Beyond Individual Loci

Population genetic models become much more complex when two or more loci are considered simultaneously. Random association of the alleles (and genotypes) at two loci is called gametic equilibrium. Linkage is the primary factor that can cause the alleles at two loci to be in nonrandom association within a population. This is called gametic disequilibrium. Many other factors (e.g., genetic drift, selection, hybridization, etc.) can cause even unlinked loci to be in gametic disequilibrium. The interpretation of multilocus genotypes is becoming increasingly important in conservation because of advances in techniques to screen many loci and advances in data analysis. The ability to sequence large sections of chromosomes provides the opportunity to interpret multiple locus genetic data using entirely new conceptual approaches. It is now possible to use sequence data to identify chromosomal segments originating from different ancestral chromosomes.