Black coat color in horses is conferred by the presence of a

Black coat color in horses is conferred by the presence of a dominant B allele. Chestnut horses are genotype bb. A population of wild horses consists of 127 black horses and 30 chestnut horses. Assume that this population is at Hardy-Weinberg equilibrium for this locus.

Please round all answers correctly to 4 decimal digits.

1. What is the frequency of the B allele?

2. What is the frequency of the b allele?

3. How many horses in the population are expected to be heterozygous for this locus?

Solution

Answer:

back (BB or Bb))= dominant

chestnut (bb)= recessive

The frequency of chestnut= bb= (q2) = 30/157 = 0.19

The frequency of chestnut allele= b= (q) = Root of 0.19 = 0.44

p+q= 1

p = 1-q = 1-0.44= 0.56

The frequency of the B allele = 0.56

The frequency of the b allele = 0.44

The frequency of heterozygous = 2pq = 2 * 0.56 * 0.44 = 0.49

Heterozygous horse population = 0.49 * 157 = 77