Linkage, Recombination and Genetic Mapping
Linkage, Recombination and Genetic Mapping
甲工 2 Male Female 巴日 Hemophilia a Hemophilia B Colorblind Hemophilic and 34 田田 colorblind
Linkage: Alleles of two genes segregate together during meiosis. W y >1/4 1144 1/2 114 +y 114 y W十 1/2 w y W 114 >114 //hWy Complete Linkage Partial Linkage No Linkage
Linkage: Alleles of two genes segregate together during meiosis. + + w y w w y y + + + + w w y y + + + + + + w y Complete Linkage Partial Linkage No Linkage 1/2 1/2 1/4 1/4 1/4 1/4 >1/4 >1/4 <1/4 <1/4
During meiosis crossing over between homologous chromosomes produces recombinant chromosomes
• During meiosis crossing over between homologous chromosomes produces recombinant chromosomes A a b B A a B b
The frequency of recombinant gametes is 12 the frequency of crossing over a b b b a B A B A b A B A B Each crossover event gives rise to two recombinant and two parental chromosomes. A crossover frequency of 100% gives a recombinant chromosome frequency of 50%
The frequency of recombinant gametes is 1/2 the frequency of crossing over • Each crossover event gives rise to two recombinant and two parental chromosomes. • A crossover frequency of 100% gives a recombinant chromosome frequency of 50%. a b a b A B A B a b a B A b A B