Identification of a sex-determining region in Nile tilapia (Oreochromis niloticus) using bulked segregant analysis.
Sex determination in the Nile tilapia (Oreochromis niloticus) is thought to be an XX-XY (male heterogametic) system controlled by a major gene. We searched for DNA markers linked to this major locus using bulked segregant analysis. Ten microsatellite markers belonging to linkage group 8 were found to be linked to phenotypic sex. The putative Y-chromosome alleles correctly predict the sex of 95% of male and female individuals in two families. Our results suggest a major sex-determining locus within a few centimorgans of markers UNH995 and UNH104. A third family from the same population showed no evidence for linkage of this region with phenotypic sex, indicating that additional genetic and/or environmental factors regulate sex determination in some families. These markers have immediate utility for studying the strength of different Y chromosome alleles, and for identifying broodstock carrying one or more copies of the Y haplotype.
D000818:Animals; D002874:Chromosome Mapping; D005260:Female; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics*; D019849:Sex Determination Processes; D012744:Sex Ratio; D017210:Tilapia / Q000235:genetics* / Q000502:physiology; D014998:Y Chromosome / Q000235:genetics*