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 development of DNA profiling database in an HAE III based RFLP system for Chinese, Malays, and Indians in Singapore.

Deoxyribonucleic acid (DNA) restriction fragment length polymorphism (RFLP) profiles were obtained for blood specimens from the three population groups--Chinese, Malays and Indians--in Singapore. The population databases were collected from Hae III digested high molecular weight DNA hybridized with four variable number of tandem repeats (VNTR) loci--D2S44, D10S28, D4S139 and D1S7. The data were analyzed statistically using the fixed bin system. Comparison of ratio of bin frequencies of these population data with published data on whites, blacks, and hispanics shows that the alleleic distribution at these loci is not seriously different among the six groups. This has important implications to the statistical significance of forensic DNA applications.

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.

Pulmonary atelectasis from compression of the left main bronchus by an aortic aneurysm.

Pulmonary atelectasis may be caused by endobronchial lesions or by extrinsic compression of the bronchus. However, lung collapse due to compression from a thoracic aneurysm is uncommon. We report a 76-year-old hypertensive female patient who has pulmonary atelectasis due to an extrinsic compression from a descending thoracic aortic aneurysm, and discuss possible treatment options.

Population genetic characteristics of the STR Loci D21S11 and FGA in eight diverse human populations.

A highly polymorphic multiplex short tandem repeat (STR) system composed of D21S11, FGA, and the sex-typing system amelogenin (AMG) has been used to investigate allele frequency distributions in two Canadian Caucasian samples (British Columbia and Alberta), three Canadian aboriginal populations (Coastal Salishans from British Columbia, Ojibwa from northern Ontario, and Cree from Saskatchewan), and three ethnic groups from Singapore (Chinese, Malays, and Asian Indians). Using the automated fluorescence detection approach on an ABD 373A DNA Sequencer, we distinguished 20 D21S11 and 22 FGA alleles with a nearly equal representation of two- and four-base variants. An overlap in allele sizes for both STR loci across populations was observed, but frequency differences were noted. Statistical analysis revealed that (1) both D21S11 and FGA loci conform to Hardy-Weinberg equilibrium in all eight surveyed populations based on five different tests and (2) both STR loci are in linkage equilibrium. Results from the 2 x N contingency table exact tests for population differentiation demonstrated that the Canadian samples from two different provinces were not distinguishable from one another at either STR locus and therefore could be combined to form one Caucasian group. Likewise, Chinese and Malays from Singapore did not show significant differences at either STR locus. In contrast, all other examined populations exhibited differences deemed statistically significant. As a complement to our study, we compared D21S11 allele frequency distributions in 21 worldwide populations and FGA allele frequency distributions in 14 populations. Many alleles never previously reported in worldwide populations were identified in Canadian aboriginal and Asian samples from this study. Twenty-four D21S11 and 29 FGA alleles were distinguished in worldwide groups. Interesting similarities in allele frequency distribution patterns across populations suggest that the STR polymorphism at these loci predates the geographic dispersal of ancestral human populations. This study further demonstrates the utility of highly informative STR loci such as D21S11 and FGA in human population evolutionary history and in forensic medicine.