MBG 2040 Chapter Notes - Chapter 4: Epistasis, Inbreeding Depression, Pleiotropy

• School: University of Guelph
• Department: Molecular Biology and Genetics
• Course: MBG 2040
• Professor: Schisler/ Mosser

Document Summary

A heterozygote with a phenotype different that that associated with either homozygous form. A heterozygote shows characteristics found in each of the associated homozygotes. A classic example of a gene with multiple alleles is the one that controls coat colour in rabbits. The colour determining gene, denoted by c , has four alleles: c (albino), ch (himalayan), cch (chinchilla) and c+ (wild type) Because most rabbits are homologous for the c+ allele, this is designated as the wild type. The other alleles of the c gene are mutants- altered forms of the wild type that have arisen during evolution. Polymorphic (greek origin; having many forms) when all alleles of a gene are found at appreciable frequencies in the population. The functional relationships among the members of a series of multiple alleles can be studied by making heterozygous combinations through crosses between homozygotes. The wild type allele is completely dominant over the other alleles in the series.