Elzemar Martins Ribeiro Rodrigues

A multiplex PCR for 11 X chromosome STR markers and population data from a Brazilian Amazon Region

The analysis of X-STR polymorphisms has received the attention of several researchers, mainly due to its applicability to the investigation of complex kinship cases. Although many X-STRs have been validated for forensic use, little is known about the variations of these polymorphisms in different populations of the world. The present work describes a new multiplex system that allows the simultaneous analysis of 11 X-STR markers, for use both in paternity determination and more complex forensic cases. The loci investigated include DXS9895, DXS7132, DXS6800, DXS9898, DXS6789, DXS7133, DXS7130, HPRTB, GATA31E08, DXS7423, and DXS10011, which together afford a power of discrimination in the order of 0.999999. In addition, this work presents the genotyping results obtained for a sample of 324 individuals (182 males and 142 females) from the admixed population of Belém, Pará, located in the Brazilian Amazon Region.

Insertion–deletion polymorphisms—utilization on forensic analysis

Insertion–deletion (INDEL) markers are very frequent in the human genome and present several advantages for population and forensic studies, such as low mutation rates, easy interpretation, small amplicons, easy genotyping, and the possibility of using multiplex PCR. The great adaptability of INDELs for amplification of low copy number or degraded DNA allows its using as an interesting platform of genetic identity by DNA in forensic cases. In the present study, we tested the ability of 48 diallelic INDEL markers on genotyping forensic samples collected from different biological samples related to criminal cases. Moreover, we evaluated the lowest DNA concentration with which there was amplification of all markers from each one of three indel-plex panels. When comparing the performances obtained by the indel-plex panels described in this study with results obtained using Identifiler® kit (Applied Biosystems) related to forensic samples, as well as to control samples with different concentrations of DNA, we observed superior efficiency on samples with low copy number or in the presence of inhibitors.

Estimates of Interethnic Admixture in the Brazilian Population Using a Panel of 24 X-Linked Insertion/Deletion Markers

Objectives. In this study, we aimed to identify ancestry informative haplotypes and make interethnic admixture estimates using X‐chromosome markers.

A study of GJB2 and delGJB6-D13S1830 mutations in Brazilian non-syndromic deaf children from the Amazon region

UNLABELLED Hearing impairment affects about 1 in 1000 newborns. Mutations in the connexin 26 (GJB2) gene rank among the most frequent causes of non-syndromic deafness in different populations, while delGJB6-D13S1830 mutation located in the DFNB30 locus is known to cause sensorineural hearing loss. Despite the many studies on the involvement of GJB2 mutations in hearing impairment in different populations, there is little information on genetic deafness in Brazil, especially in the Amazon region. OBJECTIVE To determine the prevalence of GJB2 mutations and delGJB6-D13S1830 in 77 sporadic non-syndromic deaf patients. METHOD The coding region of the GJB2 gene was sequenced and polymerase chain reaction was performed to detect the delGJB6-D13S1830 mutation. RESULTS Mutant allele 35delG was found in 9% of the patients (7/77). Mutations M34T and V95M were detected in two distinct heterozygous patients. Non-pathogenic mutation V27I was detected in 28.6% of the patients (22/77). None of the deaf patients carried the delGJB6-D13S1830 mutation. CONCLUSION Mutant alleles on gene GJB2 were observed in 40% (31/77) of the subjects in the sample. Pathogenic variants were detected in only 12% (9/77) of the individuals. More studies are required to elucidate the genetic causes of hearing loss in miscegenated populations.

Allelic frequencies and statistical data obtained from 12 codis STR loci in an admixed population of the Brazilian Amazon

The allelic frequencies of 12 short tandem repeat loci were obtained from a sample of 307 unrelated individuals living in Macapá, a city in the northern Amazon region, Brazil. These loci are the most commonly used in forensics and paternity testing. Based on the allele frequency obtained for the population of Macapá, we estimated an interethnic admixture for the three parental groups (European, Native American and African) of, respectively, 46%, 35% and 19%. Comparing these allele frequencies with those of other Brazilian populations and of the Iberian Peninsula population, no significant distances were observed. The interpopulation genetic distances (FST coefficients) to the present database ranged from FST = 0.0016 between Macapá and Belém to FST = 0.0036 between Macapá and the Iberian Peninsula.

Y-STR haplotypes of Native American populations from the Brazilian Amazon region

The allele and haplotype frequencies of nine Y-STRs (DYS19, DYS389 I, DYS389 II, DYS390, DYS391, DYS392, DYS393, DYS385 I/II) were determined in a sample of six native tribes from the Brazilian Amazon (Tiriyó, Awa-Guajá, Waiãpi, Urubu-Kaapor, Zoé and Parakanã). Forty-eight different haplotypes were identified, 28 of which unique. Five haplotypes are very frequent and were shared by over 10 individuals. The estimated haplotype diversity (0.9114) was very low compared to other geographic groups, including Africans, Europeans and Asians.

Genetic data of twelve X-STRs in a Japanese immigrant population resident in Brazil

In the last years, several works have been published on the variability of X-markers; however, few were on Asian populations. In this work, we present the genetic data of 12 X-STRs (DXS9895, DXS7132, DXS6800, DXS9898, DXS6789, DXS7133, GATA172D05, DXS7130, HPRTB, GATA31E08, DXS7423, DXS10011) obtained from a sample of 232 individuals of Japanese origin residing in Brazil. Most markers investigated present a high genetic diversity, with the exception of DXS6800. No deviations from Hardy-Weinberg equilibrium were observed, with the exception of DXS7133 locus. Linkage disequilibrium analysis did not reveal consistent evidence of association between the X-STRs used. The comparison of the Japanese immigrant population with other Asian populations (Japanese, Chinese, and Korean) demonstrates the inexistence of significant allelic frequency differences between these populations in most systems investigated.

Population genetic analysis of insertion–deletion polymorphisms in a Brazilian population using the Investigator DIPplex kit

The aim of this study was to estimate the diversity of 30 insertion/deletion (INDEL) markers (Investigator(®) DIPplex kit) in a sample of 519 individuals from six Brazilian states and to evaluate their applicability in forensic genetics. All INDEL markers were found to be highly polymorphic in the Brazilian population and were in Hardy-Weinberg equilibrium. To determine their forensic suitability in the Brazilian population, the markers were evaluated for discrimination power, match probability and exclusion power. The combined discrimination power (CDP), combined match power (CMP) and combined power of exclusion (CPE) were higher than 0.999999, 3.4 × 10(-13) and 0.9973, respectively. Further comparison of 29 worldwide populations revealed significant genetic differences between continental populations and a closer relationship between the Brazilian and European populations.