Rosa Espinheira

Portuguese population and paternity investigation studies with a multiplex PCR--the AmpFlSTR Profiler Plus.

A Portuguese Caucasian population of 146 unrelated individuals was studied. DNA samples were amplified by multiplex PCR for D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820 using the AmpFlSTR Profiler Plus PCR Amplification Kit (Perkin-Elmer). All loci met Hardy-Weinberg expectations. Forensic statistical parameters were according to those obtained by other authors. Statistical differences were observed concerning three loci when comparing the Portuguese Caucasian population and an Italian Caucasian population, although these differences mainly concern the less frequent alleles. Eighty-three paternity investigation cases were analysed. Exclusions in between three and nine loci were observed in all the 23 exclusion cases obtained. Most of the non-exclusion cases had probability of paternity > 99.9%. Two cases with an isolated genetic incompatibility between the alleged father and the child were detected, which may indicate probable mutation cases. These results demonstrate that the AmpFlSTR Profiler Plus is a suitable multiplex for paternity investigation in the Portuguese population.

X-Chromosome STR markers data in a Cabo Verde immigrant population of Lisboa

Population genetic data of 12 X chromosomal short tandem repeats markers (DXS10074, DXS10079, DXS10101, DXS10103, DXS10134, DXS10135, DXS10146, DXS10148, DXS7132, DXS7423, DXS8378 and HPRTB) were analysed in 54 females and 95 males of an immigrant population from Cabo Verde living in Lisboa. The obtained results forxa0forensic statistical parameters such as observed heterozigosity, polymorphism information content, power of discrimination and mean exclusion chance, based on single allele frequencies, reveal that this multiplex system is highly informative and can represent an important tool for genetic identification purposes in the immigrant population of Cabo Verde. Since the studied short tandem repeats genetic markers are distributed on four linkage groups, that can provide independent genotype information, we studied those groups as haploytes. The forensic efficiency parameters for the linked groups were all higher than 0.97, with linkage group I being the most polymorphic and linkage group III the less informative.

Genetic portrait of south Portugal population with InDel markers

In human genetic identification the selection of highly polymorphic markers it is very important in order to obtain a high discrimination power even when the number of loci is limited. STR typing continues to be the most robust and reliable method for samples with small amounts of purified and non-degraded DNA. Nonetheless, STR typing has some limitations, such as large amplicon sizes between 150 and 450 base pairs, which can contribute for poor results in challenging forensic samples [1], and also some technical issues like the presence of artefacts, like stutter

Genetic portrait of a native population of Cabo Verde living in Lisboa.

Cabo Verde is an African archipelago located in West Africa coast of the Atlantic Ocean. The country consists of 10 volcanic islands, 9 of them inhabited, and several uninhabited islets. The largest islands are Santiago’s island where is located the capital – Praia, and the island of Santo Antão. Praia is the main human agglomeration of the archipelago. The archipelago was discovered in 1460 by the Portuguese explorer Diogo Gomes, that found the islands uninhabited and without previous evidence of human presence. The Portuguese colonization has begun soon as archipelago discovery being Santiago and Fogo islands the first islands to be populated. According to historical literature colonization took place with caucasian Portuguese men and African slaves. Cabo Verde was a former colony of Portuguese Colonial Empire until 1975, when the independence was proclaimed and the country became formally an independent nation. Culturally, Cabo Verde is characterized by an admixture of European and African elements, which means that it’s not a simple association of two cultures living side by side but a third new product, a third new culture, resulting from an exchange that began about 500 years [1]. According to released data of the Cabo Verde National Institute of Statistics the country had, in 2008, about 500,000 inhabitants. As well as it occurs all over Europe in Portugal and particularly in Lisboa immigrant populations are clearly increasing. According to Portuguese Foreign Affair Services and to the Instituto Nacional de Estatı́stica of Portugal, immigrants from Cabo Verde with fixed residence in Portugal increased from 28,796 up to 43,510 individuals, between 1990 and 2010. From those 43,510 individuals from Cabo Verde, up 34,234 live in Lisboa and near cities or villages. The Combined DNA Index System (CODIS), is a set of autosomal STR loci composed by the markers TPOX, D3S1358, FIBER, D5S818, CSF1PO, D7S820, D8S1179, TH01, VWA, D13S317, D16S539, D18S51, D21S11. Genetic traits combination for this set of markers in a specific individual allows the definition of its own genetic profile. In order to achieve to genetic profiles some other STR markers are commonly used, such as D2S1338, D19S433, Penta D and Penta E [2]. Allowing the definition of individual genetic profiles, simultaneously, some genetic traits, in STR markers, can also be associated with specific populations, or natives of specific regions, or even with specific ethnicities [3,4] To our knowledge there is no published STR genetic data focus on the population of Cabo Verde. Also, no STR genetic data related to emigrant population of Cabo Verde living in Lisboa has been ever published too.

STR mutations in paternity investigations: a study of 1-year consecutive cases

Abstract A study of 1-year consecutive cases for STR mutations has been performed during 2000 with SGM Plus and PowerPlex 1.2 or PowerPlex 16. In paternity investigation cases, 18 STR mutations have been detected in several loci. Paternal and maternal mutation cases and a case with two paternal inconsistencies in D7S820 and CSF1PO are also presented. Maternal and paternal meioses were studied and the average mutation rates concerning several types of mutations were determined. During this 1-year study, multi-banded alleles and vWA genotype differences using different multiplex systems were also detected. The final probability paternity value (after inclusion of mutations) was always >99.99%, allowing to conclude confidently the presence of a mutation.

SOUTH PORTUGUESE POPULATION DATA ON THE LOCI HLA-DQA1, LDLR, GYPA, HBGG, D7S8 AND GC

Five South Portuguese Caucasian subpopulations were analyzed for the HLA-DQA1, LDLR, GYPA, HBGG, D7S8 and Gc loci. Genotype distributions for these loci did not deviate from Hardy-Weinberg expectations. The allele and genotype frequencies found have been compared with previously published data from North and Central Portugal. A total of 11 out of 138 chi-square comparisons of allele frequencies between different Portuguese populations showed a certain degree of divergence. Alentejo, Algarve, Madeira Island and Azores Islands populations might be considered as different groups in a database. For forensic casework, a composite South Portuguese Caucasian population database was obtained for estimating multiple locus profile frequencies using the six PCR-based loci studied.

vWA STR locus structure and variability

Abstract More than 100 vWA alleles were sequenced to detect any possible sequence difference at this locus in Portuguese Caucasian and African populations. Internal variability was detected—the most common structure is TCTA (TCTG)4 (TCTA)n with a TCTA(TCTG)3(TCTA)n structure more frequent in small alleles and a TCTA (TCTG)5–6 (TCTA)n structure predominantly in large ones. Allele 17 has a unique structure in all 20 studied samples and the nonconsensus allele 14 structure has a prevalence of 60% in both populations. Performing more than 3000 paternity investigation cases with multiplex systems, eight vWA mutations were detected with a 0.0024 average mutation rate. Six mutations at the primer-binding site have also been detected when performing ProfilerPlus/SGMPlus versus Powerplex1.2.

A STR mutation in a heteropaternal twin case

A heteropaternal male twin case with two men being alleged fathers was investigated as requested by the Court. Up to 37 PCR-based polymorphic DNA systems were studied in this case which was complicated by a paternal ACTBP2 mutation detected in one twin. This is the first report on a STR mutation in a double paternity case where both biological fathers were indisputably identified. The STR systems enable the resolution of these complex genetic relationships even in a case where a mutation in one STR locus was encountered.

Population Genetics of D1S80, HUMVWFA31/A and HUMF13A1 from Portugal and Goa(India)

Analysis of variable number of tandem repeats (VNTR) loci is widely used for individualization in forensic testing. VNTR locus D1S80 is successfully amplified by PCR. STR loci HUMVWFA31/A and HUMF13A1 are also two informative PCR based identification systems. The aim of this paper is to provide information about estimate allele frequencies for the three loci in Portuguese and Goa (India) populations, due to the Portuguese presence in Goa during four centuries.

Polymarker and HLA DQA1 Genetic Markers in Forensic Casework

Polymarker and HLA DQA1 systems offer new tools for forensic analysis both in identification and in paternity investigation. Polymarker (PM) includes five genetic loci: Low Density Lipoprotein Receptor (LDLR), Glycophorin A (GYPA) and D7S8, each containing two alleles and Hemoglobin G Gammaglobin (HBGG) and Group Specific Component (GC), each containing three alleles. HLA DQA1 polymorphism reveal six major allelic types — DQA1.1, DQA1.2, DQA1.3, DQA2, DQA3 and DQA4.