Question

Joe is breeding cockroaches in his dorm room. He finds that the average wing length in his population of cockroaches is 4 cm. He chooses the six cockroaches that have the largest wings; the average wing length among these selected cockroaches is 10 cm. Joe interbreeds these selected cockroaches. From earlier studies, he knows that heritability h2 for wing length in his population of cockroaches is 0.6.

a. Calculate the selection differential and expected response to selection for wing length in these cockroaches.
b. What should be the average wing length of the progeny of the selected cockroaches?

Answer 1

Answer:

S =  6 cm

R = 3.6 cm

$\\A_{wing \ length } = 7.6 \ cm$

Explanation:

Using the formula:

$\\\\R = h^2 S$

where;

R = response of selection

h = heritability

S = (selection differential) i.e  mean weight after selection - mean weight before selection

S = 10 cm - 4 cm

S =  6 cm

narrow sense heritability h² = 0.6

Now; R( expected response ) =  0.6 × 6 cm

= 3.6 cm

The average wing length of the progeny of the selected cockroaches is said to be the mean wing length of the population in addition to the response to selection (R)

$\\A_{wing \ length } = (4 + 3) \ cm \\\\A_{wing \ length } = 7.6 \ cm$