Question

assignment

baldness
In man, a gender-influenced character is determined by two alleles in an autosomal locus. Allel B for baldness is dominant in men, but recessive in women. The alternative allele b is recessive in men, but dominant in women.
In a large population (A) it turned out that 1% of the women were bald. Answer the following questions assuming that the population is in Hardy-Weinberg's balance with regard to the genetic system considered.
a) Calculate the expected frequency of heterozygous women among women in population A.
b) Calculate the expected frequency of bald men in population A.
c) How much of all marriages are the marriage combination (bald woman) x (non-bald man)?
d) What is the probability that the first son from a marriage between a non-bald man and a randomly-unbuttoned woman will be bald?
In another large population (B) - also in the Hardy-Weinberg equilibrium - 50% of the men were bald.
e) Calculate the expected frequency of bald women in population B.
f) How much of all marriages can be expected (bald man) x (non-bald woman) in population B?

Answer 1

a) In a large population, 1% (0.01) of the women were bald.

q^2 = 0.01

q = 0.1

So, p = 0.9 (since p + q = 1)

The frequency of heterozygous women in the population is,

= 2pq

= 2(0.9)(0.1)

= 0.18

b) The expected frequency of bald men is,

= (0.9)(0.9) + 2(0.9)(0.1)

= 0.81 + 0.18

= 0.99

c) The proportion of bald women is 0.01 and the proportion of non bald man is 0.01. So,

= (0.81)(0.01)

= 0.0081

= 0.81%

d) The probability that the first son from marriage between non bald man and non bald women is,

= (0.01)(0.81)

= 0.0081

Information about population B is required for solving questions (e) and (f).