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.

In a collaborative work carried out by the Spanish and Portuguese ISFG Working Group (GEP-ISFG), a polymerase chain reaction multiplex was optimized in order to type ten X-chromosome short tandem repeats (STRs) in a single reaction, including: DXS8378, DXS9902, DXS7132, DXS9898, DXS6809, DXS6789, DXS7133, GATA172D05, GATA31E08, and DXS7423. Using this X-decaplex, each 17 of the participating laboratories typed a population sample of approximately 200 unrelated individuals (100 males and 100 females). In this work, we report the allele frequencies for the ten X-STRs in 15 samples from Argentina (Buenos Aires, Córdoba, Río Negro, Entre Ríos, and Misiones), Brazil (São Paulo, Rio de Janeiro, Paraná, and Mato Grosso do Sul), Colombia (Antioquia), Costa Rica, Portugal (Northern and Central regions), and Spain (Galicia and Cantabria). Gene diversities were calculated for the ten markers in each population and all values were above 56%. The average diversity per locus varied between 66%, for DXS7133, and 82%, for DXS6809. For this set of STRs, a high discrimination power was obtained in all populations, both in males (> or =1 in 5 x 10(5)) and females (> or =1 in 3 x 10(9)), as well as high mean exclusion chance in father/daughter duos (> or =99.953%) and in father/mother/daughter trios (> or =99.999%). Genetic distance analysis showed no significant differences between northern and central Portugal or between the two Spanish samples from Galicia and Cantabria. Inside Brazil, significant differences were found between Rio de Janeiro and the other three populations, as well as between São Paulo and Paraná. For the five Argentinean samples, significant distances were only observed when comparing Misiones with Entre Ríos and with Río Negro, the only two samples that do not differ significantly from Costa Rica. Antioquia differed from all other samples, except the one from Río Negro.

SummaryThe clinal pattern observed for the distribution of Y-chromosome lineages in Europe is not always reflected at a geographically smaller scale. Six hundred and sixty-three male samples from the 18 administrative districts of Portugal were typed for 25 Y-chromosome biallelic and 15 microsatellite markers, in order to assess the degree of substructuring of male lineage distribution. Haplogroup frequency distributions, Analysis of Molecular Variance (AMOVA) and genetic distance analyses at both Y-SNP and Y-STR levels revealed a general genetic homogeneity of Portuguese sub-populations. The traditional division of the country in north, central and south, which is usually considered in studies addressing questions of the genetic variation distribution in Portugal, was not reflected in the Y-haplotype distribution. Instead, just one sub-region (Alentejo) stood out due to the presence of high diversity levels and a higher number of different lineages, at higher frequencies than in other regions. These results are reconciled with the historical evidence available, assuming that from prehistorical times down to the end of the medieval period this region harboured the most diverse groups of people and, because of economic depression, remained relatively isolated from recent homogenisation movements. The finding of a broadly homogeneous background for the Portuguese population has vast repercussions in forensic, epidemiological and association studies.

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An X-chromosomal multiplex amplifying ten short tandem repeats (STRs) in one single PCR reaction was developed and optimized in this work. The X-STRs included were DXS8378, DXS9898, DXS8377, HPRTB, GATA172D05, DXS7423, DXS6809, DXS7132, DXS101, and DXS6789. Decaplex performance was tested on 377 male samples from three United States population groups, namely, 130 African Americans, 104 Asians, and 143 Hispanics. DXS8377 was the most polymorphic locus across all three populations, whereas DXS7423 was the least informative marker. Genetic distance analysis (R (ST) and F (ST)) performed for the three populations residing in New York showed significant genetic distances between population groups for most pairwise comparisons, except for HPRTB, DXS6809, and DXS7132. When testing linkage disequilibrium for all pairs of loci in the three groups, no significant association was found between any pair of the loci studied, after applying Bonferroni correction. The high values for the average probability of excluding a random man obtained in all three populations when both mother and daughter are tested or when father/daughter relationships are evaluated support the potential of this decaplex system in kinship analysis. Also, the overall high power of discrimination values for samples of female and male origin, confirms the usefulness of this decaplex system in identification analysis. As expected, results also support the use of independent databases comprising these ten X-linked loci for the three US populations evaluated.

Studies of human genetic variation predominantly use short tandem repeats (STRs) and single nucleotide polymorphisms (SNPs) but Insertion deletion polymorphisms (Indels) are being increasingly explored. They combine desirable characteristics of other genetic markers, especially the possibility of being analysed using short amplicon strategies, which increases the ease of analysis, contributing to justify their interest in population and forensic genetics. After the advent of autosomal and uniparental genomes (mtDNA and Y chromosome), these fields of research are also focusing on the X chromosome, given its special transmission pattern. The X chromosome markers brought new insights into the history of modern human populations and also proved useful in forensic kinship investigations, namely in deficient relationship cases and in cases where autosomes are uninformative. This work describes an X-Indel multiplex system amplifying 32 biallelic markers in one single PCR. The multiplex includes X-Indels shown to be polymorphic in the major human population groups and follows a short amplicon strategy. The set was applied in the genetic characterization of sub-Saharan African, European and East Asian population samples and revealed high forensic efficiency, as measured by the accumulated power of discrimination (0.9999990 was the lowest value in males and 0.999999999998 was the highest in females) and mean exclusion chance varied between 0.998 and 0.9996 in duos and between 0.99997 and 0.999998 in trios. Finally, a segregation analysis was performed using trio constellations of father-mother-daughters in order to address the transmission pattern and assess mutation rates of this type of markers.

The European DNA Profiling Group (EDNAP) organized a fourth and fifth collaborative exercise on RNA/ DNA co-analysis for body fluid identification and STR profiling. The task was to identify dried menstrual blood and vaginal secretion stains using specific RNA biomarkers, and additionally test 3 housekeeping genes for their suitability as reference genes. Six menstrual blood and six vaginal secretion stains, two dilution series (1/4-1/64 pieces of a menstrual blood/vaginal swab) and, optionally, bona fide or mock casework samples of human or non-human origin were analyzed by 24 participating laboratories, using RNA extraction or RNA/DNA co-extraction methods. Two novel menstrual blood mRNA multiplexes were used: MMP triplex (MMP7, MMP10, MMP11) and MB triplex (MSX1, LEFTY2, SFRP4) in conjunction with a housekeeping gene triplex (B2M, UBC, UCE). Two novel mRNA multiplexes and a HBD1 singleplex were

Genetic data of 10 X chromosome STRs (DXS8378, DXS9898, DXS8377, HPRTB, GATA172D05, DXS7423, DXS6809, DXS7132, DXS101 and DXS6789) were obtained in a sample of unrelated males born in the five northern Portuguese districts. In a global sample of 347 individuals, no shared haplotypes were found for this set of markers and single locus gene diversities were high, varying between 0.678 for DXS7423 and 0.921 for DXS8377. Linkage disequilibrium analysis did not reveal consistent evidence of association between the X-STRs used. Population comparisons of northern Portuguese districts (exact test of population differentiation; pairwise genetic distances) and analysis of molecular variance supported genetic homogeneity of this region and therefore a common genetic database was considered. In comparisons with other European data, the only population samples showing statistically significant differences to northern Portugal were Germany and Latvia. The present work demonstrates that these genetic markers are highly discriminating and therefore useful for human identification purposes and anthropological research.