Abstract
The ras homologues of Drosophila melanogaster located at 85D and 64B on the polytene chromosome map were cloned using the Ha-ras gene of Harvey murine sarcoma virus as a probe. The genomic sequences of Dmras85D and Dmras64B were determined and shown to differ from previously published sequences. Dmras85D is much more similar to the Ha-ras, Ki-ras, and N-ras genes than it is to either the Dmras64B gene or to the ras genes of Saccharomyces cerevisiae. Comparison of the Dmras85D genomic sequences with the previously published nucleotide sequence (Neuman-Silberberg et al., Cell 37 (1984) 1027-1033) shows that the positions of the two introns are not conserved relative to the positions of the introns in Dmras64B or in vertebrate ras genes. The Dmras64B and Dmras85D transcripts were analyzed by blot hybridization and shown to be dissimilar. The data suggest that the divergence of the Dmras genes was ancient, and that Dmras85D and Dmras64B have different functions.
