Genetics 1)Roan is a coat color pattern common in horses, in which the animal ha
ID: 256333 • Letter: G
Question
Genetics
1)Roan is a coat color pattern common in horses, in which the animal has intermingled colored and white hairs in at least part of its body. After visiting a ranch, you observe solid red horses, solid white horses, and several roan individuals. The rancher has conducted breeding experiments and shares the following observations:
Red mare (?) x red stallion (?) = 100% red offspring
White mare x white stallion = 100% white offspring
Red mare x white stallion = 100% roan offspring
White mare x red stallion = 100% roan offspring
Roan mare x roan stallion = 25% red : 25% white : 50% roan offspring
a)Propose a mode of inheritance for this trait. Include the number of genes, the alleles, and the relationships among the genes/alleles. (3 points)
b)You collect data from a wild population of horses on the island of Assateague in coastal Virginia. You observed 473 red horses, 29 white horses, and 81 roan horses. Is this population in Hardy-Weinberg equilibrium at this locus? Show your calculations. (5 points)
c)Propose an evolutionary force that may be responsible for your observations in (b). Explain clearly a hypothetical scenario that would lead to this force having the effect, and briefly explain why it would create the effect that you have observed. (4 points)
Explanation / Answer
Answer:
Answer:
a).
It is incomplete dominance type of inheritance. One gene with two alleles are involved.
Red = RR; White = rr ; Rr= Roan
b)
Frequency of red = p^2 = 473/ total progeny = 0.81
Frequency of roan = 2pq= 81/583 = 0.14
Frequency of white= q^2 = 29/583 = 0.05
Hardy-Weinberg equilibrium = p^2 + 2pq + q^2 = 1
0.81 + 0.14+0.05 =1
So the population is in equilibrium
c). The population is in equilibrium because of random mating. It may be the responsible for observations mentioned in the question.