Browsing by Author "Rosa, Alexandra"
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- African human mtDNA phylogeography at-a-glancePublication . Rosa, Alexandra; Brehm, AntónioThe mitochondrial DNA (mtDNA) genetic system has long proven to be useful for studying the demographic history of our species, since their proposed Southeast/East African origin 200 kya. Despite the weak archaeological and anthropologic records, which render a difficult understanding of early intra continental migrations, the phylogenetic L0-L1’6 split at about 140-160 kya is thought to represent also an early sub-structuring of small and isolated communities in South and East Africa. Regional variation accumulated over the following millennia, with L2 and L3 lineages arising in Central and East Africa 100-75 kya. Their sub-Saharan dispersal not later than 60 kya, largely overwhelmed the L0’1 distribution, nowadays limited to South African Khoisan and Central African Pygmies. Cyclic expansions and retractions of the equatorial forest between 40 kya and the “Last Glacial Aridity Maximum” were able to reduce the genetic diversity of modern humans.. Surviving regional-specific lineages have emerged from the Sahelian refuge areas, repopulating the region and contributing to the overall West African genetic similarity. Particular L1- L3 lineages mirror the substantial population growth made possible by moister and warmer conditions of the Sahara’s Wet Phase and the adoption of agriculture and iron smelting techniques. The diffusion of the farming expertise from a Central African source towards South Africa was mediated by the Bantu people 3 kya. The strong impact of their gene flow almost erased the pre-existent maternal pool. Non-L mtDNAs testify for Eurasian lineages that have enriched the African maternal pool at different timeframes: i) Near and Middle Eastern influences in Upper Palaeolithic, probably link to the spread of Afro-Asiatic languages; ii) particular lineages from West Eurasia around or after the glacial period; iii) post-glacial mtDNA signatures from the Franco-Cantabrian refugia, that have crossed the Strait of Gibraltar and iv) Eurasian lineages tracing back to the Neolithic or more recent historical episodes. Finally, the non-random sub-Saharan spread of North African lineages was likely mediated by the ancestors of Fulani, nomadic pastoral communities in the Sahel.
- Africans in Yorkshire? The deepest-rooting clade of the Y phylogeny within an english genealogyPublication . King, Turi E; Parkin, Emma J; Swinfield, Geoff; Cruciani, Fulvio; Scozzari, Rosaria; Rosa, Alexandra; Lim, Si-Keun; Xue, Yali; Tyler-Smith, Chris; Jobling, Mark AThe presence of Africans in Britain has been recorded since Roman times, but has left no apparent genetic trace among modern inhabitants. Y chromosomes belonging to the deepest-rooting clade of the Y phylogeny, haplogroup (hg) A, are regarded as African-specific, and no examples have been reported from Britain or elsewhere in Western Europe. We describe the presence of an hgA1 chromosome in an indigenous British male; comparison with African examples suggests a Western African origin. Seven out of 18 men carrying the same rare east-Yorkshire surname as the original male also carry hgA1 chromosomes, and documentary research resolves them into two genealogies with most-recent-common-ancestors living in Yorkshire in the late 18th century. Analysis using 77 Y-short tandem repeats (STRs) is consistent with coalescence a few generations earlier. Our findings represent the first genetic evidence of Africans among ‘indigenous’ British, and emphasize the complexity of human migration history as well as the pitfalls of assigning geographical origin from Y-chromosomal haplotypes
- Analysis of Y-chromosome and mtDNA variability in the Madeira Archipelago populationPublication . Fernandes, Ana T.; Gonçalves, Rita; Rosa, Alexandra; Brehm, AntónioThe Atlantic archipelago of Madeira is made up of two islands (Madeira and Porto Santo) with 250,000 inhabitants. These islands were discovered and settled by the Portuguese in the 15th century and played an important role in the complex Atlantic trade network in the following centuries. The genetic composition of the Madeira Islands’ population was investigated by analyzing Y-chromosomal bi-allelic and STR markers in three different regions of the main island plus Porto Santo. We compared the results with mtDNA data and used the Y-chromosome STRs to determine the variability within each haplogroup. A sample of 142 unrelated males divided into four groups (Funchal City, West Madeira, North and East Madeira and Porto Santo) were analyzed. Significant genetic differences between these regions and the population of Funchal were found. The population of Funchal had lower gene diversity than expected.
