Abstract
We report on the presence of B-chromosomes in two populations of Dendropsophus nanus (= Hyla nana Boulenger, 1889) from Sao Paulo State, Brazil. Such chromosomes were observed in 4 out of 43 specimens (9.3%) and in 9 out of 15 specimens (60%) from the municipalities of Nova Alianca and Botucatu, respectively. The karyotype 2n = 30 + 1B found in D. nanus was similar to that of other species with 2n = 30 chromosomes, except for the presence of an additional small telocentric chromosome. In one specimen from Botucatu, cells with one to three extra chromosomes were observed. These B-chromosomes appeared as univalent in meiosis I and did not bear a nucleolar organizer region or exhibit constitutive heterochromatin.
Highlights
B-Chromosomes are extra chromosomes that occur in animals and plants and are generally considered dispensable for normal development, since they have no apparent function (Jones and Rees, 1982)
We describe the presence of B-chromosomes in specimens of Dendropsophus nanus (= Hyla nana Boulenger, 1889) from two populations collected at different sites in southeastern Brazil
The fluorescence in situ hybridization (FISH) probe consisted of a recombinant HM123 plasmid containing a fragment of Xenopus laevis rDNA (Meunier-Rotival et al, 1979), which was biotin-labelled by nick translation reaction using a BioNickTM Labeling System (Invitrogen)
Summary
B-Chromosomes are extra chromosomes that occur in animals and plants and are generally considered dispensable for normal development, since they have no apparent function (Jones and Rees, 1982). B-chromosomes bear no similarity to the autosomes, are inherited according to a non-Mendelian pattern, and occur as univalents in meiosis (Jones and Rees, 1982; Green, 1991, 2004). The number of B-chromosomes can vary among populations of the same species, among individuals in a population and among cells in an individual. In the latter case, this variation results from anaphase lag, with subsequent elimination of B-chromosomes from some cells or tissues, or, alternatively, it is caused by mitotic non-disjunction, with sister chromatids migrating to the same pole (Clark and Wall, 1996)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
