Heterozygosity and allele frequencies of the two VNTRs (ApoB and D1S80) in Iranian population.

Genetic markers are used for identity testing and paternity analysis depends on knowing the allele frequencies in the population. Minisatellites show allelic variability in the number of repeat units. We have studied the allele frequencies and heterozygosity of two VNTRs (ApoB and D1S80) in Iranian populations. A total of 96 and 82 chromosomes were analyzed by PCR and gel electrophoresis for ApoB and D1S80 respectively. In the ApoB system, allele 37 was the most common followed by allele 35 whereas allele 23 was the most common followed by allele18 at the D1S80 locus. Observed heterozygosity was relatively low in ApoB than D1S80 locus, however, no significant differences were found between observed and expected heterozygosity.

Prenatal Determination of Fetal Rh, Kell and MN Blood Group Antigens by DNA Analysis of Amniotic Fluid / 대한임상병리학회지

BACKGROUND: Prenatal determination of a blood antigen of a fetus at risk for hemolytic disease of the newborn makes the obstetrician facilitate to take timely procedures such as intra-uterine transfusion or plasma exchange. However, determining the phenotype of a fetal antigen is of limited use because fetal RBCs must be obtained by periumbilical blood sampling which entails considerably greater adverse outcomes than an amniocentesis does. METHODS: Genotypes of Rh, MN and Kell systems using 14 amniotic fluid samples were compared with phenotypes of cord blood. The incidence of maternal blood contamination in 8 amniotic fluid samples which were obtained during mid-trimester was estimated by amplification of variable number of tandem repeat(VNTR) D1S80. The detection sensitivity of each technique was evaluated by artificially mixed samples. RESULTS: All the 14 paired samples of amniotic fluid and cord blood showed identical results between the genotype of amniocyte and the phenotype of cord blood. Of 8 paired samples of amniotic fluid and maternal blood, D1S80 VNTRs of fetuses were evidently amplified and there were no evidence of maternal blood contamination. The detection sensitivity of Rh(E) and Rh(c) genotyping was 0.5% by ethidium bromide staining, while D1S80 VNTR was 10%. Heterozygosity of D1S80 VNTR was 94%. CONCLUSIONS: Genotypes of Rh, MN and Kell systems could be prenatally determined by this technique. Since the heterozygosity of D1S80 VNTR is high up to 94% in Koreans, D1S80 VNTR could be effectively used in determining the maternal blood contamination of amniotic fluid. The prenatal determination of fetal red cell antigen genotypes by this technique will be helpful for the management of sensitized pregnancies at risk for HDN.

PATERNITY TESTING BY ANALYSIS OF THREE VNTR GENETIC MARKERS / 中国法医学杂志

The polymorphisms of VNTR loci D1S80 (pMCT 118), D17S30 (pYNZ-22 ) and ApoB3' in blood and tissues were detected by amplified fragment length polymorphism (Amp-FLP) technique,and was applied in the paternity testing cases. The discriminating power (DP) of D1S80,D17S30 and ApoB3'were 0. 962, 0. 956 and 0. 960 respectively. The cumulative probability of paternity exclusion (EPP) of the three VNTR loci was 94. 51 %,higher than that of conventional blood typings.