A swimy locus on Y chromosome of the platyfish (Xiphophorus maculatus) is derived from a novel DNA transposon Zisupton

A swimy locus derived from a novel DNA transposon Zisupton was located on the sex determination region (SD) of Xiphophorus maculatus. The analysis of expression pattern showed that swimy was exclusively expressed in adult testis in X. maculatus. The putative 939 aa sequence contains four Zn-finger domains, such as two C2H2 type, one NFX type and one SWIM type Zn-finger domain, and one SAP DNA-binding domain. Swimy has about 7 copies per haploid X. maculatus genome with Y-specific copies located in the SD region, and become the second new W-linked marker of platyfish. Analysis of the structure and distribution of this sex-linked marker is benefit to shed new light on the evolutionary dynamics of sex chromosomes in fish. (C) 2012 Elsevier B.V. All rights reserved.