title: Possible interspecific origin of the B chromosome of Hypsiboas albopunctatus (Spix, 1824) (Anura, Hylidae), revealed by microdissection, chromosome painting, and reverse hybridisation.
abstract: The B chromosome in the hylid Hypsiboas albopunctatus (2n = 22 + B) is small, almost entirely composed of C-positive heterochromatin, and does not pair with any chromosome of the A complement. B probe, obtained by microdissection and DOP-PCR amplification, was used to search for homology between the B and regular chromosomes of H. albopunctatus and of the related species H. raniceps (Cope, 1862). Reverse hybridisation was also carried out in the investigation. The B probe exclusively painted the supernumerary, not hybridising any other chromosomes in H. albopunctatus, but all H. raniceps chromosomes showed small labelling signals. This result might be an indication that differences exist between the repetitive sequences of A and B chromosomes of H. albopunctatus, and that the chromosomes of H. raniceps and the heterochromatin of the B chromosome of H. albopunctatus are enriched with the same type of repetitive DNA. In meiotic preparations, the B labelled about 30% of scored spermatids, revealing a non-mendelian inheritance, and the painted B in micronucleus suggests that the supernumerary is eliminated from germ line cells. Although our results could suggest an interespecific origin of the B at first sight, further analysis on its repetitive sequences is still necessary. Nevertheless, the accumulation of repetitive sequences, detected in another species, even though closely related, remains an intriguing question.
authors.affiliation: UNESP, Universidade Estadual Paulista, Instituto de Biociências, Departamento de Biologia, Av. 24A 1515, 13506-900, Rio Claro, SP, Brazil.
authors.forename: Simone Lilian
authors.initials: SL
authors.lastname: Gruber
authors.affiliation: UESB, Universidade Estadual do Sudoeste da Bahia, Departamento de Ciências Biológicas, Rua José Moreira Sobrinho s/n, Jequiezinho, 45206-190, Jequié, BA, Brazil.
authors.forename: Débora
authors.initials: D
authors.lastname: Diniz
authors.affiliation: UNESP, Universidade Estadual Paulista, Instituto de Biociências, Departamento de Morfologia, Distrito de Rubião Júnior s/n, 18618-970, Botucatu, SP, Brazil.
authors.forename: Patrícia Elda
authors.initials: PE
authors.lastname: Sobrinho-Scudeler
authors.affiliation: UNESP, Universidade Estadual Paulista, Instituto de Biociências, Departamento de Morfologia, Distrito de Rubião Júnior s/n, 18618-970, Botucatu, SP, Brazil.
authors.lastname: Fausto Foresti
authors.affiliation: UNESP, Universidade Estadual Paulista, Instituto de Biociências, Departamento de Zoologia, Av. 24A 1515, 13506-900, Rio Claro, SP, Brazil.
authors.forename: Célio Fernando Baptista
authors.initials: CF
authors.lastname: Haddad
authors.affiliation: UNESP, Universidade Estadual Paulista, Instituto de Biociências, Departamento de Biologia, Av. 24A 1515, 13506-900, Rio Claro, SP, Brazil.
authors.forename: Sanae
authors.initials: S
authors.lastname: Kasahara
keywords: FISH; GISH; Hylidae family; Supernumerary chromosome; heterochromatin; repetitive DNA; replication banding