1.1. A locus has two alleles: A (dominant) and a (recessive). The genotype frequ

Question

1.1. A locus has two alleles: A (dominant) and a (recessive). The genotype frequency of homozygous recessive individuals is 0.30. Assuming the population is in Hardy-Weinberg equilibrium, calculate: A) The frequencies of both alleles (A and a). A: p= 0.45 a: q= 0.55 Aa: 2pq= 0.50 p+q=1 p +0.55=1 p=0.45 B) The genotype frequencies of homozygous dominant and heterozygous individuals. AA: p2=0.203 aa: q2= 0.3 Aa: 2pq= 0.50 p+q=1 p +0.55=1 p=0.45 C) If the population has 500 individuals, how many are heterozygous for this locus? 0.45 of the population would be heterozygous, so 225 individuals would be heterozygous 1.2. Now, assume this locus is under selection and is linked to variable fitness among different genotypes. The relative fitness of individuals with the dominant phenotype is 0.9. Calculate: A) The average fitness of the population, w, where w = p2 x w11 + 2pq x w12 + q2 x w22 W11=0.4 W12=0.9 W22= 1.0 B) If aA1 = -0.03, will the frequency of A increase or decrease in the next generation? C) What is the frequency of A in the next generation (At+1)? Hint: p = p x (aA1/w) I am having trouble with 1.2, I attached 1.1 to use as a reference. Thanks!

Explanation / Answer

Solution ----

Please Note: The notations used are extremely confusing. Please take due care of superscript and subscript next time.

A)

The average fitness of the population, w, where w = (p2 x w11) + (2pq x w12) + (q2 x w22)

Given data: w11 = 0.4; w12 = 0.9; w22 = 1.0

Average fitness = (0.203 * 0.4) + (0.50 * 0.9) + (0.3*1) = (0.0812 + 0.45 + 0.3) = 0.8312

B)

There seems to be a misprint here. What does ‘a’ in aA1 signify? A1 gene has not been mentioned. Please post this again.

C)

Frequency of ‘A’ allele in the next generation = genotype frequency of p2) + ½ (genotype frequency of 2pq) = (0.0812) + (½ * 0.45) = 0.3062

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