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Genetic Science Learning Center
Deafness
Map a gene for a genetic disorder yourself!
Text Only Version
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This exercise is approximately 5 pages.

Some forms of deafness are genetically based. This means that they can be passed down (inherited) depending on the genetic circumstances.

This activity involves a pedigree or family that has genetic deafness in it. Some of the members of the family are numbered - noted in parentheses, indicating that their genetic make-up will be represented in the tables below (the number of the table corresponds with the number of the person).

The couples are represented by A, B, C... to make it easier to reference them.

PEDIGREE DESCRIPTION:
The original couple (A) are a hearing female and a deaf male (1). Couple A has two deaf children.

One deaf daughter (3) is married to a hearing male (2) - Couple B. They have one deaf son and he marries a deaf woman - Couple D.

Couple D has two children, one is a deaf daughter who lives with another woman (Couple G) and the other child is a hearing male (4) who is single.

Couple A has two children, remember. The deaf son married a hearing woman (5) - Couple C. Couple C has two deaf children. One deaf daughter (6) married a hearing male (Couple E).

Couple E has three deaf children. One daughter and two sons are born and the youngest son marries a hearing woman (7) - Couple H.

The deaf son from Couple C marries a hearing women (Couple F). Couple F has two deaf children and one hearing son. Of the two deaf children, one is a boy and one is a girl. The deaf boy is living with his deaf boyfriend and the deaf girl is single (8).

Can you find out which cell in the table is responsible for the deafness?

Below you'll find genetic "tables" for the 8 individuals from the family above. The number of the table corresponds to the number of the individual in the pedigree. Each individual's genetic makeup is represented by a table with 25 cells (5 rows by 5 columns). Each cell represents a gene. The cells are numbered and have a letter indicating the type of genetic information.

Here's the challenge! Find the piece of the genetic puzzle (the cell number) that is responsible for deafness. Exactly what are you looking for?

TABLE 1
1 - A 2 - A 3 - A 4 - A 5 - A
6 - A 7 - A 8 - A 9 - A 10 - A
11 - A 12 - A 13 - A 14 - A 15 - A
16 - A 17 - A 18 - A 19 - A 20 - A
21 - A 22 - A 23 - A 24 - A 25 - A

TABLE 2

1 - B 2 - B 3 - B 4 - B 5 - B
6 - B 7 - B 8 - B 9 - B 10 - B
11 - B 12 - B 13 - B 14 - B 15 - B
16 - B 17 - B 18 - B 19 - B 20 - B
21 - B 22 - B 23 - B 24 - B 25 - B

TABLE 3

1 - C 2 - A 3 - C 4 - A 5 - A
6 - A 7 - C 8 - A 9 - C 10 - C
11 - A 12 - C 13 - C 14 - A 15 - C
16 - C 17 - A 18 - A 19 - A 20 - A
21 - C 22 - A 23 - C 24 - C 25 - A

TABLE 4

1 - B 2 - D 3 - A 4 - D 5 - B
6 - D 7 - A 8 - D 9 - B 10 - D
11 - D 12 - C 13 - D 14 - D 15 - B
16 - C 17 - D 18 - D 19 - C 20 - A
21 - D 22 - B 23 - B 24 - D 25 - D

TABLE 5

1 - E 2 - E 3 - E 4 - E 5 - E
6 - E 7 - E 8 - E 9 - E 10 - E
11 - E 12 - E 13 - E 14 - E 15 - E
16 - E 17 - E 18 - E 19 - E 20 - E
21 - E 22 - E 23 - E 24 - E 25 - E

TABLE 6

1 - E 2 - C 3 - E 4 - E 5 - E
6 - A 7 - E 8 - E 9 - C 10 - E
11 - E 12 - C 13 - A 14 - A 15 - A
16 - C 17 - E 18 - E 19 - A 20 - E
21 - E 22 - E 23 - C 24 - E 25 - C

TABLE 7

1 - F 2 - F 3 - F 4 - F 5 - F
6 - F 7 - F 8 - F 9 - F 10 - F
11 - F 12 - F 13 - F 14 - F 15 - F
16 - F 17 - F 18 - F 19 - F 20 - F
21 - F 22 - F 23 - F 24 - F 25 - F

TABLE 8

1 - G 2 - C 3 - E 4 - G 5 - G
6 - G 7 - E 8 - G 9 - C 10 - E
11 - E 12 - G 13 - G 14 - A 15 - G
16 - G 17 - E 18 - G 19 - G 20 - E
21 - A 22 - C 23 - G 24 - E 25 - C

 

Need a hint?

How would a scientist think about this problem?

Which cell is responsible for deafness? Choose the number of the cell that you think contains the gene.

1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
16 17 18 19 20
21 22 23 24 25

How do you know your CELL is the right one?

HERE is the ANSWER!

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