Tracking the Evolutionary Trends Among Small-Size Fishes of the Genus Pyrrhulina (Characiforme, Lebiasinidae): New Insights From a Molecular Cytogenetic Perspective

Abstract

Miniature fishes have always been a challenge for cytogenetic studies due to the difficulty in obtaining chromosomal preparations, making them virtually unexplored. An example of this scenario relies on members of the family Lebiasinidae which include miniature to medium-sized, poorly known species, until very recently. The present study is part of undergoing major cytogenetic advances seeking to elucidate the evolutionary history of lebiasinids. Aiming to examine the karyotype diversification more deeply in Pyrrhulina, here we combined classical and molecular cytogenetic analyses, including Giemsa staining, C-banding, repetitive DNA mapping, comparative genomic hybridization (CGH), and whole chromosome painting (WCP) to perform the first analyses in five Pyrrhulina species (Pyrrhulina aff. marilynae, Pyrrhulina sp., P. obermulleri, P. marilynae and Pyrrhulina cf. laeta). The diploid number (2n) ranged from 40 to 42 chromosomes among all analyzed species, but P. marilynae is strikingly differentiated by having 2n = 32 chromosomes and a karyotype composed of large meta/submetacentric chromosomes, whose plesiomorphic status is discussed. The distribution of microsatellites does not markedly differ among species, but the number and position of the rDNA sites underwent significant changes among them. Interspecific comparative genome hybridization (CGH) found a moderate divergence in the repetitive DNA content among the species’ genomes. Noteworthy, the WCP reinforced our previous hypothesis on the origin of the X1X2Y multiple sex chromosome system in P. semifasciata. In summary, our data suggest that the karyotype differentiation in Pyrrhulina has been driven by major structural rearrangements, accompanied by high dynamics of repetitive DNAs.

Integrating Cytogenetics and Population Genomics: Allopatry and Neo-Sex Chromosomes May Have Shaped the Genetic Divergence in the Erythrinus erythrinus Species Complex (Teleostei, Characiformes)

“…Comparative genomic hybridization (CGH) experiments were performed as described [ 28 ] with adaptations of probe/C 0 t-1 DNA ratio based on previous studies [ 28 , 29 , 30 ]. Male genomic probes from all populations were co-hybridized to the male chromosomes of populations A1 and D separately.…”

The Genetic Differentiation of Pyrrhulina (Teleostei, Characiformes) Species is Likely Influenced by Both Geographical Distribution and Chromosomal Rearrangements

“…The subfamily Pyrrhulininae is the most diverse, including the genera Derhamia, Nannostomus, Copella, Copeina, and Pyrrhulina ( Fricke et al, 2021 ). Recent cytogenetic and molecular data have added significant contributions to understanding evolutionary relationships of these genera ( Moraes et al, 2017 , 2019 , 2021 ; Sassi et al, 2019 ; Toma et al, 2019 ; Sember et al, 2020 ). Particularly, concerning Pyrrhulina , its diploid number (2n) ranges from 32 to 42 chromosomes, with Pyrrhulina aff.…”

“…Differently from the others, P. semifasciata ( Steindachner, 1876 ) has divergent 2n among sexes (2n = ♀42 and ♂41) due to its exclusive multiple ♀X 1 X 1 X 2 X 2 /♂X 1 X 2 Y sex chromosome system ( Moraes et al, 2017 ; Moraes et al, 2019 ). In addition, P. marilynae ( Netto-Ferreira and Marinho, 2013 ) also differs from its congeneric species having 2n = 32 chromosomes, due to a series of chromosomal fusions ( Moraes et al, 2021 ).…”

Karyotype Evolution of Talking Thorny Catfishes Anadoras (Doradidae, Astrodoradinae): A Process Mediated by Structural Rearrangements and Intense Reorganization of Repetitive DNAs

“…Neotropical freshwater fishes represent one of the most diversified animal groups on earth due to their remarkable morphological and chromosomal diversity, and they are considered an excellent model for evolutionary studies [Machado et al, 2018;de Moraes et al, 2021;Favarato et al, 2021;Sassi et al, 2021;Takagui et al, 2021]. Over the past years, comparative cytogenetic studies have generated relevant information that contributes to the understanding of phylogenetic relationships, taxonomy, and diversification of some Brazilian freshwater fish lineages [Ferreira et al, 2017[Ferreira et al, , 2020Prizon et al, 2017;Usso et al, 2018].…”