Chromosome differentiation patterns during cichlid fish evolution

BMC Genetics

Research Article

Irani A Ferreira¹  Rafael T Nakajima¹  Andréia B Poletto¹  Diogo C Cabral-de-Mello¹  Juliana Mazzuchelli¹  Cesar Martins¹  Heraldo B Ribeiro¹  Thomas D Kocher²  Paulo C Venere³  Mauro Nirchio⁴ 

[1] Departamento de Morfologia, UNESP - Universidade Estadual Paulista, Instituto de Biociências, Botucatu, SP, Brazil;Department of Biology, University of Maryland, 20742, College Park, MD, USA;Instituto Universitário do Araguaia, UFMT - Universidade Federal de Mato Grosso, Pontal do Araguaia, MT, Brazil;Universidad de Oriente, Escuela de Ciencias Aplicadas del Mar, Boca de Rio, Venezuela;

关键词: Chromosome Pair;    Cichlid Fish;    Cytogenetic Mapping;    South American Species;    Ancestral Karyotype;   

DOI  :  10.1186/1471-2156-11-50

 received in 2010-04-18, accepted in 2010-06-15,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundCichlid fishes have been the subject of increasing scientific interest because of their rapid adaptive radiation which has led to an extensive ecological diversity and their enormous importance to tropical and subtropical aquaculture. To increase our understanding of chromosome evolution among cichlid species, karyotypes of one Asian, 22 African, and 30 South American cichlid species were investigated, and chromosomal data of the family was reviewed.ResultsAlthough there is extensive variation in the karyotypes of cichlid fishes (from 2n = 32 to 2n = 60 chromosomes), the modal chromosome number for South American species was 2n = 48 and the modal number for the African ones was 2n = 44. The only Asian species analyzed, Etroplus maculatus, was observed to have 46 chromosomes. The presence of one or two macro B chromosomes was detected in two African species. The cytogenetic mapping of 18S ribosomal RNA (18S rRNA) gene revealed a variable number of clusters among species varying from two to six.ConclusionsThe karyotype diversification of cichlids seems to have occurred through several chromosomal rearrangements involving fissions, fusions and inversions. It was possible to identify karyotype markers for the subfamilies Pseudocrenilabrinae (African) and Cichlinae (American). The karyotype analyses did not clarify the phylogenetic relationship among the Cichlinae tribes. On the other hand, the two major groups of Pseudocrenilabrinae (tilapiine and haplochromine) were clearly discriminated based on the characteristics of their karyotypes. The cytogenetic mapping of 18S ribosomal RNA (18S rRNA) gene did not follow the chromosome diversification in the family. The dynamic evolution of the repeated units of rRNA genes generates patterns of chromosomal distribution that do not help follows the phylogenetic relationships among taxa. The presence of B chromosomes in cichlids is of particular interest because they may not be represented in the reference genome sequences currently being obtained.

【 授权许可】

Unknown   
© Poletto et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.