2. Selection for sternopleural bristle number was performed on the D. melanogast

ID: 174643 • Letter: 2

Question

2. Selection for sternopleural bristle number was performed on the D. melanogaster.. Each generation, 10/100 flies of each sex were selected as the highest (H line). Data were collected as follows over four generations (G) in males (females were similar): G YP Ys 0 9.05 11.20 1 10.71 13.60 2 11.60 14.10 3 12.03 - (a) Determine the selection differential (SD ) and the response (YR) for each generation in each selected line. (b) What is the estimate of realized heritability in each generation and the average estimate over generations

Explanation / Answer

Selection differential (SD ) and the response (YR)

The table is

Generations

0 9.05

11.20

10.71

13.60

11.60

14.10

12.03

For 1st generation:

Selection differential (SD ) = Ys- Yp where Yp is parental population and Ys is selected parents

S0 = 11.20-09.05 =2.15

Response (YR) = h2S where h is heritability which is counted by High line given in the question =10/100 = 0.1

So the Response (YR0) = h2S = (0.1)2 x 2.15= 0.0215

For 2nd generation:

S1 = Ys- Yp= 13.60-10.71=2.89

YR1 = h2S = 2.89 x 0.01 = 0.0289

For 3rd generation:

S2 = Ys- Yp= 14.10-11.60=2.5

YR2 = h2S = 2.5 x 0.01 = 0.025

For 4th generation:

S3 and YR3 cannot countable as the data is not available.