Question

1. The MN blood group is examined in a population, and the following numbers of genotypes are observed:
5 MM
25 MN
20 NN
Assuming Hardy-Weinberg conditions, what is the expected frequency of MM individuals in the next generation?

2. The mean number of offspring produced by each of three genotypes is shown below. What is the fitness (W) for the genotype MM?

10 MM
30 MN
50 NN

3.The mean number of offspring produced by each of three genotypes is shown below.

10 MM
30 MN
50 NN
What is the selection coefficient for the genotype NN?

This is all the information given. The answer for 1 is 0.123 the answer for 2 is .2 and the answer for 3 is 0, but I have no idea how to do these problems, can someone please explain how to solve these questions

Answer 1

1) Given, total population = 5+25+20 = 50

So, total number of alleles = 2 x total population = 2 x 50 = 100

Now, total number of M alleles = (2 x Numbers of MM genotype) + Numbers of MN genotype = 2 x 5 + 25 = 35

So, frequency of M alleles = Total number of M alleles / Total number of alleles = 35/100 = 0.35

Now, expected frequency of MM genotype = (frequency of M alleles)2 = (0.35)2 = 0.123 (Up to 3 decimals)

2) Relative fitness of MM = Reproductive rate of MM / Highest reproductive rate = 10/50 = 0.2

3) Relative fitness of NN = Reproductive rate of NN / Highest reproductive rate = 50/50 = 1

Now, selection co-efficient = 1 - relative fitness

So, selection co-efficient for NN = 1 - Relative fitness of NN = 1 - 1 = 0