Analysis of the D1S80 locus by amplified fragment length polymorphism technique in the Chinese, Malays and Indians in Singapore.

The distributions of the D1S80 alleles and genotypes in the Chinese, Malays and Indians in Singapore were determined by amplified fragment length polymorphism (AMP-FLP) analysis. The distributions of the observed genotypes for the three races conformed to Hardy-Weinberg expectations. The system was applied to 19 families whose paternity had been established by restriction fragment length polymorphism (RFLP) analysis. In all cases, Mendelian inheritance of the alleles at the D1S80 locus could be demonstrated. D1S80 typing on DNA recovered by differential extraction of forensic specimens which included vaginal swabs, urethral swabs and seminal stains yielded consistent results.

The application of restriction fragment length polymorphism to disputed paternity.

The Hae III restriction fragment length polymorphism (RFLP) system with four variable number tandem repeats (VNTR) loci has been used to resolve disputed paternity. The system exhibits an average power of exclusion of 99.96% and a mean probability of paternity of 99.96%. In all the casework examined, three VNTR loci provided a minimum 98.11% of probability of paternity. With four VNTR loci, the minimum probability of paternity was 99.69%. The alleged fathers in these cases were of different races: Chinese, Malay, Indian, Caucasian and Black, suggesting that the RFLP system is not biased for any race. This RFLP system has also been used to resolve disputed paternity cases involving related alleged fathers and cases of "motherless children". To date, we have not observed any mutation or recombination on either the maternal or paternal alleles. These results suggest that the RFLP system with four VNTR loci can decisively resolve the biological relationship in disputed paternity cases.