Question

A population of crickets lives on a barrier island in the Gulf of Mexico. Some are brought into the lab for a breeding experiment. From the experiment it is determined that the phenotypic variance for wing length is 108.2 mm2 and the additive genetic variance for wing length is 33.7 mm2. A study is carried out on the wild population. The mean wing length of the crickets is 8.2 mm. The island is hit by a hurricane. The surviving crickets have a wing length of 6.9 mm. Given the information provided, what is the predicted wing length in the next generation? What assumption do you have to make in order to make your calculation? Why might this assumption not be correct?

Answer 1

According to breeder's equation,

R is the change in mean over one complete generation

h² is the heritability

S is the selection differential.

The heritability h² is calculated using the formula

vg is the variance in genotype and vp is the phenotypic variance.

According to question given above, vg = 33.7 mm²and

vp = 108.2 mm²

then,

The selection differential S is the difference between population average and the average of the parental population

Then,

Therefore,

The wing length of the next generation

The negative value of selection differential will favor lower trait value.

The variation between the individuals is the sum of genetic and environmental factors. These factors may affect the result.