Reconstruction of the Doradinae (Siluriformes-Doradidae) ancestral diploid number and NOR pattern reveals new insights about the karyotypic diversification of the Neotropical thorny catfishes

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

“…Based on this scenario of karyotype homogeneity, Eler et al [2007] and Milhomem et al [2008] proposed a model of chromosome diversification mediated by pericentric inversion events, due to the constancy of 2n = 58 and great variation in karyotype formulas. Recently, this scenario changed drastically, revealing numeric and structural variations in several thorny catfishes, besides supernumerary chromosomes and a unique ZW sexual system [Takagui et al, 2017[Takagui et al, , 2021Baumgärtner et al, 2018]. According to Takagui et al [2021], the ancestral diploid number for the Doradidae family still remains as an open question, but several lines of evidence support the 2n = 58 chromosomes as a plesiomorphic feature in the family and as the likely ancestral karyotype configuration.…”

“…Recently, this scenario changed drastically, revealing numeric and structural variations in several thorny catfishes, besides supernumerary chromosomes and a unique ZW sexual system [Takagui et al, 2017[Takagui et al, , 2021Baumgärtner et al, 2018]. According to Takagui et al [2021], the ancestral diploid number for the Doradidae family still remains as an open question, but several lines of evidence support the 2n = 58 chromosomes as a plesiomorphic feature in the family and as the likely ancestral karyotype configuration. Furthermore, this diploid number also occurs in most species of Auchenipteridae [Lui et al, 2009[Lui et al, , 2010[Lui et al, , 2013a[Lui et al, , 2013b[Lui et al, , 2015[Lui et al, , 2021Felicetti et al, 2021;Machado et al, 2021;Santos et al, 2021], the sister group to Doradidae family [Arce et al, 2013;Birindelli, 2014;Sabaj and Arce, 2021].…”

“…Pericentric inversions have been frequently detected in many groups of fish, especially among the Siluriformes where they are considered the major rearrangements in the karyotype diversification in Loricariichthys [Takagui et al, 2014], Rineloricaria [Venturelli et al, 2021], Trachelyopterus [Santos et al, 2021], Tatia [Lui et al, 2013a], Pimelodus [Girardi et al, 2018], and Trichomycterus [Oliveira et al, 2016]. Among Doradidae, multiple pericentric inversions events associated with heterochromatin movements occurred independently in several clades and played a key role in the diversification of Wertheimerinae [Eler et al, 2007;Takagui et al, 2019] and Doradinae subfamilies, especially in the large species allocated in the nonfimbriated barbels clade [Milhomem et al, 2008;Baumgärtner et al, 2018;Takagui et al, 2021] and in the widespread species T. paraguayensis [Baumgärtner et al, 2016].…”

“…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].…”