Identification of a sex-determining region in Nile tilapia (Oreochromis niloticus) using bulked segregant analysis

Anim Genet. 2003 Oct;34(5):379-83. doi: 10.1046/j.1365-2052.2003.01035.x.


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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Chromosome Mapping*
  • Female
  • Male
  • Microsatellite Repeats / genetics*
  • Sex Determination Processes*
  • Sex Ratio
  • Tilapia / genetics*
  • Tilapia / physiology
  • Y Chromosome / genetics*