Polygenic Traits Lab

Purpose:  This activity will demonstrate how polygenic traits work and why certain traits in a population can be graphically represented by a bell curve.

Materials:   6 pennies

Procedure:  1) Each "couple" (lab partners)  will carefully flip all six coins.
2)  Record the number of heads and tails that result from the flip in Table 1.
3) Continue to flip the coins and continue to record the number of heads and tails that result from the flip unitl the data Table 1 is completed.

Table 1.- Group Results

Flip (group) 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
#heads
#tails

4)  Complete table 2 by adding up the number of times the following situations occurred.

Table 2.- Group and class results

Flip Situation 0 Tails
6 Heads
1 Tails
5 Heads
2 Tails
4 Heads
3 Tails
3 Heads
4 Tails
2 Heads
5 Tails
1 Heads
6 Tails
0 Heads
Group total
Class total

5) Record your results from Table 2 in the computer with the class results.

6) Graph your group's results in the bar graph below:

  f      8
r      7
e     6
q     5
u     4
e     3
n     2
c    1
y     0
  0 tails
6 heads
1 tail
5 heads
2 tails
4 heads
3 tails
3 heads
4 tails
2 heads
5 tails
1 head
6 tails
0 heads

7) Record the class results in Table 2.

8)  Construct a bar graph from the class data on the graph paper included with this packet.  The number of heads and tails will go on the X axis while the number of times that the situations occurred will go on the Y axis.

___
___
  f     ___ 
r     ___ 
e    ___ 
q    ___ 
u    ___ 
e    ___ 
n    ___
c    ___ 
y         0
  0 tails
6 heads
1 tail
5 heads
2 tails
4 heads
3 tails
3 heads
4 tails
2 heads
5 tails
1 head
6 tails
0 heads

Conclusion:  Use the following height table to answer the questions on the next page

Penny Situation Height
0 Tails and 6 Heads ~ 6 feet 6 inches
1 Tails and 5 Heads ~ 6 feet 3 inches
2 Tails and 4 Heads ~ 6 feet 0 inches
3 Tails and 3 Heads ~ 5 feet 9 inches
4 Tails and 2 Heads ~ 5 feet 6 inches
5 Tails and 1 Heads ~ 5 feet 3 inches
6 Tails and 0 Heads ~ 5 feet 0 inches

Remember: Heads are dominant genes that have an effect of making one taller.  Tails are recessive and have a shortening effect.

1)  Parents give (All or Half) of their genetic material to their children.

Example for the rest of the questions:  A man is 5 feet 9 inches tall, has 3 heads (dominant genes) and 3 tails (recessive genes).  He will give 3 genes to his child.  These 3 genes will be given randomly.  The following are the possible genes for sperm:

He can give 3 dominant genes (heads) and 0 recessive genes (tails).
He can give 2 dominant genes (heads) and 1 recessive gene (tails).
He can give 1 dominant gene (heads) and 2 recessive genes (tails).
He can give 0 dominant genes (heads) and 3 recessive genes (tails).

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.

2)  If a male is 5 feet 6 inches tall, it means that he has 4 recessive genes and 2 dominant.  He will only give 3 genes to his child.  What are the possible combinations of genes that he can give?

He can give ______ dominant and _______ recessive.
He can give ______ dominant and _______ recessive.
He can give ______ dominant and _______ recessive.

3)  The male is 5 feet 9 inches and the female is 5 feet 6 inches.  Is it possible for them to give their child the necessary genes so the child can be 6 feet 6 inches tall? Explain your answer:

What is the maximum height possible for their child? _____  Minimum height?______

4)  If 2 parents are 6 feet tall, is it possible to have a child that is 6 feet 6 inches tall? Explain. 

What is the maximum height for the children?______ Minimum height?_______

5)  If the parents are both 5 feet 6 inches tall, what are the maximum and minimum heights possible for the children?

Maximum___________ Minimum___________

6) If the male is 6 feet 3 inches tall and the female is 5 feet tall, what are the maximum and minimum height possible for the children?

Maximum__________ Minimum_________

7)  List 3 other polygenic human traits:

8)  How are polygenic traits different in their expression (what you see) than traits that only require 2 genes?