EVOLUTION OF THE COPIA RETROTRANSPOSON IN THE DROSOPHILA-MELANOGASTERSPECIES SUBGROUP

We report the results of a phylogenetic survey of the retrotransposon copia in the melanogaster subgroup of the Drosophila genus. The polyme rase chain reaction was used to amplify the copia 5' long terminal rep eat and the adjacent untranslated leader region from representative me lanogaster subgroup species. Restriction and sequence analyses of this region reveal discrete classes of copia size variants within the mela nogaster subgroup. Phylogenetic comparisons of copia sequence data ind icate that the size variants represent different copia subfamilies whi ch diverged prior to their distribution in the melanogaster subgroup. Our results also suggest that copia elements have been subject to hori zontal and vertical transmission during their evolution.