Question

a reessive allele on the x chromosome is responsible for red-green color blindness in humans. a woman with normal vision whose father is color-blind marries a color-blind male. what is the probability that a son of this couple will be color-blind?Please draw the punnet square.

Answer 1

50%

Step-by-step explanation:

Let the allele for red-green color blindness be represented by c.

Normal vision woman whose father is color-blind will be
`X^CX^c`

Color-blind male will be
`X^cY`

`X^CX^c` x
`X^cY`

Progeny:
`X^CX^c, X^CY, X^cX^c, X^cY` (See the attached image)

Out of the 2 male progeny, 1 is affected for color-blindness while the other is not affected. This gives a 50% probability that a son of the couple will be color-blind.