Comparative analysis of sex chromosomes in Leporinus species (Teleostei, Characiformes) using chromosome painting

Patrícia Parise-Maltempi,Willem Rens,Patricia Cm O’Brien,Vladimir Trifonov,Edson Da Silva,Malcolm A Ferguson-Smith,Frances Dearden

doi:10.1186/1471-2156-14-60

Abstract

BackgroundThe Leporinus genus, belonging to the Anostomidae family, is an interesting model for studies of sex chromosome evolution in fish, particularly because of the presence of heteromorphic sex chromosomes only in some species of the genus. In this study we used W chromosome-derived probes in a series of cross species chromosome painting experiments to try to understand events of sex chromosome evolution in this family.ResultsW chromosome painting probes from Leporinus elongatus, L. macrocephalus and L. obtusidens were hybridized to each others chromosomes. The results showed signals along their W chromosomes and the use of L. elongatus W probe against L. macrocephalus and L. obtusidens also showed signals over the Z chromosome. No signals were observed when the later aforementioned probe was used in hybridization procedures against other four Anostomidae species without sex chromosomes.ConclusionsOur results demonstrate a common origin of sex chromosomes in L. elongatus, L. macrocephalus and L. obtusidens but suggest that the L. elongatus chromosome system is at a different evolutionary stage. The absence of signals in the species without differentiated sex chromosomes does not exclude the possibility of cryptic sex chromosomes, but they must contain other Leporinus W sequences than those described here.

Highlights

The Leporinus genus, belonging to the Anostomidae family, is an interesting model for studies of sex chromosome evolution in fish, because of the presence of heteromorphic sex chromosomes only in some species of the genus
Hybridisation using Leporinus elongatus W probe (WLe) The WLe probe used against chromosomes of the Leporinus elongatus female painted the entire W chromosome (Figure 1a)
In male individuals of L. macrocephalus the WLe probe painted almost all of both Z chromosomes (Figure 1d)

Summary

Introduction

The Leporinus genus, belonging to the Anostomidae family, is an interesting model for studies of sex chromosome evolution in fish, because of the presence of heteromorphic sex chromosomes only in some species of the genus. Sex chromosomes evolve from an autosomal pair [1], over time they become different both in gene content and structure [2]. Within the fish species with genetic sex determination many variations have been found, ranging from male or female heterogamety to polygenic sex determination. This, together with the fact that even between closely related fish species the sex determination mechanisms can be different [6,9,10,11,12,13], demonstrates the high evolutionary plasticity of this fundamental process [7]

Methods

Results

Conclusion