Genomic Organization of Repetitive DNA Elements and Its Implications for the Chromosomal Evolution of Channid Fishes (Actinopterygii, Perciformes)

Abstract

Channid fishes, commonly referred to as “snakeheads”, are currently very important in Asian fishery and aquaculture due to the substantial decline in natural populations because of overexploitation. A large degree of chromosomal variation has been found in this family, mainly through the use of conventional cytogenetic investigations. In this study, we analyzed the karyotype structure and the distribution of 7 repetitive DNA sequences in several Channa species from different Thailand river basins. The aim of this study was to investigate the chromosomal differentiation among species and populations to improve upon the knowledge of its biodiversity and evolutionary history. Rearrangements, such as pericentric inversions, fusions and polyploidization, appear to be important events during the karyotypic evolution of this genus, resulting in the chromosomal diversity observed among the distinct species and even among populations of the same species. In addition, such variability is also increased by the genomic dynamism of repetitive elements, particularly by the differential distribution and accumulation of rDNA sequences on chromosomes. This marked diversity is likely linked to the lifestyle of the snakehead fishes and their population fragmentation, as already identified for other fish species. The karyotypic features highlight the biodiversity of the channid fishes and justify a taxonomic revision of the genus Channa, as well as of the Channidae family as a whole, as some nominal species may actually constitute species complexes.

Chromosomal Evolution in the <b><i>Amolops mantzorum</i></b> Species Group (Ranidae; Anura) Narrated by Repetitive DNAs

“…These DNA motifs are usually accumulated in heterochromatic regions, such as centromeres [Cuadrado and Jouve, 2007a [Vanzela et al, 2002;Supiwong et al, 2014;Cioffi et al, 2015], or nucleolus organizing regions (NORs) [Cuadrado and Jouve, 2007b]. In this study, nonrandom location of SSRs was also demonstrated in amphibians.…”

Interregional cytogenetic comparisons in Halichoeres and Thalassoma wrasses (Labridae) of coastal and insular regions of the southwestern Atlantic

“…Repetitive DNAs play an important role in the evolution of fish karyotype (Canapa et al, 2002;Cioffi et al, 2015). Indeed, because of their dynamics, they are associated with karyotype rearrangements and diversification in many groups of Perciformes (Getlekha et al, 2016).…”

What is Speciation Genomics? The roles of ecology, gene flow, and genomic architecture in the formation of species

“…The authors posit that in lepidopterans, chromosomal divergence may involve two phases: first, a transient origin through local adaptation, and second, a stable persistence through differential introgression, and a similar scenario may well play out in other groups as well (Conflitti et al, 2015). In addition to paracentric inversions, high rates of other chromosomal rearrangements such as pericentric inversions, reciprocal translocations, fusions and polyploidization appear to be evolving at high rates in several groups of 'notorious speciators' such as Mimulus (Fishman et al, 2013), fish (Cioffi et al, 2015) and butterflies (Sichova et al, 2015;Arias, Van Belleghem & McMillan, 2016). Remarkably, in a recent comparative study, the number of fixed inversions between closely related species of songbirds was most strongly predicted by whether or not the species overlap in their geographical range (Hooper & Price, 2017).…”