More sex chromosomes than autosomes in the Amazonian frog Leptodactylus pentadactylus.

摘要: Heteromorphic sex chromosomes are common in eukaryotes and largely ubiquitous birds mammals. The largest number of multiple vertebrates known today is found the monotreme platypus (Ornithorhynchus anatinus, 2n = 52) which exhibits precisely 10 chromosomes. Interestingly, fish, amphibians, reptiles have determination mechanisms that do or not involve morphologically differentiated Relatively few amphibian species carry heteromorphic chromosomes, when present, they frequently represented by only one pair, either XX:XY ZZ:ZW types. Here, contrast, with several evidences, from classical molecular cytogenetic analyses, we 12 a Brazilian population smoky jungle frog, designated as Leptodactylus pentadactylus Laurenti, 1768 (Leptodactylinae), has karyotype 2n = 22 Males exhibited an astonishing stable ring-shaped meiotic chain composed six X Y larger than autosomes found, these data represent ever among vertebrate species. Additionally, sequence variation suggest this may complex species, chromosomal rearrangements possibly played important role evolution process.