Cloning and characterization of a mariner-like element in the silkworm, Bombyx mori

We have identified a mariner-like element (MLE) in the genome of the silkworm, Bombyx mori. The cloned MLE, desiqnated as BmMLE, contained an ORF that was interrupted by insertions, stop codons, and frameshifts. The complete ORF sequence was estimated by sequencing the PCR products. The hypothetical protein coded by this ORF showed 34% homology to the Mos1 element of Drosophila mauritiana, and is phylogenetically very close to MLE of Hyalophora cecropia. BmMLE is present in 80 to 100 copies in the B. mori genome. Many BmMLEs with different lengths were identified by Southern blot analysis and LA PCR of the genomic DNA. The distribution of these BmMLEs differed in geographic races.