Genetic characterization of an X-STR decaplex system in the State of Mato Grosso, Brazil: distribution, forensic efficiency and population structure.

Studies with X-STR loci show population genetic substructure, which makes necessary the characterization of such markers in the different geographical and/or ethnic populations. Therefore, this study assessed the distribution and forensic efficiency of an X-STR decaplex system in the population of the State of Mato Grosso, as well as analysed the population structure of this State based on the aforementioned system. All X-STR markers were in Hardy-Weinberg equilibrium and linkage equilibrium, and the DXS6809 was the most informative marker.

Male-specific contributions to the Brazilian population of Espirito Santo.

Y chromosome markers have been widely studied due to their various applications in the fields of forensic and evolutionary genetics. In this study, 35 Y-SNPs and 17 Y-STRs were genotyped in 253 males from the State of Espirito Santo, Brazil. A total of 18 haplogroups and 243 haplotypes were detected; the haplogroup and haplotype diversities were 0.

Brazilian genetic database of chromosome X.

The X chromosome is a singular source of information in population genetics, anthropological research and in forensic cases. Thus, many researchers have been interested in characterizing X chromosome markers in different populations. The Brazilian Genetic Database of Chromosome X (BGBX--Banco Genético Brasileiro do Cromossomo X) website is freely available in Portuguese and English versions and was developed with the main purpose of compiling all Brazilian population genetic data for X chromosome short tandem repeats (X-STRs) markers published in scientific journals searchable via PubMed.

Genetic data of 15 autosomal STR loci: an analysis of the Araraquara population colonization (São Paulo, Brazil).

The genetic markers most commonly utilized to determine identity and in paternity testing are autosomal short tandem repeats (STRs); to interpret the DNA analysis, the results of a case have to be compared with a pertinent reference population. Thus, the aim of this work was to characterize the genetic profile of the population of Araraquara (São Paulo, Brazil) by analyzing 15 STR loci included in the PowerPlex(®) 16 System and to correlate these data with the migration history of the population. No deviations from the Hardy-Weinberg equilibrium were observed for any of the loci, after Bonferroni's correction.

A single multiplex PCR and SNaPshot minisequencing reaction of 42 SNPs to classify admixture populations into mitochondrial DNA haplogroups.

SNaPshot minisequencing reaction is in increasing use because of its fast detection of many polymorphisms in a single assay. In this work we described a highly sensitive single nucleotide polymorphisms (SNPs) typing method with detection of 42 mitochondrial DNA (mtDNA) SNPs in a single PCR and SNaPshot multiplex reaction, in order to allow haplogroup classification in Latin American admixture population. We validated the panel typing 160 Brazilian individuals.

No relationship found between point heteroplasmy in mitochondrial DNA control region and age range, sex and haplogroup in human hairs.

The analysis of heteroplasmy (presence of more than one type of mitochondrial DNA in an individual) is used as a tool in human identification studies, anthropology, and most currently in studies that relate heteroplasmy with longevity. The frequency of heteroplasmy and its correlation with age has been analyzed using different tissues such as blood, muscle, heart, bone and brain and in different regions of mitochondrial DNA, but this analysis had never been performed using hair samples. In this study, samples of hair were sequenced in order to ascertain whether the presence or not of heteroplasmy varied according to age, sex and origin of haplogroup individuals.

Genetic profile characterization of 10 X-STRs in four populations of the southeastern region of Brazil.

Ten X-chromosomal short tandem repeats (DXS8378, DXS9902, DXS7132, DXS9898, DXS6809, DXS6789, DXS7133, GATA172D05, GATA31E08 and DXS7423) were analyzed in four populations of the southeastern region of Brazil (São Paulo, Rio de Janeiro, Vitória and Belo Horizonte). No deviations from the Hardy-Weinberg equilibrium were observed for any of the analyzed loci in the four populations. The average diversity per locus varied between 68% for DXS8378, DXS7133, and DXS7423 and 83%, for DXS6809, with Rio de Janeiro being the most diverse population.

Heteroplasmy in hair: study of mitochondrial DNA third hypervariable region in hair and blood samples.

Mitochondrial DNA (mtDNA) analysis has proved useful for forensic identification especially in cases where nuclear DNA is not available, such as with hair evidence. Heteroplasmy, the presence of more than one type of mtDNA in one individual, is a common situation often reported in the first and second mtDNA hypervariable regions (HV1/HV2), particularly in hair samples. However, there is no data about heteroplasmy frequency in the third mtDNA hypervariable region (HV3).

X-chromosome genetic variation in São Paulo State (Brazil) population.

As data on X-chromosomal short tandem repeats (X-STRs) for the Brazilian population are scarse, the aim of this study was to determine the allele frequencies of five X-STRs (DXS6854, DXS7424, DXS101, DXS6808 and DXS7132) in the São Paulo State, Brazil. No deviations from the Hardy-Weinberg equilibrium were observed, with the exception of DXS101. The forensic efficiency parameters demonstrated that DXS101 was the most informative marker.

Heteroplasmy in hair: differences among hair and blood from the same individuals are still a matter of debate.

The analysis of mitochondrial DNA (mtDNA) is a useful tool in forensic cases when sample contents too little or degraded nuclear DNA to genotype by autosomal short tandem repeat (STR) loci, but it is especially useful when the only forensic evidence is a hair shaft. Several authors have related differences in mtDNA from different tissues within the same individual, with high frequency of heteroplasmic variants in hair, as also in some other tissues. Is still a matter of debate how the differences influence the interpretation forensic protocols.