Mitochondrial DNA sequence analysis of a native Bolivian population.

Mitochondrial DNA analysis is very useful for the interpretation of the history of human migration and to estimate the frequency of a haplotype in the forensic context. From a human settlement perspective, La Paz area is greatly interesting since the first planned city of the region is located there. Samples from 110 individuals from La Paz were studied analysing the polymorphisms in the D-loop, hypervariable region I (HVI) and hypervariable region II (HVII) in order to verify the genetic diversity. The aim of this study was to start the creation of a population database in order to obtain the genetic interpopulation variability and classify haplotypes into characteristic haplogroups of South America. A total of 97 different haplotypes were identified, 90 being unique, expressed by 122 polymorphic nucleotide positions. Nucleotide and sequence diversity were estimated to be 0.015 +/- 0.0075 and 0.996, respectively. Haplogroup distribution in the samples was 57.27% B4, 19.09% C1, 10.00% A2, 3.64% D1, 2.73% D4h3, 1.82% H, and 0.91% for each of the haplogroups A4, B4c1a, CZ, D4J, M7a and M8/N9b. The rate of length heteroplasmy was 36.36% in HVI and 52.73% in HVII. Phylogenetic analysis reveals proximity to the Korean, Chilean aboriginal, Japanese and Australian populations. The estimated genetic variability of the studied population was high, suggesting an early settlement.

Analysis of body fluid mixtures by mtDNA sequencing: An inter-laboratory study of the GEP-ISFG working group.

The mitochondrial DNA (mtDNA) working group of the GEP-ISFG (Spanish and Portuguese Group of the International Society for Forensic Genetics) carried out an inter-laboratory exercise consisting of the analysis of mtDNA sequencing patterns in mixed stains (saliva/semen and blood/semen). Mixtures were prepared with saliva or blood from a female donor and three different semen dilutions (pure, 1:10 and 1:20) in order to simulate forensic casework. All labs extracted the DNA by preferential lysis and amplified and sequenced the first mtDNA hypervariable region (HVS-I). Autosomal and Y-STR markers were also analysed in order to compare nuclear and mitochondrial results from the same DNA extracts. A mixed stain prepared using semen from a vasectomized individual was also analysed. The results were reasonably consistent among labs for the first fractions but not for the second ones, for which some laboratories reported contamination problems. In the first fractions, both the female and male haplotypes were generally detected in those samples prepared with undiluted semen. In contrast, most of the mixtures prepared with diluted semen only yielded the female haplotype, suggesting that the mtDNA copy number per cell is smaller in semen than in saliva or blood. Although the detection level of the male component decreased in accordance with the degree of semen dilution, it was found that the loss of signal was not consistently uniform throughout each electropherogram. Moreover, differences between mixtures prepared from different donors and different body fluids were also observed. We conclude that the particular characteristics of each mixed stain can deeply influence the interpretation of the mtDNA evidence in forensic mixtures (leading in some cases to false exclusions). In this sense, the implementation of preliminary tests with the aim of identifying the fluids involved in the mixture is an essential tool. In addition, in order to prevent incorrect conclusions in the interpretation of electropherograms we strongly recommend: (i) the use of additional sequencing primers to confirm the sequencing results and (ii) interpreting the results to the light of the phylogenetic perspective.

Mutation rates at Y chromosome specific microsatellites.

A collaborative work was carried out by the Spanish and Portuguese ISFG Working Group (GEP-ISFG) to estimate Y-STR mutation rates. Seventeen Y chromosome STR loci (DYS19, DYS385, DYS389I and II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS460, DYS461, DYS635 [GATA C4], GATA H4, and GATA A10) were analyzed in a sample of 3,026 father/son pairs. Among 27,029 allele transfers, 54 mutations were observed, with an overall mutation rate across the 17 loci of 1.998 x 10(-3) (95% CI, 1.501 x 10(-3) to 2.606 x 10(-3)). With just one exception, all of the mutations were single-step, and they were observed only once per gametogenesis. Repeat gains were more frequent than losses, longer alleles were found to be more mutable, and the mutation rate seemed to increase with the father's age. Hum Mutat 26(6), 520-528, 2005. (c) 2005 Wiley-Liss, Inc.

Individual genetic identification of biological samples: a case of an aircraft accident.

In 2003, an aircraft accident occurred in the Madeira island north coast, in which 10 persons (4 female and 6 male) have died. STRs (autosomic and Y-chromosome) and mtDNA were made in order to identify the recovered human body remains and results compared with relatives.

