Banded krait minor satellite (Bkm) contains sex and species-specific repetitive DNA.

A novel class of repetitive DNA was isolated from a Bkm DNA library by exclusion hybridization. This sequence was mapped to the short arm of the W chromosome of banded krait, Bungarus fasciatus. Southern blot hybridization showed that these sequences are sex and species specific. Sequence analysis of a 206 bp long clone, BR87, revealed the presence of a tandem array of two internal repeat units of 18-19 bp alternating with each other with a gap of 1, 2 of 3 nucleotides. To our knowledge, this is the first report of an exclusively W chromosome- and species-specific repeat isolated from any reptile. The functional significance of this sequence based on its organisation is discussed.