Inactivated mariner-like elements (MLE) in pink bollworm, Pectinophora gossypiella.

We isolated multiple copies of mariner-like element (MLE) from the pink bollworm (PBW), Pectinophora gossypiella, a key lepidopteran cotton pest. Although all the MLE sequences contain multiple mutations accumulated in their transposase coding region, the consensus sequence revealed a putative ancestral transposase encoding 339 amino acid residues with a D,D(34)D motif, and 36 bp inverted terminal repeats, belonging to the cecropia subfamily, and most similar to the MLE found in Antheraea species. Examining six different pink bollworm populations, we conclude that the MLE in PBW described in this study are ancient and are undergoing the process of accumulating inactivating mutations. This conclusion is supported by the patterns of polymorphisms revealed by genomic Southern hybridization, transposable element displays, and sequences from multiple MLE.