IMED2004 Study Guide - Final Guide: Genetic Disorder, Zygosity, Mendelian Inheritance
Document Summary
An organism"s genetic makeup, or allele combinations. An organism"s physical appearance, or visible traits. The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment. Other factors affecting gene expression may interfere. In 1902 cuenot published his work on coat colour in mice, believing it fit. Cuenot was the first to suggest more than 2 alleles can exist at a single locus. That cancer was inherited & that genes encoded enzymes. The lethal yellow gene means the mice did not show the ratios predicted by. Thus, mendel"s principles alone are not adequate to explain inheritance of all characteristics. Additional factors act at various loci & can alter the phenotypic ratios. The maternal copy is randomly chosen for inactivation in some somatic cells and the paternal copy is randomly chosen for inactivation in other somatic cells. Pertaining to both alleles of a gene (in a heterozygote).
