Please assist with the following questions regarding evoluti

Please assist with the following questions regarding evolutionary biology. Thanks!

1) Why, in any given organism, do we expect a large fraction, if not a majority, of all possible point mutations to be neutral?

2) In the China population, blood group genotypes occur at frequencies : 0.179 for MM, 0.502 for MN, and 0.319 for NN.

a) What is the frequency of allele M? What is the frequency of allele N?

b) What are the corresponding frequencies of genotypes MM, MN, NN that we expect at Hardy-Weinberg equilibrium?

c) Do the observed genotype frequencies look close to the frequencies expected at Hardy-Weinberg equilibrium? What can you conclude?

3) In a large, closed population, most people carry allele t at a locus where the mutant allele T confers resistance to typhoid fever. A study of 1,778 individuals showed that 1,194 were tt, 526 were tT, and 58 were TT.

a) Are alleles t and T in Hardy-Weinberg equilibrium? Support your answer with appropriate calculations.

b) Did you expect this? Briefly explain why or why not.

c) Do you expect this to remain true in future generations? Briefly explain why or why not.

Solution

Answer:

2).

Genotype, MM frequency= q²= 0.179

Allele, M frequency=q= 0.42

Genotype, NN frequency= p²= 0.319

Allele, N frequency= p=0.57

MM frequency= 0.423 * 0.423 = 0.179

NN frequency = 0.57 * 0.57 = 0.319

MN frequency =2pq = 2 * 0.57 * 0.42 = 0.479

Hardy-Weinberg equilibrium= p² + 2pq + q²= 1

0.319 + 0.479 + 0.179= 0.977

Yes, observed genotype frequencies look close to the frequencies expected at Hardy-Weinberg equilibrium.

3).

Genotype, tt frequency= q²= 1194/1778 = 0.67

Allele, t frequency=q= 0.82

Genotype, TT frequency= p²= 58/1778= 0.033

Allele, T frequency= p=0.18

Genotype, Tt frequency = 2pq= 2 * 0.18 * 0.82 = 0.295

Hardy-Weinberg equilibrium= p² + 2pq + q²= 1

0.033+ 0.295+ 0.67= 0.998

Yes, the alleles t and T in Hardy-Weinberg equilibrium.