STR typing of buccal swabs for paternity testing with reference to Japanese population data on the D20S85, D14S118, and D14S543 loci.

To simplify short tandem repeat (STR) typing of genomic DNA, we used buccal cells instead of blood cells. Buccal swabs taken from paternity-test trios were washed with 1 ml of distilled water by centrifugation, and the pellets were suspended in 20 microliters of distilled water. The suspensions were frozen at -80 degrees C and then thawed. Using a 1/5 volume of each suspension, we were able to type STRs at the TH01, D20S85, D14S118, and D14S543 loci by triplex PCR amplification of the first three markers and by simplex amplification of the other. In addition, we studied the polymorphisms at the D20S85, D14S118, and D14S543 loci in a Japanese population of 320 individuals. The four loci have a combined average exclusion power of 99.37%. In 24 cases of disputed paternity, the results of STR typing of the four loci agreed with those of conventional marker typing. In addition to being simple and rapid, STR typing of buccal swabs involves no painful procedure. It is therefore preferable for paternity tests on infants and small children.