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 populati ons: North European, Cypriot, Pakistani, Gujarati and Vietnamese. Each STR is situated within an intron; the markers are in the genes for hu man coagulation factor XIII (4bp repeat), lipoprotein lipase (4bp repe at) and CD4 (5bp repeat). Population data were generated for each STR and allele frequencies calculated. A calculation of the level of popul ation substructuring for the three systems was also made. The lipoprot ein lipase STR data showed no evidence for population substructuring, but there was a significant level of substructuring in the other two s ystems. This initial pilot study demonstrates the need to validate eac h marker used for DNA profiling in different human populations, and th at some markers (such as LPL) can be used with confidence in widely di ffering ethnic groups, while others (such as CD4 and F13A) may be of v alue in distinguishing sub-groups.