INTERPRETATION OF SEX CHROMOSOMAL RNA SYNTHESIS IN THE OPOSSUM, DIDELPHIS VIRGIMANA

Abstract

RNA synthetic activity is detectable in both sex chromosomes of cultured lymphocytes from male and female opossums (Didelphis virginiana). The possibility that this synthesis may represent genetic activity in the sex chromosomes is discussed. A hypothesis is presented which suggests translocation of autosomal material to sex chromosomes in the evolution of D. virginiana from D. marsupialis. This hypothesis might also explain some or all of the many other unusual cytogenetic characteristics of D. virginiana.