Genome analysis of Peromyscus (Rodentia, Cricetidae) VII. Localization of satellite DNA sequences and cytoplasmic poly(A) RNA sequences of P. eremicus on metaphase chromosomes.

A satellite DNA fraction from P. eremicus, having a buoyant density of 1.705 g/ml in neutral CsCl density gradients, was isolated. In situ hybridization experiments, using 3H-RNA complementary to this DNA fraction indicated that the short (heterochromatic) arms of most of the autosomes contained this sequence. Conversely, in situ hybridization using 3H-complementary DNA (cDNA) synthesized from the cytoplasmic poly (A) RNA of P. eremicus (comprising a substantial fraction of total messenger RNA) showed that the number of silver grains in the long arms (euchromatin) was significantly higher than that in the short arms. The X chromosomes showed a distinct localization pattern of both sequences.