A new allele of the short tandem repeat (STR) locus, CSF1PO

CSF1PO is one of the thirteen core loci used for the CODIS database, and al leles reported for this short tandem repeat (STR) locus contain from 6 to 1 5 repeats of the tetranucleotide AGAT. Screening of DNA from 76 individuals by gel electrophoresis and silver stain detection yielded one sample that contained a rare, off-ladder CSF1PO allele; an allele larger than CSF1PO(15 ) was detected in a heterozygote that also contained a CSF1PO(10) allele. C apillary electrophoresis analysis using Gene-Scan (TM) software demonstrate d that the variant allele contained four bases more than CSF1PO(15). Follow ing agarose get electrophoresis to separate the two alleles of the heterozy gote and cycle sequencing using dye terminators, sequence analysis showed t hat the variant, which was otherwise identical to the CSF1PO GenBank sequen ce, contained exactly 16 AGAT repeats. These results demonstrate the existe nce of an additional CSF1PO allele, a previously unreported size variant., CSF1PO(16).