Research Paper

Reviews in Fish Biology and Fisheries

, Volume 23, Issue 2, pp 201-214

First online:

Chromosomal evolution of neotropical cichlids: the role of repetitive DNA sequences in the organization and structure of karyotype

  • Carlos Henrique SchneiderAffiliated withLaboratório de Genética Animal, Instituto Nacional de Pesquisas da Amazônia (INPA) Email author 
  • , Maria Claudia GrossAffiliated withLaboratório de Citogenômica, Departamento de Biologia, Instituto de Ciências Biológicas, Universidade Federal do Amazonas
  • , Maria Leandra TerencioAffiliated withLaboratório de Genética Animal, Instituto Nacional de Pesquisas da Amazônia (INPA)
  • , Roberto Ferreira ArtoniAffiliated withLaboratório de Citogenética e Evolução, Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa
  • , Marcelo Ricardo VicariAffiliated withLaboratório de Citogenética e Evolução, Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa
  • , Cesar MartinsAffiliated withLaboratório de Genômica Integrativa, Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP)
  • , Eliana FeldbergAffiliated withLaboratório de Genética Animal, Instituto Nacional de Pesquisas da Amazônia (INPA)

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Abstract

Cichlids are important in the aquaculture and ornamental fish trade and are considered models for evolutionary biology. However, most studies of cichlids have investigated African species, and the South American cichlids remain poorly characterized. Studies in neotropical regions have focused almost exclusively on classical cytogenetic approaches without investigating physical chromosomal mapping of specific sequences. The aim of the present study is to investigate the genomic organization of species belonging to different tribes of the subfamily Cichlinae (Cichla monoculus, Astronotus ocellatus, Geophagus proximus, Acaronia nassa, Bujurquina peregrinabunda, Hoplarchus psittacus, Hypselecara coryphaenoides, Hypselecara temporalis, Caquetaia spectabilis, Uaru amphiacanthoides, Pterophyllum leopoldi, Pterophyllum scalare, and Symphysodon discus) and reexamine the karyotypic evolutionary patterns proposed for this group. Variations in some cytogenetic markers were observed, although no trends were found in terms of the increase, decrease, or maintenance of the basal diploid chromosome number 2n = 48 in the tribes. Several species were observed to have 18S rDNA genetic duplications, as well as multiple rDNA loci. In most of the taxa analyzed, the 5S rDNA was located in the interstitial region of a pair of homologous chromosomes, although variations from this pattern were observed. Interstitial telomere sites were also observed and appear to be involved in chromosomal rearrangement events and the accumulation of repeat-rich satellite DNA sequences. Our data demonstrated the karyotypic diversity that exists among neotropical cichlids, suggesting that most of this diversity is due to the repetitive sequences present in heterochromatic regions and that repeat sequences have greatly influenced the karyotypic evolution of these fishes.

Keywords

Karyotype evolution Interstitial telomeric sites Fluorescent in situ hybridization Ribosomal DNA