- Asthma: snapshot or motion picture?Publication . Brehm, António; Rosa, Alexandra; Berenguer, Anabela G.
- Convergence of miRNA expression profiling, α-synuclein interacton and GWAS in Parkinson's diseasePublication . Martins, Madalena; Rosa, Alexandra; Guedes, Leonor C.; Fonseca, Benedita V.; Gotovac, Kristina; Violante, Sara; Mestre, Tiago; Coelho, Miguel; Rosa, Mário M.; Martin, Eden R.; Vance, Jeffery M.; Outeiro, Tiago F.; Wang, Liyong; Borovecki, Fran; Ferreira, Joaquim J.; Oliveira, Sofia A.miRNAs were recently implicated in the pathogenesis of numerous diseases, including neurological disorders such as Parkinson’s disease (PD). miRNAs are abundant in the nervous system, essential for efficient brain function and play important roles in neuronal patterning and cell specification. To further investigate their involvement in the etiology of PD, we conducted miRNA expression profiling in peripheral blood mononuclear cells (PBMCs) of 19 patients and 13 controls using microarrays. We found 18 miRNAs differentially expressed, and pathway analysis of 662 predicted target genes of 11 of these miRNAs revealed an over-representation in pathways previously linked to PD as well as novel pathways. To narrow down the genes for further investigations, we undertook a parallel approach using chromatin immunoprecipitation-sequencing (ChIP-seq) analysis to uncover genome-wide interactions of a-synuclein, a molecule with a central role in both monogenic and idiopathic PD. Convergence of ChIP-seq and miRNomics data highlighted the glycosphingolipid biosynthesis and the ubiquitin proteasome system as key players in PD. We then tested the association of target genes belonging to these pathways with PD risk, and identified nine SNPs in USP37 consistently associated with PD susceptibility in three genome-wide association studies (GWAS) datasets (0.46#OR#0.63) and highly significant in the meta-dataset (3.3661024 ,p,1.9461023 ). A SNP in ST8SIA4 was also highly associated with PD (p = 6.1561023 ) in the meta-dataset. These findings suggest that several miRNAs may act as regulators of both known and novel biological processes leading to idiopathic PD.
- DAZ gene copies: evidence of Y chromosome evolutionPublication . Fernandes, Ana Teresa; Fernandes, Susana; Gonçalves, Rita; Sá, Rosália; Costa, Paula; Rosa, Alexandra; Farrás, Cristina; Sousa, Mário; Brehm, António; Barros, AlbertoThe DAZ gene, a contributing factor in infertility, lies on the human Y chromosome's AZFc region, whose deletion is a common cause of spermatogenic failure. Y chromosome binary polymorphisms on the non-recombining Y (NRY) region, believed to be a single occurrence on an evolutionary scale, were typed in a sample of fertile and infertile men with known DAZ backgrounds. The Y single-nucleotide polymorphisms (Y-SNPs) with low mutation rates are currently well characterized and permit the construction of a unique phylogeny of haplogroups. DAZ haplotypes were defined using single-nucleotide variant (SNV)/sequence tagged-site (STS) markers to distinguish between the four copies of the gene. The variation of 10 Y chromosome short tandem repeat (STRs) was used to determine the coalescence age of DAZ haplotypes in a comparable time frame similar to that of SNP haplogroups. An association between DAZ haplotypes and Y chromosome haplogroups was found, and our data show that the DAZ gene is not under selective constraints and its evolution depends only on the mutation rate. The same variants were common to fertile and infertile men, although partial DAZ deletions occurred only in infertile men, suggesting that those should only be used as a tool for infertility diagnosis when analysed in combination with haplogroup determinations.
