MBG 2040 Study Guide - Midterm Guide: Prophase, Galactose, Deoxyribonuclease

• School: University of Guelph
• Department: Molecular Biology and Genetics
• Course: MBG 2040
• Professor: Jim Uniacke

Document Summary

Assumption: if trait is rare and autosomal recessive, then individuals that marry into pedigree are homozygous for the normal allele (unless evidence to contrary) Recessive mutations involve loss of gene function: null/amorphic alleles nonfunctional protein or no protein produced, hypomorphic alleles poorly function protein or reduced amount of normal function protein. For pedigrees : (cid:862)o(cid:396)(cid:863) (cid:373)ea(cid:374)s add, (cid:862)a(cid:374)d(cid:863) (cid:373)ea(cid:374)s multiply finding possible genotypes knowing an individual is unaffected: do all possible combinations in steps. First write down the combination (ex: 1/3 aa x 1/2 aa). Second, do a quick cross (aa x aa), you get (1/2 aa, 1/2. Multiply the combination fractions (1/3 x 1/2 = 1/6). Then multiply each cross fraction by the combination fraction [ 1/6 (1/2 aa, 1/2 aa) ]. Do this same thing for each possible combination depending on pa(cid:396)e(cid:374)ts(cid:859) possible genotypes. Remember if you know the individual is unaffected, eliminate the 1/4aa option.