MARINER-LIKE ELEMENTS IN HYMENOPTERAN SPECIES - INSERTION SITE AND DISTRIBUTION

Copies of mariner-like element (MLE) transposons in two species, the b umble bee, Bombus terrestris, and the ant, Myrmica ruginodis, were seq uenced. The full-sized elements are 1250 bp long in both species and i nclude 28-bp inverted terminal repeats. The five copies sequenced were almost-equal-to 75% similar to a mariner element (peach) of Drosophil a mauritiana. The distribution of MLE in 27 hymenopteran species was s tudied by PCR and Southern blot hybridization; 93% of the species cont ained one or more of the four major forms of the element. They are ins erted in their host genomes, in the middle of a degenerated 30 -bp pal indrome, which is itself located in an 85-bp conserved region with a p urine-rich tail at one of its ends. The hymenopteran MLEs lie ih a spe cific insertion site, suggesting that this region is conserved. It is thus possible that this region may be a selectively neutral insertion site, which would explain why these elements are widespread in hymenop teran genomes and are not eliminated by male haploidy.