- Ethiopian mitochondrial DNA heritage: tracking gene flow across and around the gate of tearsPublication . Kivisild, Toomas; Reidla, Maere; Metspalu, Ene; Rosa, Alexandra; Brehm, António; Pennarun, Erwan; Parik, Jüri; Geberhiwot, Tarekegn; Usanga, Esien; Villems, RichardApproximately 10 miles separate the Horn of Africa from the Arabian Peninsula at Bab-el-Mandeb (the Gate of Tears). Both historic and archaeological evidence indicate tight cultural connections, over millennia, between these two regions. High-resolution phylogenetic analysis of 270 Ethiopian and 115 Yemeni mitochondrial DNAs was performed in a worldwide context, to explore gene flow across the Red and Arabian Seas. Nine distinct subclades, including three newly defined ones, were found to characterize entirely the variation of Ethiopian and Yemeni L3 lineages. Both Ethiopians and Yemenis contain an almost-equal proportion of Eurasian-specific M and N and African-specific lineages and therefore cluster together in a multidimensional scaling plot between Near Eastern and sub-Saharan African populations. Phylogeographic identification of potential founder haplotypes revealed that approximately one-half of haplogroup L0-L5 lineages in Yemenis have close or matching counterparts in southeastern Africans, compared with a minor share in Ethiopians. Newly defined clade L6, the most frequent haplogroup in Yemenis, showed no close matches among 3,000 African samples. These results highlight the complexity of Ethiopian and Yemeni genetic heritage and are consistent with the introduction of maternal lineages into the South Arabian gene pool from different source populations of East Africa. A high proportion of Ethiopian lineages, significantly more abundant in the northeast of that country, trace their western Eurasian origin in haplogroup N through assorted gene flow at different times and involving different source populations.
- Genetic polymorphisms and asthma: findings from a case–control study in the Madeira island populationPublication . Berenguer, Anabela; Fernandes, Ana; Oliveira, Susana; Rodrigues, Mariana; Ornelas, Pedro; Romeira, Diogo; Serrão, Tânia; Rosa, Alexandra; Câmara, RitaBackground: Asthma is a complex disease influenced by multiple genetic and environmental factors. While Madeira has the highest prevalence of asthma in Portugal (14.6%), the effect of both genetic and environmental factors in this population has never been assessed. We categorized 98 asthma patients according to the Global Initiative for Asthma (GINA) guidelines, established their sensitization profile, and measured their forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) indexes. Selected single nucleotide polymorphisms (SNPs) were analysed as potential markers for asthma susceptibility and severity in the interleukin 4 (IL4), interleukin 13 (IL13), beta-2-adrenergic receptor (ADRB2), a disintegrin and metalloprotease 33 (ADAM33), gasdermin-like (GSDML) and the signal transducer and activator of transcription 6 (STAT6) genes comparatively to a population reference set. Results: Although mites are the major source of allergic sensitization, no significant difference was found amongst asthma severity categories. IL4-590*CT/TT and IL4-RP2*253183/183183 were found to predict the risk (2-fold) and severity (3 to 4-fold) of asthma and were associated with a lower FEV1 index. ADRB2-c.16*AG is a risk factor (3.5-fold), while genotype GSDML-236*TT was protective (4-fold) for moderate-severe asthma. ADAM33-V4*C was associated to asthma and mild asthma by the transmission disequilibrium test (TDT). Finally, ADAM33-V4*CC and STAT6-21*TT were associated with higher sensitization (mean wheal size ≥10 mm) to house dust (1.4-fold) and storage mite (7.8-fold). Conclusion: In Madeira, IL4-590C/T, IL4-RP2 253/183, GSDML-236C/T and ADAM33-V4C/G SNPs are important risk factors for asthma susceptibility and severity, with implications for asthma healthcare management.
