DNA insertions as a component of the evolution of unique satellite DNA families in two genera of parasitoid wasps: Diadromus and Eupelmus (Hymenoptera)

Abstract

In the two parasitoid wasps, Diadromus collaris and Eupelmus orientalis, the satellite DNAs were each found to consist wholly or largely of a single family (5%-7% of the genome). Several clones of each family were obtained and sequenced. The repeat unit in each species is characterized by both the repetition of a basic motif and the presence of an inserted sequence. Sequence comparisons with satellite DNA from D. pulchellus and E. vuilleti provide plausible scenarios for the evolution of the satellite DNA in each genus. Palindromes and A-rich tracts in each consensus sequence suggest the formation, in vivo, of hairpin structures and bend centers that may play a role in heterochromatin condensation in insects. The insertions in the repeat units of each species also contain these structural features, suggesting that maintenance of these insertions requires constraints similar to those pertaining to the rest of the satellite-DNA unit.