Population A consists of 100 hens that are fully inbred to genetic homozygosity
ID: 261624 • Letter: P
Question
Population A consists of 100 hens that are fully inbred to genetic homozygosity and are reared in a uniform environment. The average weight of the eggs they lay is 52.0 g, and the variance is 3.5 g2 . Population B consists of 100 genetically variable hens that produce eggs with a mean weight of 52.0 g and a variance of 21.0 g 2 . Population B is raised in an environment that is equivalent to that of Population A.
a. What is the environmental variance (VE) for egg weight?
b. What is the genetic variance in Population B?
c. What is the broad-sense heritability in Population B?
Explanation / Answer
Variation in Population A is due to environmental factors as it is fully isogenic.
Therefore, environmental variance (Ve) is equal to 3.5 g2.
Population B has a total variance(Vx) of 21.0 g2 ( while being under the same environmental conditions as Population A).
We know, Vx = Ve + Vg, (Vg being genetic variance),
then Vg = Vx – Ve
or 21.0 – 3.5 = 17.5 g2 for population
Broad-sense heritability (H2) for population B is Vg/Vx or 17.5/21.0 = 0.83