A study on ten short tandem repeat systems: African immigrant and Spanish population data.

This work presents the results obtained from a genetic-population study for the D1S1656 system in the population of Southwest Spain (Huelva, Cádiz and Sevilla), Spaniards of Caucasian origin from North Africa (Ceuta), as well as in the black Central West African and Moroccan immigrant populations in Spain. The results of a study of the autochtonous population of the Canary Islands (n=138), and immigrant Central West African populations in Spain (n=132), obtained for nine short tandem repeat (STR) loci (D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820), as well as the amelogenin locus, all contained in Profiler Plus (Perkin-Elmer) PCR amplification kits, are also presented. Except for the FGA and VWA data on immigrant Central West African populations in Spain, no deviations from the Hardy-Weinberg equilibrium were detected.

Population genetics of nine STR loci in two populations from Brazil.

The Short Tandem Repeats (STRs) D3S1358, HUMvWA31/A, HUMFIBRA/FGA, D8S 1179, D2S11, D18S51, D5S818, D13S317, and D7S820 were studied in two Brazilian populations (from Amazonia and S. Paulo) using the "AmpF1 STR Profiler Plus PCR Amplification Kit." The nine loci showed a combined discrimination power greater than 0.9999999999 and a chance of exclusion of 0.9999.

Population study of HUMTH01, HUMVWA31/A, HUMF13A1, and HUMFES/FPS systems in Azores.

The tetrameric short tandem repeat polymorphisms HUMTH01, HUMVWA31/A, HUMF13A1, and HUMFES/FPS were studied in blood stains obtained from a population of unrelated individuals from the Azores Archipelago (Portugal). Gene frequencies were determined and no deviation from the Hardy-Weinberg equilibrium was found. However, the allelic independence test between loci showed linkage disequilibrium between HUMVWA31/A and HUMFES/FPS. A combined discrimination power and chance of exclusion of, respectively, 0.9999 and 0.9534, reveal the high forensic interest of the four systems. No differences with other caucasoid populations were found, but comparison with some asiatic, eskimo, and amerindian populations showed significant statistical differences.

Results of collaborative study regarding the standardization of the Y-linked STR system DYS385 by the European DNA Profiling (EDNAP) group.

Y-chromosome linked short tandem repeat (STR) loci are inherited as a closely linked haplotype, which appears to remain stable in a given paternal lineage over many generations. In forensic cases, Y-linked STRs are particularly useful for the identification of human remains as well as in rape cases with mixed male/female stain samples. DYS385 is derived from tandemly duplicated segments of the Y chromosome thus giving rise to two fragments of variable length which do not behave like alleles but genotypes. The European DNA Profiling (EDNAP) group has carried out a collaborative exercise among 14 participating laboratories using DYS385 for typing of five unknown bloodstains and a control sample. Furthermore, population data from eight different European countries with samples sizes between 91 and 150 male individuals were collected. The results confirm previous observations that DYS385 is one of the most informative Y-linked STR loci. It could also be demonstrated that reproducible results can be obtained independently from the electrophoretic separation and detection methods used. Thus DYS385 may serve as a useful complementation to the routinely used autosomal STR systems in special cases.

Allele distribution of three STRs in a population from Mozambique.

The short tandem repeat systems (STRs) D12S391, HUMFIBRA/FGA and HUMACTBP2 (SE33) were studied in a population of unrelated individuals from the Maputo area of south Mozambique.

Population distribution of six PCR-amplified loci in Madeira Archipelago (Portugal).

Frequency data of the short tandem repeat (STR) loci HUMTH01, HUMVWA31/A, HUMF13A1, HUMFES/FPS, D12S391 and HUMFIBRA/FGA were determined in blood stains obtained from a population of unrelated individuals from the Madeira Archipelago. The observed genotype distribution showed no significant deviation from the Hardy-Weinberg equilibrium and there was no evidence for association of alleles among the six loci. Population data showed a combined discrimination power of 0.9999998 and a chance of exclusion of 0.99597. The frequencies are similar to those of other compared caucasian populations but significant differences were found between the Madeira population and Japanese, Chinese, Greenland Eskimos and Quechua Amerindians. The six loci studied, together proved to be highly discriminating and valuable for forensic cases.

Report of the European DNA Profiling Group (EDNAP)--an investigation of the hypervariable STR loci ACTBP2, APOAI1 and D11S554 and the compound loci D12S391 and D1S1656.