- Mitochondrial genome association study with peripheral arterial disease and venous thromboembolismPublication . Abrantes, Patrícia; Rosa, Alexandra; Francisco, Vânia; Sousa, Inês; Xavier, Joana M.; Oliveira, Sofia A.Background and aims: Peripheral arterial disease (PAD) and venous thromboembolism (VTE) are vascular traits sharing common modifiable and non-modifiable risk factors. These vascular pathologies have known nuclear-encoded genetic risk factors and the mitochondrial DNA may account for part of the missing heritability. To determine if PAD and VTE have a dual genetic control (mitochondrial and nu clear), we hereby investigated the association of mitochondrial DNA polymorphisms and haplogroups with these vascular traits. Methods: The association of mitochondrial single nucleotide polymorphisms (mtSNPs) and haplogroups was tested in 1652 PAD cases and 1629 controls from the eMERGE PAD genome-wide association study (GWAS), and 1241 VTE cases and 1278 controls from the GENEVA GWAS of venous thrombosis (dbGaP accession numbers phs000203.v1.p1 and phs000289.v2.p1, respectively). Results: 66 and 72 mtSNPs passed quality control filters and were tested for association with PAD and VTE, respectively. Significant evidence of population stratification could not be detected in both datasets. Three mtSNPs (m.477T > C, m.9667A > G, and m.10915T > C) were nominally associated (3.01 10 3 pa 3.96 10 2 ) with PAD in the logistic regression adjusted for confounding factors, and m.11914G > A was nominally associated (pa ¼ 4.14 10 2 ) with VTE. None of the nine major mito chondrial haplogroups were associated with either PAD or VTE. Conclusion: Unlike other vascular diseases such as stroke and diabetes, these results suggest that com mon mitochondrial variants individually or in combination do not play a major role in PAD and VTE susceptibility.
- Mitochondrial haplogroup H1 is protective for ischemic stroke in portuguese patientsPublication . Rosa, Alexandra; Fonseca, Benedita V.; Krug, Tiago; Manso, Helena; Gouveia, Liliana; Albergaria, Isabel; Gaspar, Gisela; Correia, Manuel; Viana-Baptista, Miguel; Simões, Rita Moiron; Pinto, Amélia Nogueira; Taipa, Ricardo; Ferreira, Carla; Fontes, João Ramalho; Silva, Mário Rui; Gabriel, João Paulo; Matos, Ilda; Lopes, Gabriela; Ferro, José M; Vicente, Astrid M; Oliveira, Sofia A.Background: The genetic contribution to stroke is well established but it has proven difficult to identify the genes and the disease-associated alleles mediating this effect, possibly because only nuclear genes have been intensely investigated so far. Mitochondrial DNA (mtDNA) has been implicated in several disorders having stroke as one of its clinical manifestations. The aim of this case-control study was to assess the contribution of mtDNA polymorphisms and haplogroups to ischemic stroke risk. Methods: We genotyped 19 mtDNA single nucleotide polymorphisms (SNPs) defining the major European haplogroups in 534 ischemic stroke patients and 499 controls collected in Portugal, and tested their allelic and haplogroup association with ischemic stroke risk. Results: Haplogroup H1 was found to be significantly less frequent in stroke patients than in controls (OR = 0.61, 95% CI = 0.45–0.83, p = 0.001), when comparing each clade against all other haplogroups pooled together. Conversely, the pre-HV/HV and U mtDNA lineages emerge as potential genetic factors conferring risk for stroke (OR = 3.14, 95% CI = 1.41–7.01, p = 0.003, and OR = 2.87, 95% CI = 1.13–7.28, p = 0.021, respectively). SNPs m.3010G>A, m.7028C>T and m.11719G>A strongly influence ischemic stroke risk, their allelic state in haplogroup H1 corroborating its protective effect. Conclusion: Our data suggests that mitochondrial haplogroup H1 has an impact on ischemic stroke risk in a Portuguese sample