In horses, the basic color of the coat is governed by the E locus. EE and Ee horses can make black pigment, while ee horses are a reddish chestnut. A different locus, the R locus, can cause roan, a scattering of white hairs throughout the basic coat color. However, the roan allele has a serious drawback: RR embryos always the during fetal development. Rr embryos survive and are roan, while rr horses survive and are not roan. The E locus and the R locus are tightly linked. Suppose that several centuries ago, a Spanish galleon with a load of conquistadors’ horses was shipwrecked by a large grassy island. Just by chance, the horses that survived the shipwreck and swam to shore were 20 chestnut roans (eeRr) and 20 nonroan homozygous blacks (EErr). On the island, they interbred with each other and established a wild population. The island environment exerts no direct selection on either locus.
a. What was D, the coefficient of linkage disequilibrium, in the initial population of 20 horses? Was the initial population in linkage equilibrium or not? If not, what chromosomal genotypes were underrepresented?
b. Do you expect the frequency of the chestnut allele, e, to increase or decrease in the first crop of foals? Would your answer be different if the founding population had been just 10 horses (5 of each color)? Explain your reasoning.
c. If you could travel to this island today, can you predict what D would be now? Do you have predictions about whether more horses will be roan versus nonroan, or chestnut versus black? If not, explain what further information you would need.
We need at least 10 more requests to produce the solution.
0 / 10 have requested this problem solution
The more requests, the faster the answer.