Possible horizontal transfer of mariner-like sequences into some invertebrates including lepidopteran insects, a grasshopper and a coral

Abstract

Marine-like elements (MLEs) were amplified by PCR against genomic DNAs from several Japanese lepidopteran species, using the inverted terminal repeats (IR) of the Hyalophora cecropia MLE as a primer. Clones thus obtained were of a size of about 1.3 kb, and expected to contain the full-length MLE. A 1.3-kb band was also amplified against genomic DNA from the grasshopper, Traulia ornata, and from a coral allocated to the Fungia family. All of the 1.3-kb bands were cloned and analyzed for nucleotide sequence. Multi-alignment analyses of the results indicated that the clones were highly similar to each other and classified into the cecropia subfamily of MLEs. The coral MLE was found to have a complete ORF coding for transposase, a situation similar to that previously found in the Emperor moth, Attacus atlas, from the Ryukyu island. These findings, together with the fact that all of the insects and coral species that exhibited a positive signal for the full-length MLE were collected in relatively close regions around Japan, indicated that the horizontal transfer of MLEs had taken place even among phylogenetically remote organisms.