Identifying the location of the major sex determining locus in genetically improved farmed tilapia using BSA-ddRAD sequencing. Tilapia ddRAD

Different major sex-determining loci have been detected in tilapia. The genetically improved farmed tilapia (GIFT) stock, founded from multiple Nile tilapia (Oreochromis niloticus) populations, is a key resource for tilapia aquaculture. The main sex-determining loci present in GIFT fish are unknown. A bulk segregant analysis (BSA) version of double-digest restriction-site associated DNA sequencing (BSA-ddRADseq) was used to detect and position sex-linked single nucleotide polymorphism (SNP) markers in 19 GIFT stock pedigrees and two Stirling stock pedigrees. Phenotypic sex in Stirling families showed strong association with LG1 (previously known), whereas SNPs located in LG23 showed clear association with sex in all 19 GIFT families. No other genomic regions linked to sex-determination were apparent.