Article

Structure and Sequence of the Sex Determining Locus in Two Wild Populations of Nile Tilapia

Citation

Triay C, Conte MA, Baroiller J, Bezault E, Clark FE, Penman DJ, Kocher TD & D'Cotta H (2020) Structure and Sequence of the Sex Determining Locus in Two Wild Populations of Nile Tilapia. Genes, 11 (9), Art. No.: 1017. https://doi.org/10.3390/genes11091017

Abstract
In domesticated strains of the Nile tilapia, phenotypic sex has been linked to genetic variants on linkage groups 1, 20 and 23. This diversity of sex-loci might reflect a naturally polymorphic sex determination system in Nile tilapia, or it might be an artefact arising from the process of domestication. Here, we searched for sex-determiners in wild populations from Kpandu, Lake Volta (Ghana-West Africa), and from Lake Koka (Ethiopia-East Africa) that have not been subjected to any genetic manipulation. We analysed lab-reared families using double-digest Restriction Associated DNA sequencing (ddRAD) and analysed wild-caught males and females with pooled whole-genome sequencing (WGS). Strong sex-linked signals were found on LG23 in both populations, and sex-linked signals with LG3 were observed in Kpandu samples. WGS uncovered blocks of high sequence coverage, suggesting the presence of B chromosomes. We confirmed the existence of a tandem amh duplication in LG23 in both populations and determined its breakpoints between the oaz1 and dot1l genes. We found two common deletions of ~5 kb in males and confirmed the presence of both amhY and amh∆Y genes. Males from Lake Koka lack both the previously reported 234 bp deletion and the 5 bp frameshift-insertion that creates a premature stop codon in amh∆Y.

Keywords
sex-determinant; Y-chromosome; amh; male duplication; Nile tilapia

Journal
Genes: Volume 11, Issue 9

StatusPublished
FundersThe Agence Nationale de la Recherche / French National Research Agency (ANR)
Publication date30/09/2020
Publication date online31/08/2020
Date accepted by journal27/08/2020
URLhttp://hdl.handle.net/1893/31723
eISSN2073-4425