Question

a) What are the meanings of V_P, V_G, V_E?

b) How genetic and environmental variance affect the distribution of phenotypes in a population.?

c) What is the meaning of heritability and how does it respond to selection?

d) How can the resemblance between relatives be used to determine if the heritability of a trait is greater than zero for a trait in a population?

Answer 1

Ans a) All of these terms have got to do with the genetic heritability and helps in better understanding of variance at genetic level. VP mean total phenotypic variance which is contributed to a particular organism through total difference in the genetic level as well as the environmental variance meaning the climate they grew up in. VG mean genetic variance which means different in the gene sequence between individuals. The VE is environmental variance is appearance or the phenotypic characteristics that is contributed due to the difference in the environment of two individual or organism in a particular population.

Ans b) The genetic and environmental variation contributes to the phenotypic difference between individuals. The genetic variation is basically variation or different in gene sequence or the allele present and hence is one of the driving force for the process of evolution. It enables natural selection and hence enable the survival of certain alleles over other. The genetic variation is caused by many factors like mutation, random mating, recombination etc. and hence it shapes the phenotypic characteristics. The environmental factors also contribute to the phenotypic characteristic as the organism or individual develop and evolve based on their environment and hence some phenotypic characteristics become more prominent than the others.

Ans c) Heritability is basically a measure of a statistic which helps in measuring or identifying the degree of variation in terms of phenotypic characteristics present in an organism due to the genetic variation the exist between individual within that population. When there is more phenotypic difference due to genetic variation, the heritability value is higher and when there is less phenotypic variation, heritability value is lower.

Ans d) The resemblance between relative helps in determining that heritability of trait is greater than zero for the trait because the phenotypic differences comes from difference in the genetic level and does not come from the environment. there will be genetic differences between the close relative and this will contribute to the phenotypic difference and hence place the value of heritability close to one.