Question

Sexual selection on traits involved in mate choice can lead to complex patterns of genetic variation in populations. The African Great Lakes contain a stunning diversity of cichlid fish species, which have recently evolved due to a combination of ecological adaption and sexual selection. In one recently evolved species, we observe the following pattern: An autosomal (not sex linked) locus “X” involved in pigmentation has different effects in male fish than female fish. There are two alleles in this system. In males, “x” acts recessively to produce bright red gill markings, while in females, the same allele acts dominantly to produce a dull striped pattern. A survey of male fish reveal that 56.25% have bright red gill markings.

A.)If we assume the population is in H-W equilibrium, what percentage of the female fish do we expect to have the dull striped pattern?

B.) In the scenario above, the phenotypic effect of alleles at locus X is dependent on the allelic state of the sex determining locus in these fish. What is the term for this kind of genetic interaction?

Answer 1

1A.

frequency of 2pq + frequency of q² = 0.375 + 0.5625 = 0.9375 will have dull stripes pattern. Hence 93.75 % females will have dull striped pattern.

1B Sexual antagonism, as variation in sex is having opposite effect on dominance of same allele