Topic 3

Non-random genotypic, and hence allelic associations among loci (if there are 2 loci, nonrandom genotypic associations b/w 2 loci)

Random segregation: alleles at a single locus segregate randomly, offspring have a 50% chance of inheriting each of a parent’s alleles (basis for H-W eq’m)

Independently Segregation: Alleles at different loci segregate independently, so that the inheritance of alleles at locus A is independent of the inheritance of alleles at locus B • ->otherwise, results in gametic diseq’m (or linkage diseq’m) • ->law holds true, if loci are located on different chromosomes • ->if loci close together on the same chromosome, , will often be inherited as a single ‘unit’

Gametic diseq’m is a broa term which include many reasons that can result in non random allelic and genotypic association among loci - includes linkage diseq'm - also includes migration, selection, genetic drift, etc

process by which 4 haploid gametes are produced from a diploid parent cell (located in gonads)

The process by which sister chromosomes (not chromatids) can exchange pieces of DNA during meiosis by crossing over

AB+ab=AaBb

Ab+aB=AaBb

the fraction of recombinant gametes an individual produces

• 0.25 to 0.25 1) D=0, there is no gametic disequilibrium

0-0.5 1) r=0: never any recombination 2) r=0.5: loci so far apart that they may as well be on different chromosomes (there will be no linkage disequilibrium)