IMED2004 Study Guide - Final Guide: Zygosity, Abo Blood Group System
Document Summary
The two copies of a gene segregate from each other during transmission from parent to offspring. The two alleles of a gene found on each of a pair of chromosomes segregate independently of one another into sex cells. Alleles segregate from one another during the formation of gametes. For a given single gene recessive disorder, expect: Homozygous or compound heterozygous mutations inherited from unaffected parents. Mutations on both copies of gene required to cause disease. Some examples differ from these standard expectations. If both alleles mutated and not identical mutation. Frequently initiated early in development, then stably maintained. Examples of this include imprinting and inactivation. When have x chr inactivation, cells derived from that cell will form where x chr also inactive. More than 2 alleles for a given gene, giving a larger number of genotypes & phenotypes. Any individual still only has two alleles. Parents only have two alleles they can pass to their offspring.
