Question

Male-pattern baldness is a X-linked recessive trait, labelled X^{\text{b}}

b

start superscript, start text, b, end text, end superscript, with the dominant normal hair gene being X^{\text{B}}

B

start superscript, start text, B, end text, end superscript.

A father with the genotype X^{\text{B}}

B

start superscript, start text, B, end text, end superscriptY and a mother with the genotype X^{\text{b}}

b

start superscript, start text, b, end text, end superscriptX^{\text{b}}

b

start superscript, start text, b, end text, end superscript have a son.

What is the percent chance that the son will inherit male-pattern baldness?

Answer 1

100%

Step-by-step explanation:

Pattern baldness if X linked and recessive.

A father with
`X^BY` and a mother with
`X^bX^b` have a son.

First, let us look at the result of the cross between the two:

`X^BY` x
`X^bX^b`

male progeny:
`X^bY, X^bY`

female progeny:
`X^BX^b, X^BX^b`

The two sons resulting from the cross inherited male pattern baldness. Hence, the percentage chance that the son will inherit male pattern baldness is 100.