You are a rabbit breeder, and you decide that you want rabbits with long fur. The phenotypic variance of fur length is 4 cm2. The covariance of fur length between between full sibs is 1 cm2. The mean fur length in the initial population is 3 cm. You choose to breed the top 1/3 of the population with the longest fur, and their mean fur length is 5 cm. Assume that the covariance between sibs is due to only additive genetic variance. a) What is the narrow sense heritability (h^2 ) of fur length? b) What do you expect the mean fur length to be in the progeny of rabbits you breed? c) How many generations of this selection regime will it take for the mean fur length of the population to be 10 cm? (Assume heritability and additive genetic variance remain unchanged throughout this process.)
Genetic Variation
Genetic variation refers to the variation in the genome sequences between individual organisms of a species. Individual differences or population differences can both be referred to as genetic variations. It is primarily caused by mutation, but other factors such as genetic drift and sexual reproduction also play a major role.
Quantitative Genetics
Quantitative genetics is the part of genetics that deals with the continuous trait, where the expression of various genes influences the phenotypes. Thus genes are expressed together to produce a trait with continuous variability. This is unlike the classical traits or qualitative traits, where each trait is controlled by the expression of a single or very few genes to produce a discontinuous variation.
You are a rabbit breeder, and you decide that you want rabbits with long fur. The
phenotypic variance of fur length is 4 cm2. The covariance of fur length between between
full sibs is 1 cm2. The mean fur length in the initial population is 3 cm. You choose to breed
the top 1/3 of the population with the longest fur, and their mean fur length is 5 cm. Assume
that the covariance between sibs is due to only additive genetic variance.
a) What is the narrow sense heritability (h^2 ) of fur length?
b) What do you expect the mean fur length to be in the progeny of rabbits you breed?
c) How many generations of this selection regime will it take for the mean fur length of the
population to be 10 cm? (Assume heritability and additive genetic variance remain
unchanged throughout this process.)
Phenotypic variations refer to changes that occur in traits or characteristics that can be observed. These traits can be physical, behavioral, or any other observable feature. Phenotypic variations arise from a combination of both genetic and environmental factors. It is an important concept to understand how traits are inherited and vary within a population.
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