ZOOLOGIC

Polygenic inheritance: When a trait is controlled by more than one pair of contrasting gene ( generally a pair of allele) and follows non Mendelian inheritance pattern it is called polygenic trait and the pattern of Inheritance called Polygenic Inheritance. It refers to Inheritance of quantitative traits which are influenced by multiple genes to different loci and environment may also be involved. A quantitative trait is a measurable phenotype that depends on the cumulative actions of many genes and the environment. These traits can vary among individuals, over a range, to produce a continuous distribution of phenotypes. Examples include height, weight and blood pressure.   It is charact erized by Ø   Involvement of several loci in the expression of the trait. Ø   There is no dominant and recessive relationship at each of the loci. Ø   The loci at in an addition fashion, in adding and detracting a small amount from the phenotype. Ø   The environment interacts with the genot