Use of microsatellite loci and AFLP markers to verify gynogenesis and clonal lines in Nile tilapia Oreochromis niloticus L.

To develop an effective system for parentage analysis in gynogenetic and clonal progeny of Nile tilapia, Oreochromis niloticus L., polymorphic microsatellite loci and amplified fragment length polymorphisms (AFLPs) were investigated in several gynogenetic families and clonal lines. Six microsatellite loci were screened in two meiotic gynogenetic families to look for loci with high gene–centromere recombination rates, which can be used to discriminate meiotic from mitotic gynogenetics. Microsatellite loci UNH189 and UNH211 showed 96.7% and 92.0% heterozygosity, respectively, in these families, while other loci showed lower recombination frequencies. Scoring both UNH189 and UNH211 would give a very low probability of an individual meiotic gynogenetic being homozygous for both loci. Multiplex polymerase chain reaction of microsatellite loci was used to verify parentage in four families of mitotic gynogenetics and five fully inbred clonal lines. The genotype of each clonal line should serve as a unique identifier. Twelve AFLP primers were also investigated and 26 diagnostic AFLP bands were identified to follow inheritance in mitotic gynogenetic individuals. Amplified fragment length polymorphisms were found to be effective for this purpose but microsatellites were more appropriate since they are co-dominant, while AFLPs are dominant markers. A multiplex of the microsatellite loci used in this study would be useful for general parental assignment as well as for the analysis of the products of chromosome set manipulations.