All answers must start with the equation that was used to answer the question, a

Question

All answers must start with the equation that was used to answer the question, and all work must be shown.

4. In a population of diploids, 1 individual out of 100 exhibits the homozygous recessive phenotype. What is the expected frequency of heterozygous genotypes.         

4b. In the above population, 25 heterozygous individuals are observed. Is the population in HWE?

5. If a genome is 4.2 Mb in length, with an average mutation rate of 1.8 x 108 mutations/site/generation, how many mutations should occur in the average gamete in a single generation?

6. In a diploid population where the homozygous recessive phenotype occurs at a frequency of 0.04 and has a relative fitness 90% that of the dominant phenotype, what is the mean fitness?

6b. How does the frequency of the recessive allele change as a function of purifying selection?          

Explanation / Answer

4. Predicting genotypic frequency is done using Hardy-Weinberg Equilibrium

The equation is p2 + 2pq + q2 = 1. Where p2 - Frequency of homozygous dominant; 2pq - frequency of heterozygous individuals and q2 - frequency of homozygous recessive individuals.

In the given question 1 is homozygous recessive out of 100 populaiton; 1/100 = 0.01

Therefore q2 - 0.01, square root of this will give us q = 0.316

Since p+q = 1 ; We can solve for p

p = 1- q = 1- 0.316 = 0.684.

since 2pq is frequency for heterozygous by substituting for p and q we get

2x 0.316 x 0.684 = 0.432.

4b. If the population have 25 heterozygoes it does not exist in HWE since, by substituting for 2pq we dont get the sum of 1.

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