Practice question

Simple sequence repeats are codominant markers detecting both alleles at a locus simultaneously as distinct fragment sizes separated by gel or capillary electrophoresis. Homozygous individuals display a single band corresponding to identical repeat length on both homologous chromosomes, while heterozygous individuals show two bands of different lengths, one inherited from each parent. This ability supports accurate allele frequency calculation, heterozygosity estimation and linkage mapping studies. Dominant systems such as RAPD, AFLP and ISSR produce presence-absence profiles that completely mask heterozygosity, limiting genetic information.