IDENTIFICATION OF NEW MEDIUM REITERATION FREQUENCY REPEATS IN THE GENOMES OF PRIMATES, RODENTIA AND LAGOMORPHA

We report eleven new families of MEdium Reiteration frequency (MER) in terspersed repeats in the genomes of Primates, Rodentia, and Lagomorph a. Two families of the human repeats, MER46 and MER47, represent non-a utonomous DNA transposons. These sequences are flanked by TA target si te duplications and have terminal inverted repeats (TIRs) similar to T IRs of DNA. transposons. The sequences of five other families of repea ts, MER41, MER48, MER50, MER51, and RMER3, resemble long terminal repe ats of retroviruses. A potential involvement of some of the reported M ER repeats in the regulation of transcription and genetic rearrangemen ts is suggested. Age estimations place the origin of most MER repeats at the time of decline in MIR (Mammalian-wide Interspersed Repeats) re troposition and before the origin of the Alu family.