Different ancestor alleles: a reason for the bimodal fragment size distribution in the minisatellite D2S44 (YNH24)

Three conserved repeat order motifs found in the D2S44 (YNH24) minisatellite by minisatellite variant repeat mapping by PCR (MVR-PCR) might be the remnants of three different ancestor alleles. One of the motifs is found in the group of alleles around the 2.8 kbp fragment size and the two others in the group of alleles around the 4.1 kbp fragment size in the bimodal frequency distribution of HinfI fragments characteristic for the D2S44 minisatellite. The conserved repeat-order motifs were found at the 3'-end of the alleles, whilst the 5'-end was highly polymorphic. This is the first time a minisatellite is shown to have repeat-order motifs that are associated with fragment length. These results were obtained by MVR-PCR mapping of 49 alleles with primers specific for the core nucleotide sequence variation ...(G)5TGTT, ...(G)4TTGTT or ...(G)4TGTT.