Bulked segregant analysis (BSA) is a technique used to identify genetic markers associated with a mutant phenotype. This allows geneticists to discover genes conferring certain traits of interest, such as disease resistance or susceptibility.
This technique involves forming two groups that display opposing phenotypes for a trait of interest. For example, the individuals in one group are resistant to a disease, whereas those in the second group are not. Two bulked DNA samples are then created by pooling the DNA of all individuals in each group.
These two bulked samples can then be analysed using techniques such as Restriction fragment length polymorphism or RAPD to detect similarities and differences in the various loci of the genome. The two groups will have a random distribution of alleles in all loci of the genome except for loci that are associated with the mutation.[1] A consistent difference on a locus between the two bulked samples likely means that the locus is associated with the mutation of interest.