title: B-chromosome frequency stability in Prochilodus lineatus (Characiformes, Prochilodontidae).
abstract: The genus Prochilodus includes individuals ranging in size from medium to large, being highly relevant for commercial and subsistence fishing. Prochilodus species have a diploid number of 2n = 54 chromosomes and up to seven supernumerary (B) microchromosomes. Previous research has shown that B frequency increased drastically in the Mogi-Guaçu river population of Prochilodus lineatus in the early 1980s, whereas it remained about constant in the 1990s. Here we analyses B frequency in this population during the 2003-2007 period and have found that frequency has not changed significantly since 1987, and that these B chromosomes do not show the intra-individual variation in number that characterized them in the 1980s. This indicates that these B chromosomes have been neutralized, after their invasion, through their mitotic stabilization.
authors.affiliation: Departamento Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista (UNESP), Campus de Bauru, Bauru, SP, Brazil.
authors.forename: Tatiana Aparecida
authors.initials: TA
authors.lastname: Voltolin
authors.forename: José Augusto
authors.initials: JA
authors.lastname: Senhorini
authors.forename: Claudio
authors.initials: C
authors.lastname: Oliveira
authors.forename: Fausto
authors.initials: F
authors.lastname: Foresti
authors.forename: Jehud
authors.initials: J
authors.lastname: Bortolozzi
authors.forename: Fabio
authors.initials: F
authors.lastname: Porto-Foresti
mesh_terms: D000818:Animals; D001938:Brazil; D043171:Chromosomal Instability; D002875:Chromosomes / Q000235:genetics*; D019143:Evolution, Molecular; D005399:Fishes / Q000235:genetics*; D040961:Genetic Drift; D014644:Genetic Variation; D016678:Genome; D008938:Mitosis; D012641:Selection, Genetic; D013997:Time Factors