In: Biology
In a population of cats, the phenotypic frequency of black cats is 75 %, and the phenotypic frequency of white cats q2 is 25%. Assuming that black (B) is dominant and white (b) is recessive, calculate the appropriate frequency for BB or p2 genotype following for a population in Hardy-Weinberg equilibrium.
A |
25% |
|
B |
50% |
|
C |
75% |
|
D |
100% |
|
E |
10% |
Answer: A. 25%
Hardy Weinberg equilibrium is p2 + 2pq + q2 =1
p2 is the frequency of BB (homozygous dominant genotype)
2pq is the frequency of Bb (heterozygous genotype)
q2 is the frequency of bb (homozygous recessive genotype)
given that q2 25%
So, p2 + 2pq = 75%
According to the principle of Mendelian inheritance, offsprings of a monohybrid cross will result in a 3:1 ratio of phenotypes.
Bb X Bb BB (black)
Bb (black)
Bb (black)
bb (white)
here white bb - 25%
So, BB - 25%
Bb - 50%
So, p2 is the frequency of BB (homozygous dominant genotype) - 25%