Sex Chromatin in Somatic Cells of the Philander opossum quica(TEMMINCK, 1827, Marsupialia)

Abstract
In both sexes the Brazilian marsupial Philander opossum quica (Temminck, 1827) presents one conspicuous chromocenter in its somatic cells at interphase. The sex chromatin body in males is about half the size of the sex chromatin in females. A small, positively heteropycnotic chromosome is seen at prophase, prometaphase and metaphase in both sexes; in males it is half the size of the heteropycnotic chromosome seen in females. The sex chromosomes in this animal are the smallest in the karyotype and the Y chromosome is half the size of the X chromosome. It is concluded that in this species the sex chromatin body is formed by one condensed X chromosome in females and by the condensed Y chromosome in males.