Cytogenetics, genomics and biodiversity of the South American and African Arapaimidae fish family (Teleostei, Osteoglossiformes)

• Published in: PLOS ONE
• Main Authors: Oliveira, Ezequiel Aguiar de, Bertollo, Luiz Antônio Carlos, Ráb, Petr, Ezaz, Tariq Tariq, Yano, Cassia Fernanda, Hatanaka, Terumi, Jegede, Oladele Ilesanmi, Tanomtong, Alongklod, Liehr, Thomas, Sember, Alexandr, Maruyama, Sandra R., Feldberg, Eliana, Viana, Patrik Ferreira, Cioffi, Marcelo de Bello
• Format: Article in Journal/Newspaper
• Language: English
• Published: PLoS ONE 2019
• Subjects: Dna 18s; Dna 5s; Repetitive Dna; Ribosome Dna; Acrocentric Chromosome; Africa; Allele; Animals Cell; Animals Tissue; Arapaima; Arapaima Gigas; Biodiversity; C Banding; Chromosomal Mapping; Chromosome Analysis; Chromosome Number; Comparative Genomic Hybridization; Controlled Study; Diploidy; Dna Content; Evolution; Female; In Situ Hybridization; Fluorescence; Genetic Distance; Genetic Variability; Genomics; Genotype; Heterotis Niloticus; Karyotype; Male; Nonhuman; Osteoglossiformes; Principal Component Analysis; Polymorphism; Single Nucleotide; South America; Teleost; Animals; Classification; Fish; Genetics; Genome; South Africa; Animalss; Ribosomal Dna; Fishes; Antarc*; Antarctica
• Online Access: https://repositorio.inpa.gov.br/handle/1/14643; https://doi.org/10.1371/journal.pone.0214225

Osteoglossiformes represents one of the most ancestral teleost lineages, currently widespread over almost all continents, except for Antarctica. However, data involving advanced molecular cytogenetics or comparative genomics are yet largely limited for this fish group. Therefore, the present investigations focus on the osteoglossiform family Arapaimidae, studying a unique fish model group with advanced molecular cytogenetic genomic tools. The aim is to better explore and clarify certain events and factors that had impact on evolutionary history of this fish group. For that, both South American and African representatives of Arapaimidae, namely Arapaima gigas and Heterotis niloticus, were examined. Both species differed markedly by diploid chromosome numbers, with 2n = 56 found in A. gigas and 2n = 40 exhibited by H. niloticus. Conventional cytogenetics along with fluorescence in situ hybridization revealed some general trends shared by most osteoglossiform species analyzed thus far, such as the presence of only one chromosome pair bearing 18S and 5S rDNA sites and karyotypes dominated by acrocentric chromosomes, resembling thus the patterns of hypothetical ancestral teleost karyotype. Furthermore, the genomes of A. gigas and H. niloticus display remarkable divergence in terms of repetitive DNA content and distribution, as revealed by comparative genomic hybridization (CGH). On the other hand, genomic diversity of single copy sequences studied through principal component analyses (PCA) based on SNP alleles genotyped by the DArT seq procedure demonstrated a very low genetic distance between the South American and African Arapaimidae species; this pattern contrasts sharply with the scenario found in other osteoglossiform species. Underlying evolutionary mechanisms potentially explaining the obtained data have been suggested and discussed. © 2019 de Oliveira et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.