Question

You discovery a pre-maturely bald male mouse in your colony. Interested in the possible commercial funding opportunities in male-pattern baldness research. You first task is to understand how this mutation is related to gender. What would you do to distinguish between a gene influenced by gender and one determined by a sex chromosome?

Answer 1

Answer: To determine whether a trait is autosomal or sex-linked you must look at the males from the F₁ and the reciprocal F₁ crosses. If the trait is X-linked then the males from the F1 will always have the trait of their homozygous mother. If its Y-linked then all the males would have it and the females wont. Consequently, the results of the reciprocal F₁ crosses will be different. Males may or may not resemble their sisters depending on dominance. If the males from the reciprocal F₁ crosses look the same and they look like their sisters, then the trait is autosomal.