for an apparent trends in height.
Answer Key!
1) Do parents give (All or Half) of their genetic material to their children? Half
2) If a male is 5 feet 9 inches tall, it means that he has 4 tall genes and 2 short. He will only give 3 genes to his
child. What are the possible combinations of genes that he can give?
He can give ___3__ tall and __0____ short
He can give ___2__ tall and __1____ short
He can give ___1__ tall and __2____ short
3) The male is 5 feet 7 inches and the female is 5 feet 5 inches. Is it possible for them to give their child the
necessary genes so the child can be 5 feet 11 inches tall? Explain your answer. Diagrams are often useful. The
father can give 3 talls and 0 shorts and the mother can give 2 talls and 1 short. The child will be 5 feet 11 inches
tall.
4) If 2 parents are 5 feet 7 inches, is it possible to have a child that is 6 feet tall? Explain how this is possible. Yes.
Both parents can give 3 talls and 0 shorts. This will give the child 6 talls and 0 shorts. This means the child will be
6 feet 1 inch tall.
5) If the male is 5 feet 5 inches tall and the female is 5 feet 3 inches tall, what is the tallest height that their child
could attain? Explain. The male can give 2 talls and 1 short and the female can give 1 tall and 2 shorts. The child
could have 3 tall and 3 short, making the child 5 feet 7 inches tall.
6) If the male is 5 feet 7 inches tall and the mother is 5 feet 3 inches tall, what is the shortest height their child could
attain? Explain. The male and female can give 3 short and 0 talls. The child could have 6 shorts. This will make
the child 5 feet one inch tall.
7) List 3 other polygenic traits. Hair color, skin color, eye color, body shape—anything that deals with size, shape,
color or number (like fingerprints—the total ridge count).
8) How are polygenic traits different from traits that only require 2 genes? The polygenic traits have a wide
variation in each trait.
9) Why do you think that some children are taller than their parents? The children can have more tall genes than
either parent. The environment also plays a role in the expression of traits. Remember Genotype + Environment =
Phenotype.