fshr: a fish sex-determining locus shows variable incomplete penetrance across flathead grey mullet populations

• Published in: iScience Vol. 24; no. 1; p. 101886
• Main Authors: Ferraresso, Serena, Bargelloni, Luca, Babbucci, Massimiliano, Cannas, Rita, Follesa, Maria Cristina, Carugati, Laura, Melis, Riccardo, Cau, Angelo, Koutrakis, Manos, Sapounidis, Argyrios, Crosetti, Donatella, Patarnello, Tomaso
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 22-01-2021; Elsevier
• Subjects: Evolutionary Biology; Genetics; Genomics; Evolutionary Biology; Genetics; Genomics
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2020.101886

Whole-genome sequencing data were produced from a single flathead grey mullet female and assembled into a draft genome sequence, whereas publicly available sequence data were used to obtain a male draft sequence. Two pools, each consisting of 60 unrelated individuals, respectively, of male and female fish were analyzed using Pool-Sequencing. Mapping and analysis of Pool-Seq data against the draft genome(s) revealed >30 loci potentially associated with sex, the most promising locus of which, encoding the follicle-stimulating hormone receptor (fshr) and harboring two missense variants, was genotyped on 245 fish from four Mediterranean populations. Genotype data showed that fshr represents a previously unknown sex-determining locus, although the incomplete association pattern between fshr genotype and sex-phenotype, the variability of such pattern across different populations, and the presence of other candidate loci reveal that a greater complexity underlies sex determination in the flathead grey mullet.
[Display omitted]
•Three SNPs with sex-specific allele frequencies found in the grey mullet fshr gene•Two missense variants at the fshr locus are significantly associated with male sex•fshr male genotypes show divergent distribution across geographical populations•Incomplete penetrance of fshr variants suggests that additional factors exist
Genetics; Evolutionary Biology; Genomics