Environment and Gene interaction, Basis of Genetic environment interaction

• The phenotypic value is determined partly by the genotype and partly by the environment experienced by individual during the development and expression of phenotypic value.
• There are two component parts of the phenotypic value attributed to genotype and environmental effects.
• The interaction of genes with external environment viz, climatic, nutritional, managemental factors, etc., is called genotype-environment interaction.
• The genes and environment may interact in number of ways:

a. The environment may effect genetic composition of a population by pressure of selection and this leads to evolutionary changes.

b. The environment may distort the segregation and recombination expected on genetic library.

c. It may change the genetic material as mutagenic effects of radiation and various chemical substances and also as conditioning effects and paramutation.

d. The environment may interact with genotypes to produce differences in phenotypic values of the individuals of a population.

• The differential response of different genotypes in different environment is called GEI by a biologist.
• When a genotype fails to give the same response in different environment, it is taken as GEI.
• The interplay of genetic and environmental factors in effects on the phenotypic expression of a trait is GEI.