title: Chromosome banding in three species of Hypsiboas (Hylidae, Hylinae), with special reference to a new case of B-chromosome in anuran frogs and to the reduction of the diploid number of 2n = 24 to 2n = 22 in the genus.
abstract: The chromosomes of hylids Hypsiboas albopunctatus, H. raniceps, and H. crepitans from Brazil were analyzed with standard and differential staining techniques. The former species presented 2n = 22 and 2n = 23 karyotypes, the odd diploid number is due to the presence of an extra element interpreted as B chromosome. Although morphologically very similar to the small-sized chromosomes of the A complement, the B was promptly recognized, even under standard staining, on the basis of some characteristics that are usually attributed to this particular class of chromosomes. The two other species have 2n = 24, which is the chromosome number usually found in the species of Hypsiboas karyotyped so far. This means that 2n = 22 is a deviant diploid number, resulted from a structural rearrangement, altering the chromosome number of 2n = 24 to 2n = 22. Based on new chromosome data, some possibilities were evaluated for the origin of B chromosome in Hypsiboas albopunctatus, as well as the karyotypic evolution in the genus, leading to the reduction in the diploid number of 2n = 24 to 2n = 22.
authors.affiliation: Departamento de Biologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Av. 24A, 1515, 13506-900 Rio Claro, SP, Brasil.
authors.forename: Simone Lilian
authors.initials: SL
authors.lastname: Gruber
authors.forename: Célio Fernando Baptista
authors.initials: CF
authors.lastname: Haddad
authors.forename: Sanae
authors.initials: S
authors.lastname: Kasahara
mesh_terms: D000818:Animals; D001001:Anura / Q000235:genetics*; D002871:Chromosome Banding; D020223:Chromosome Painting; D002875:Chromosomes / Q000648:ultrastructure*; D020732:Cytogenetic Analysis; D004171:Diploidy; D005260:Female; D007621:Karyotyping; D008297:Male; D012730:Sex Chromosomes; D013045:Species Specificity