Hypervariable Bkm DNA Loci in a Moth, Ephestia kuehniella : Does Transposition Cause Restriction Fragment Length Polymorphism?

Bkm sequences, originally isolated from snake satellite DNA, are a component of eukaryote genomes with a preferential location on sex chromosomes. In the Ephestia genome, owing to the presence of only a few Bkm-positive BamHI restriction fragments and to extensive restriction fragment length polymorphisms between and within inbred strains, a genetic crossbreeding analysis was feasible. No sex linkage of Bkm was detected. Instead-depending on the strain-two or three autosomal Bkm DNA loci were identified. All three loci were located on different chromosomes. Fragment length and transmission of fragments was stable in some crosses. In others, changes in fragment length or loss of the Bkm component were observed, probably depending on the source strain of the fragment. The anomalous genetic behaviour is best accounted for by the assumption that Bkm sequences are included in mobile genetic elements.