Genetics 1)Roan is a coat color pattern common in horses, in which the animal ha

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.

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