Single origin of sex chromosomes and multiple origins of B chromosomes in fish genus Characidium Pansonato-Alves, José Carlos Alves Serrano, Érica Utsunomia, Ricardo Martínez Camacho, Juan Pedro Costa Silva, Guilherme José da Vicari, Marcelo Ricardo Ferreira Artoni, Roberto Oliveira, Cláudio Foresti, Fausto Chromosomes DNA sequence analysis Genome evolution In situ hybridization Phylogenetic analysis Probe hybridization Sex chromosomes W chromosomes Chromosome painting with DNA probes obtained from supernumerary (B) and sex chromosomes in three species of fish genus Characidium (C. gomesi, C. pterostictum and C. oiticicai) showed a close resemblance in repetitive DNA content between B and sex chromosomes in C. gomesi and C. pterostictum. This suggests an intraspecific origin for B chromosomes in these two species, probably deriving from sex chromosomes. In C. oiticicai, however, a DNA probe obtained from its B chromosome hybridized with the B but not with the A chromosomes, suggesting that the B chromosome in this species could have arisen interspecifically, although this hypothesis needs further investigation. A molecular phylogenetic analysis performed on nine Characidium species, with two mtDNA genes, showed that the presence of heteromorphic sex chromosomes in these species is a derived condition, and that their origin could have been unique, a conclusion also supported by interspecific chromosome painting with a CgW probe derived from the W chromosome in C. gomesi. Summing up, our results indicate that whereas heteromorphic sex chromosomes in the genus Characidium appear to have had a common and unique origin, B chromosomes may have had independent origins in different species. Our results also show that molecular phylogenetic analysis is an excellent complement for cytogenetic studies by unveiling the direction of evolutionary chromosome changes. 2014-10-06T06:52:19Z 2014-10-06T06:52:19Z 2014 info:eu-repo/semantics/article Pansonato-Alves, J.C.; et al. Single origin of sex chromosomes and multiple origins of B chromosomes in fish genus Characidium. Plos One, 9(9): e107169 (2014). [http://hdl.handle.net/10481/33350] 1932-6203 http://hdl.handle.net/10481/33350 10.1371/journal.pone.0107169 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ info:eu-repo/semantics/openAccess Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License Public Library of Science (PLOS)