Variation of short tandem repeats within and between populations.

Using the polymerase chain reaction (PCR) the frequency distributions of three short tandem repeats (STR) were investigated in five populations: North European, Cypriot, Pakistani, Gujarati and Vietnamese. Each STR is situated within an intron; the markers are in the genes for human coagulation factor XIII (4bp repeat), lipoprotein lipase (4bp repeat) and CD4 (5bp repeat). Population data were generated for each STR and allele frequencies calculated. A calculation of the level of population substructuring for the three systems was also made. The lipoprotein lipase STR data showed no evidence for population substructuring, but there was a significant level of substructuring in the other two systems. This initial pilot study demonstrates the need to validate each marker used for DNA profiling in different human populations, and that some markers (such as LPL) can be used with confidence in widely differing ethnic groups, while others (such as CD4 and F13A) may be of value in distinguishing sub-groups.