IMED2004 Study Guide - Final Guide: Chromosome, Mendelian Inheritance, Genetic Linkage
Document Summary
A single crossover produces combinations of alleles not present on parental chromosomes. A 2nd crossover between same two genes reverses effect. Cannot distinguish between progeny produced by double crossover and no crossover. Linkage of 2 loci a and b. At each of those loci, have 2 alleles, large a and b. And in blue have small a and b. Single cross over between a and b. If have second crossover, it will reverse effects of first crossover. Large a with b and small a and b. Loci doesn"t look like have recombination bc big with big, small with small. Produce recombinant gametes, but not detecting that recomb event. Tells us we have good spread of markers = underestimate distance. Freq a and b & a and c, is 50%, therefore independent assortment. May be on different chr. or very far apart:
