The distribution of HLA DQA1 and D1S80 (pMCT118) alleles and genotypes in the populations of Galicia and central Portugal

HLA-DQA1 in autochthonous Basques: description of a genocline for the DQA1*0201 allele in Europe

A total of 250 autochthonous Basque individuals were tested in the HLA-DQA1 system, and the allele frequency distribution found was significantly different from that of any other European population. The differences centre mainly on the alleles DQA1*0201 and DQA1*0501: for the former the Basques have the highest frequency described anywhere in the world (f = 0.210) and for the latter they have the lowest frequency in Europe (f = 0.204). For the allele DQA1*0201 a genocline is also described in Europe with the Basques and Finno-Ugric populations basically at the extremes. The genocline reflects the isolation of the Basque population since prehistoric times, and supports existing linguistic, archaeological and genetic data.

Effect of environmental factors on PCR-DNA analysis from dental pulp

This study was designed to observe the results of DNA typing on teeth subjected to aging, different temperatures and various environmental factors. A total of 570 teeth were studied. The study included the analysis of the PCR-based polymorphisms HLA DQA1, D1S80, HUMTH01, HUMFES/FPS and the XY homologous gene amelogenin. In general the best results were obtained with the XY homologous gene amelogenin, followed by the two STRs studied (HUMTH01 and HUMFES/FPS). The small fragment sizes and the method of detection used after PCR amplification are the main factors explaining this fact. In general, teeth submerged in water gave the poorest results. Teeth exposed to outdoor conditions provided better results than teeth buried in sand or soil, but even in these cases good results were obtained. Up to 4 degree C, temperature had only a slight influence on the results. Positive results were obtained in most cases at high temperatures (400 degrees C for 2 min) which are rarely reached in practical casework. Positive typing results for the XY homologous gene amelogenin and the STRs were obtained from teeth 10-30 years old. The usefulness of dental pulp for identification purposes is exemplified in some actual cases.

Distribution of HLA DQ A1 alleles and genotypes in two Spanish populations (Aragon and Asturias)

HLA DQ A1 is probably one of the PCR-based genetic marker systems most widely used in actual forensic casework analyses. As accurate data about the distribution of the alleles is one of the most important prerequisites for the application in forensic biology, we studied the allele distribution in two relevant Spanish populations (Aragonese and Asturian). Results were in good agreement with the Hardy-Weinberg law in both Aragonese and Asturian populations. The power of discrimination was 0.92 in the Aragonese and 0.93 in Asturian sample. A test for homogeneity of the HLA DQ A1 population data based on alelle frequency counts for 12 European samples was performed and no significant differences were found (P = 0.831).

Study of three AMPFLPs (D1S80, 3'ApoB and YNZ22) in the population of the north of Portugal

Allele and genotype frequencies for D1S80, 3'ApoB and YNZ22 loci have been determined in a population sample of the North of Portugal using the polymerase chain reaction (PCR) amplification and nonradioactive detection. The distribution of genotypes in the three polymorphisms studied is in agreement with expected values according to the Hardy-Weinberg equilibrium. The combined chance of exclusion for the three systems is 0.96, and the combined power of discrimination is 0.99.

Analysis of the D1S80 (pMCT118) VNTR locus polymorphism in a native Kuwaiti population by the polymerase chain reaction

We have determined the allele and genotype frequencies at the hypervariable locus D1S80 in a native Kuwaiti population using the polymerase chain reaction technique and subsequent high resolution gel electrophoresis. In a sample of 200 individuals, 21 alleles and 57 genotypes were detected. The alleles with 18 and 24 repeat units were most common with frequencies of 0.188 and 0.408 respectively. The distribution of the observed genotypes was in agreement with the Hardy-Weinberg equilibrium prediction. The observed heterozygosity for the population sample was 0.80 with the allelic diversity of 0.781 +/- 0.029 and the power of discrimination was 0.94. The data obtained in this study are potentially useful for individual identification in forensic casework.

