Chromosomal Evolution in Aspredinidae (Teleostei, Siluriformes): Insights on Intra- and Interspecific Relationships with Related Groups

In this study, conventional and molecular cytogenetic studies coupled with nucleotide sequencing were performed in 6 Aspredininae species (Amaralia hypsiura,Bunocephalus cf.aloikae,Bunocephalus amaurus,Bunocephalus aff.coracoideus,Bunocephalus verrucosus, andPlatystacus cotylephorus) from different locations of the Amazon hydrographic basin. Our results showed highly divergent diploid numbers (2n) among the species, ranging from 49 to 74, including the occurrence of an XX/X0 sex chromosome system. A neighbor-joining phylogram based on the cytochromec oxidase I (COI) showed thatBunocephalus coracoideus is not a monophyletic clade, but closely related toB. verrucosus. The karyotypic data associated withCOI suggest an ancestral karyotype for Aspredinidae with a reduced 2n, composed of bi-armed chromosomes and a trend toward chromosomal fissions resulting in higher diploid number karyotypes, mainly composed of acrocentric chromosomes. Evolutionary relationships were discussed under a phylogenetic context with related species from different Siluriformes families. The karyotype features and chromosomal diversity of Aspredinidae show an amazing differentiation, making this family a remarkable model for investigating the evolutionary dynamics in siluriforms as well as in fish as a whole.Cytogenet Genome Res

Source: Cytogenetic and Genome Research - November 23, 2020 Category: Genetics & Stem Cells Source Type: research