Delimiting the Origin of a B Chromosome by FISH Mapping, Chromosome Painting and DNA Sequence Analysis in Astyanax paranae (Teleostei, Characiformes) Silva, Duílio M. Z. de A. Pansonato-Alves, José Carlos Utsunomia, Ricardo Araya-Jaime, Cristian Ruiz-Ruano, Francisco J. Natal Daniel, Sandro Teruo Hashimoto, Diogo Oliveira, Cláudio Martínez Camacho, Juan Pedro Porto-Foresti, Fábio Foresti, Fausto Chromosome mapping Chromosomes DNA DNA sequence analysis Fungal genomics Histones Sex chromosomes Supernumerary (B) chromosomes have been shown to contain a wide variety of repetitive sequences. For this reason, fluorescent in situ hybridisation (FISH) is a useful tool for ascertaining the origin of these genomic elements, especially when combined with painting from microdissected B chromosomes. In order to investigate the origin of B chromosomes in the fish species Astyanax paranae, these two approaches were used along with PCR amplification of specific DNA sequences obtained from the B chromosomes and its comparison with those residing in the A chromosomes. Remarkably, chromosome painting with the one-arm metacentric B chromosome probe showed hybridization signals on entire B chromosome, while FISH mapping revealed the presence of H1 histone and 18S rDNA genes symmetrically placed in both arms of the B chromosome. These results support the hypothesis that the B chromosome of A. paranae is an isochromosome. Additionally, the chromosome pairs Nos. 2 or 23 are considered the possible B chromosome ancestors since both contain syntenic H1 and 18S rRNA sequences. The analysis of DNA sequence fragments of the histone and rRNA genes obtained from the microdissected B chromosomes showed high similarity with those obtained from 0B individuals, which supports the intraspecific origin of B chromosomes in A. paranae. Finally, the population hereby analysed showed a female-biased B chromosome presence suggesting that B chromosomes in this species could influence sex determinism. 2014-05-29T07:37:08Z 2014-05-29T07:37:08Z 2014 info:eu-repo/semantics/article Silva, D.M.Z. de A.; et al. Delimiting the Origin of a B Chromosome by FISH Mapping, Chromosome Painting and DNA Sequence Analysis in Astyanax paranae (Teleostei, Characiformes). Plos One, 9(4): e94896 (2014). [http://hdl.handle.net/10481/32021] 1932-6203 http://hdl.handle.net/10481/32021 10.1371/journal.pone.0094896 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)