Sequence analysis and allelic designation of the two short tandem repeat loci D18S51 and D8S1179

This paper reports the sequences of eleven D8S1179 and twenty one D18S51 alleles. The D8S1179 alleles ranged in size from 162 bp to 202 bp and increased in size by regular 4 bp increments. They were shown to possess a compound repeat region composed of the tetranucleotides TCTA and TCTG. Alleles at the D18S51 locus ranged in size from 271 bp to 343 bp and possessed a simple repeat region composed of the tetranucleotide AGAA. The majority of alleles increased in size by 4 bp increments corresponding to the addition of one tetranucleotide repeat unit. However, three alleles differed in size by 2 bp from the 4 bp increment as a result of a dinucleotide insertion within the 3' flanking region. These alleles also exhibited an altered 3' flanking sequence in the first four nucleotides following the repeat region. The allelic designations proposed for these loci on the basis of this sequence data are currently being used in a multiplex PCR profiling system employed in a National DNA database in the United Kingdom.