# Genetics

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Hi, I really need help in how to approach this question:

A species of tiny antelope, known as the zephyr, has an XY system of sex determination, similar to mammals. Zephyr males have small antlers and females do not. The antlers can be two pronged (2-pr) or three pronged (3-pr) and this is determined by a single gene which is found on the X chromosome (there is no allele for 2-3 pronged on the Y chromosome). In a large population, 74% of the adult males have two-pronged antlers and the rest of the adult males have three pronged antlers.

a) What is the frequency of the three pronged allele in the adult male population?

Is it 0.26??

b) Assuming that the allele frequency is the same in the females, what are the expected genotypic frequencies in the females.

Any help would be very much appreciated. Thanks.

• Genetics - ,

I think a) is 0.26.
b) if you take the 2-pr allele to be 'p' and the 3-pr allele to be 'q' then genotypic frequencies are p^2 for Xp2Xp2, 3^2 for Xp3Xp3 and 2(p)(q) for Xp2Xp3.
so Xp2Xp2 = 0.55
Xp3Xp3 = 0.07
Xp2Xp3 = 0.19