RESUMEN
This paper reports the sequences of two new alleles identified in a population database study on the short tandem repeat D19S253 locus. A Portuguese Caucasian population and a Portuguese African population were studied. Forty-four selected alleles were sequenced and 11 different alleles were found. All the sequenced alleles shown to possess a simple tetranucleotide GATA repeat region structure. The two new alleles, alleles 6 and 16, follow the simple repeat pattern. During paternity investigation casework, 1028 meiosis were analyzed and five isolated genetic incompatibilities detected. In one case, a non-detectable allele with the used set of primers could be the explanation. In the other four cases, single-step mutations could be considered. The mutation rate obtained for this locus was 3.89 x 10(-3).