Messenger RNA complexity in Drosophila melanogaster.

Complementary DNA was synthesized as a copy of polyadenylated RNA from the cytoplasm of Drosophila cultured cells. The kinetics of hybridization of cDNA with the RNA used as template revealed a complex distribution of frequencies in the population of polyadenylated RNA. Computer simulation suggested three frequency classes containing about 4, 190, and 6700 different RNA molecules of mean molecular weight 4 x 10-5. About 15% of this complementary DNA reacted with repetitive sequences of Drosophila DNA. The most frequent polyadenylated RNA is preferentially enriched in its content of repetitive sequences. Comparative experiments using cDNA synthesized as a complement of larval polyadenylated RNA demonstrated some stage specific changes in the population of polyadenylated RNA.