1. In a population of Lesser Snozzlewhompins, horn length is controlled by a sin

Question

1. In a population of Lesser Snozzlewhompins, horn length is controlled by a single locus H, with the genotypes HH, Hh and hh representing long, medium and short horn length, respectively. Given the following changes in genotype numbers between generations, calculate the absolute fitness (), relative fitness (W), and selection coefficient (s) for each genotype.

a) Which genotype shows the highest fitness? Which genotype is being selected against the most strongly?

b) How have the allele frequencies changed between generations N0 and N1?

c) Assuming the selection and fitness values remain the same, estimate the genotype frequencies for gen. N2.

d) Over numerous generations, what do you predict will happen to the frequencies of alleles H and h? Be sure to explain your answer

Explanation / Answer

Here showing from a population of Lesser Snozzlewhompins, whose horn length is controlled by a single locus H, with the genotypes are represented in the tabulated form is explained as the N0 or the initial population and N1 being the population after one generation.

Now calculating the values: 1. absolute fitness (): This is defined as the total number of surviving offspring that an individual produces during its lifetime.

For the genotypes HH the absolute fitness is, Individuals from a specific genotype/ number of individuals from the parental genotype = 135 + 138/ 123 = 273/123 = 2.21,

For Hh is , 135 +138 +70 / 104 =343/104= 3.3,

For hh is, 138 +70/ 87 = 208/87 = 2.4.

Relative Fitness (W): The ratio of surviving offspring of one genotype to other, the comparison among them. The calculation is = Absolute fitness of genotype (X) / Absolute fitness of most successful genotype.

For HH allele, 2.21 / 3.3 = 0.67,

For Hh allele, 3.3/3.3 = 1,

For hh allele, 2.4/3.3 = 0.73.

Selection coefficient (s): Here at population genetics study this is a measure of the relative fitness of a phenotype. Here the proportional amount is considered, comparing the fitness of a phenotype to another favored phenotype.

s = 1 - (WHH / WHh) / (WHh / WHh) / (Whh / WHh)

So for HH genotype

s = 1 - (WHh / WHh) = 1 - (1/ 1) = 1. 100 % survival fitness,

in case of HH individuals s = 1 - (WHH / WHh), = 1- (0.67 / 1) = 0.33, so the survival rate is 33 %,

While the hh alleles have, s = 1 - (Whh / WHh) = 1 - ( 0.73 / 1) = 0.27, 27 % is the survival fitness.

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.