CARIÓTIPOS E REGIÕES ORGANIZADORAS DE NUCLÉOLOS (RON) DE Marmosa E Didelphis (DIDELPHIDAE) DO ESTADO DE TOCANTINS, BRASIL.

Abstract

Karyotypes and nucleolar organizer regions of Marmosa and Didelphis (Marsupialia, Didelphidae) fron the state of Tocantins, Brazil.Karyotypes of two marsupialis from the state of Tocantins were studied: one female Marmosa murina and Didelphis marsupialis. In M. murina, 2n=14 and AN=22, the 3 first pairs of autosomal chromosomes are submetacentric, the forth pair is metacentric, the fifth pair is subtelocentric, and the sixth pair is acrocentric. The X chromosome is acrocentric and heteromorphic. Nuclear regions (NORs) were present in the pericentric region of pair number 5 and in the telomeric region of pair 6. In D. marsupialis, 2n=22 and AN=20, the smaller acrocentric chromosomes had four NORs while the lager pairs of crocentric chromosomes had fve or six.