[A new class of mobile genetic elements of Drosophila melanogaster]

Clone Dm A89 was obtained upon cloning of DNA fragments coding abundant poly(A+)RNA's of D. melanogaster. Dm A89 was identified as a new transposable element using in situ hybridization with polytene chromosomes of two independent highly isogenic lines of D. melanogaster oregon RC and gt wa Dm A89 hybridizes with approximately 20 sites in each line. A portion of Dm A89 is homologous to the distal part of type I ribosomal gene insertion sequence and is highly repetitive. Two other sections of the clone have much less redundancy. The unity of the three fragments is not casual, as revealed by cloning of some other genomic sequences homologous to Dm A89. Dm A89 is actively transcribed throughout the development of D. melanogaster and produces polyadenylated RNA 1.1 kb long.