This paper describes the results of three collaborative exercises which continues the EDNAP theme to explore whether uniformity of DNA profiling results could be achieved between European laboratories using STRs. In an earlier exercise, complex hypervariable AAAG-repeat STR loci were investigated, but reproducibility was found to be poor because of the variation of techniques used by participating laboratories. In the exercise reported here, an internal allelic ladder composed of ACTBP2 and D11S554 fragments was distributed. This ladder was used to size ACTBP2 analysed by a "singleplex" PCR amplification and D11S554 combined with APOAI1 in a separate "duplex" reaction. Laboratories were asked to test 7 blood stains, one of which was a known control, and to report the results to the co-ordinating laboratory. The exercise demonstrated that ACTBP2 showed good reproducibility between laboratories, whereas further testing would be needed to validate APOAI1 and D11S554 for interlaboratory comparisons. In separate exercises, the simple loci D12S391 and D1S1656 were tested; both of these showed excellent reproducibility between laboratories.

Report of the European DNA profiling group (EDNAP): an investigation of the complex STR loci D21S11 and HUMFIBRA (FGA).

This paper describes a collaborative exercise which was intended to demonstrate whether uniformity of DNA profiling results could be achieved between European laboratories using two complex short tandem repeat (STR) loci. The loci D21S11 and HUMFIBRA (FGA) were chosen because they are commonly used by different European laboratories. D21S11 has approximately 14 common alleles (f > 0.001), whereas HUMFIBRA has 19 common alleles. Laboratories were asked to test seven blood stains, one of which was a known control, and to report the results to the coordinating laboratory. The exercise demonstrated that complex STRs were amenable to standardisation.

A review of the collaborative exercises on DNA typing of the Spanish and Portuguese ISFH Working Group. International Society for Forensic Haemogenetics.

Since 1992 the Spanish and Portuguese Working Group (GEP) of the International Society for Forensic Haemogenetics (ISFH) has been organizing collaborative exercises on DNA profiling with the aim of making progress on standardization and discussing technical and statistical problems in DNA analysis. A total of four exercises (GEP-92 to GEP-95) have been carried out until now. A consequence of these exercises was the creation of a quality control programme in Spain and Portugal in 1995 which was carried out simultaneously with the GEP-95 exercise. The number of participating laboratories increased from 10 in the first exercise (GEP-92) to 19 in the last exercise (GEP-95). Despite this increasing number of participating laboratories, results remained satisfactory. In the last exercises, all the laboratories used PCR-based DNA polymorphisms with an increasing number of markers obtaining good results. SLPs were used by only 30% of laboratories in the last two exercises but the results indicated a good level of expertise in most of these laboratories. The reasons for these successful results are the common use of the EDNAP protocol for SLP analysis and commercially available kits or common sequenced allelic ladders for PCR-based DNA polymorphisms.

Report on the third EDNAP collaborative STR exercise. European DNA Profiling Group.

This report describes an inter-laboratory exercise completed on behalf of the European DNA Profiling (EDNAP) group. The exercise is one in a series designated to identify STR loci which could be used for harmonisation between participating European forensic science laboratories. Participants were asked to identify the alleles present in five bloodstains at the STR loci HUMTHO1 and HUMVWFA31/A. Two of the stains were prepared from mixtures of two different blood samples. There were no special instructions and each laboratory was requested to use the methodology normally employed for crime case investigations. All participating laboratories achieved the same results for both loci. In addition, the laboratories were also requested to report the results obtained from any other loci which would normally be used in crime case investigations. A comparison of these results showed some inter-laboratory variation.

Red cell enzymes and plasma protein polymorphisms in the population of Cabo Verde (West Africa).

The genetic polymorphism of six red cell enzymes (ADA, AK1, ALAD, ESD, GLO1, and PGD) and 10 plasma proteins (AHSG, BF, F13A, F13B, GC, HP, ORM, PLG, TBG, and TF) is analyzed in a sample of 268 unrelated individuals from Cabo Verde (West Africa). The population of Cabo Verde was founded in the 15th century (1462), on the basis of a great number of slaves brought from the West African coast and a few Europeans, mainly from Portugal. The frequencies found in Cabo Verde for the majority of the markers are intermediate between those reported for Africans and Europeans. Further, the presence of alleles which are rarely or never seen in Blacks, but are common in Caucasians, suggest a substantial contribution of Europeans to the gene pool of the population of Cabo Verde. © 1995 Wiley-Liss, Inc.