The use of the STRs HUMTH01, HUMVWA31/A, HUMF13A1, HUMFES/FPS, HUMLPL in forensic application: validation studies and population data for Galicia (NW Spain)

The 5 tetranucleotide short tandem repeats, HUMTH01, HUMVWA31/A, HUMF13A1, HUMFES/FPS and HUMLPL were studied using different electrophoretic methods and PCR amplification conditions in order to optimize the typing conditions. A genetic population study in the population of Galicia was carried out and the allele and genotype frequencies are given. Compliance with the Hardy-Weinberg equilibrium was tested using different statistical parameters, with clear advantages resulting in favor of using the exact test (Guo-Thompson method) instead of conventional chi-square methods. Some statistical parameters of forensic interest (PD, CE, h) were also calculated. There were no mutations found in a total of 73 paternal meioses and 101 maternal meioses. Abnormal electrophoretic mobility was found in the AT-rich STR HUMF13A1 under non-denaturing conditions and, therefore, the use of denaturing conditions is absolutely necessary. No "stutter" bands were found, although double peaks in the HUMFES/FPS system were observed in some samples. The advantage of using automated sequencers with fluorescent technology is also reported.

Genetic markers: association study in migraine

Eleven genetic markers were typed in 112 unrelated patients with migraine (50 with aura, 62 without aura) and compared with a random sample of healthy individuals. No significant differences were found for the ABO and Rh systems, acid phosphatase 1, phosphoglucomutase 1, adenosine deaminase, haptoglobin, transferrin, alpha-1-antitrypsin, and D1S80. Strong associations between the group of patients with migraine and group-specific component GC 1F-1F and esterase-D ESD 2-2 phenotypes were observed. These associations raise the possibility that a molecular genetic factor for migraine may exist in or near the Group Component (chromosome 4) and Esterase D (chromosome 13) loci, and represent a first comprehensive step in the eventual localization and isolation of the migraine genes.

Allele frequency distribution of four PCR-amplified loci in the Spanish population

The allele frequency distributions of four VNTR loci amplified by PCR have been studied in a population of 205 individuals from Spain. The loci analysed are D1S80 and three STRs: HUMTH01, HUMFES/FPS and HUMACTBF2 (SE33). The former was visualized in Metaphor agarose gels, and the STRs in sequencing polyacrylamide gels under denaturing conditions which could separate alleles with differences of a single base. This is of particular importance in the HUMTH01 locus, a tetrameric STR in which two alleles (9.3 and 10) were detected differing in a single base. Furthermore, HUMACTBP2 has at least 30 alleles, some of which may vary by as little as one base. At this locus a variation in the allele mobility was observed, depending on the electrophoretic conditions. For this reason, there should be careful consideration before this marker is accepted and validated as a common interlaboratory system. This paper does not include any comparison of the frequencies obtained for this locus with other recent studies. For the rest of the loci, the frequencies found have been compared with other published population studies; they show a degree of difference, particularly in the D1S80 locus. Finally, the systems were tested for Hardy-Weinberg equilibrium, and some statistical parameters of forensic interest were calculated.

Distribution of HLA DQA.1 alleles in New Zealand Caucasian, Maori and Pacific Islander populations. Comparison with other population studies

Allele and genotype frequencies for the HLA DQA.1 locus were determined for 127 unrelated Caucasians, 177 unrelated Maori and 98 unrelated Pacific Islanders from the New Zealand population. DNA from blood cells was analysed by polymerase chain reaction amplification of DNA followed by hybridization to allele specific oligonucleotide probes in a reverse dot-blot test. Allele frequencies at the HLA DQA.1 locus for New Zealand Caucasians, Maori and Pacific Islanders were compared with published data for other populations. The distribution of HLA DQA.1 genotype frequencies did not deviate from Hardy Weinberg expectations for the Caucasian and Maori populations. The power of discrimination was 0.93 for Caucasians and 0.86 for Maori. The total Pacific Islander population tested was analysed as was data obtained from Western Polynesians contained within that larger group. Both the total Pacific Islander group analysed, and the Western Polynesians contained within that larger group, failed Hardy Weinberg expectations for the distribution of HLA DQA.1 genotypes. This significant deviation was due to excess homozygotes. The power of discrimination for the total Pacific Islander group and for Western Polynesians was 0.86 and 0.85 respectively. Comparison of Caucasian population studies from New Zealand, the United Kingdom, South Australia, Norway, the United States and Sweden showed these populations have similar HLA DQA.1 allele frequency distributions. Maori and Pacific Islanders have HLA DQA.1 allele frequency distributions that are more similar to each other than any of the other populations studied.