Identification of sex determination gene(s) through comparative sequence analysis of X and Y chromosomes in channel catfish

Abstract

One of the most fundamental and fascinating processes of life is the determination of sex. Scientists have worked for hundreds of years to understand the mechanism of sex determination in the fields of developmental and evolutionary biology. In teleost, sex determination system exhibits surprisingly diverse and plasticity during evolution.

Catfish has a XY male/XX female sex determination system, but the exact mechanism of its sex determination is unknown at present. As a first step toward the identification of sex determining gene(s) in catfish, we generated the first genome sequence assembly of the YY catfish using next-generation sequencing. This allowed the generation of the Y-chromosome sequences. QTL mapping and GWAS analysis were conducted to locate the sex determination locus to linkage group 4. Comparative analysis of X chromosome and Y chromosome sequences was performed to determine the similarity and differences of the sex chromosomes with respect to chromosome size, sequence identities, gene contents and expression patterns of their genes during early gonad development. This project would lay the foundation for further downstream analysis of genes involved in sex determination and differentiation in catfish.