Odd diploid number in both sexes and a unique multiple sex-chromosome system of a rodent, Vandeleuria o. Oleracea (Bennett)

Abstract

Vandeleuria o. oleracea, a rodent, has an odd diploid number of chromosomes (2n=29) in somatic and germ cells of males as well as in somatic cells of females. The odd element, which is constantly present in both sexes, is a member of a sex-chromosome complex, for it forms a characteristic sex heterotrivalent during male meiosis. In both somatic and germ cells of the male, an X₁X₂Y multiple sex-chromosome complex is present. In the female, only somatic cells have been studied, and in these an X₁X₁X₂ complex is found. The relative length of the presumptive X₁ is 3.3±0.06% and of the X₂, 2.1±0.08% of the haploid complement.