These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Chromosome banding in Amphibia. XXII. Atypical y chromosomes in Gastrotheca walkeri and Gastrotheca ovifera (Anura, Hylidae).
    Author: Schmid M, Feichtinger W, Steinlein C, Nanda I, Mais C, Haaf T, Visbal García R, Fernández Badillo A.
    Journal: Cytogenet Genome Res; 2002; 96(1-4):228-38. PubMed ID: 12438804.
    Abstract:
    The chromosomes of the rare South American marsupial frogs Gastrotheca walkeri and G. ovifera were extensively reexamined with various banding techniques. The karyotypes of both species are distinguished by a new category of XY female symbol /XX male symbol female sex chromosomes. The unusual Y chromosomes are characterized by containing the least amount of constitutive heterochromatin in the karyotypes. This is in contrast to all previously known amphibian Y chromosomes and does not fit the evolutionary model of early XY differentiation in vertebrates. In male meiosis, the heteromorphic XY chromosomes of both species still exhibit the same pairing configurations as the autosomes. DNA flow cytometric measurements show the nuclear DNA amount of G. walkeri to be 10.90 pg. The significance of the XY/XX sex chromosomes of these marsupial frogs, the various classes of constitutive heterochromatin detected, and the data obtained from meiotic analyses are discussed in detail.
    [Abstract] [Full Text] [Related] [New Search]