IMED2004 Study Guide - Final Guide: Gene Mapping, Chromosome, Meiosis
Document Summary
Gene a to b = 5 m. u gene b to c = 10 m. u. Then a to c = 15 m. u. C and d exhibit greatest recombination c and d furthest apart, with a and b between them. Using recombination frequencies and remembering 1 m. u. Hence between a and c = 15 m. u. C and d furthest apart on chromosome bc most recomb happening (highest recomb freq %) Hence, can work out position of loci and how far apart they are on chromosome. Cannot distinguish between genes on different chromosomes and genes located far apart on same chromosome. Can say they belong to different groups of linked genes (linkage groups) On different chromosomes or far apart on same chromosome. Testcross for two genes that are far apart underestimates true physical distance. A double crossover occurs when two separate recomb events take place between two loci. Once we see 50% of recomb, they belong to diff linkage groups.
