Clouded leopards are a medium-sized, endangered species of cat, living in the very wet cloud forests of Central America. Assume that the normal spots (XN) are a dominant, sex-linked trait and that dark spots are the recessive counterpart.
Suppose, as a Conservation Biologist, you are involved in a clouded leopard breeding program. One year you cross a male with dark spots and a female with normal spots. She has four cubs and, conveniently, two are male and two female. One male and one female cub have normal spots and one each have dark spots.
What is the genotype of the mother for this sex-linked trait?
a
impossible to determine with given information
b
purebred for normal spots
c
heterozygous
d
homozygous
The mother has normal spots, which can either be the dominant XN or the recessive XD. Since the offspring include both normal-spotted and dark-spotted cubs, it is likely that the mother is heterozygous for this trait, meaning she has one copy of the dominant allele XN and one copy of the recessive allele XD.
Therefore, the correct answer is c) heterozygous.