Selfing reduces heterozygosity by:
Selfing systematically reduces heterozygosity because segregation from heterozygous parent yields one quarter AA, one half Aa, one quarter aa. Only half offspring remain heterozygous, halving H each generation. Formal relationship Ht equals H zero times one half to power t, where t number selfing generations, independent of allele frequencies for loci not under selection. After first selfing heterozygosity 50 percent, after second 25 percent, after six cycles about 1.6 percent. Inbreeding coefficient F rises reciprocally approaching 0.99 after six generations. This principle underpins extraction of recombinant inbred lines by single seed descent, development of near-isogenic lines and fixation of transgenes. Prediction allows breeders to schedule required selfing generations to achieve sufficient homozygosity for varietal stability and DUS testing. This understanding supports competitive exam preparation for NEET, GATE and CSIR NET concepts linking genotype with phenotype through molecular pathways involving transcription factors, hormones and metabolic enzymes that regulate development, adaptation and reproductive biology in applied breeding programs.
Ref: Hartl & Clark Principles Population Genetics selfing reduction; Falconer Introduction Quantitative Genetics; NCBI Bookshelf Heterozygosity equation.