167 research outputs found
Evolutionary dynamics of the human pseudoautosomal regions
Recombination between the X and Y human sex chromosomes is limited to the two pseudoautosomal regions (PARs) that present quite distinct evolutionary origins. Despite the crucial importance for male meiosis, genetic diversity patterns and evolutionary dynamics of these regions are poorly understood. In the present study, we analyzed and compared the genetic diversity of the PAR regions using publicly available genomic sequences encompassing both PAR1 and PAR2. Comparisons were performed through allele diversities, linkage disequilibrium status and recombination frequencies within and between X and Y chromosomes. In agreement with previous studies, we confirmed the role of PAR1 as a male-specific recombination hotspot, but also observed similar characteristic patterns of diversity in both regions although male recombination occurs at PAR2 to a much lower extent (at least one recombination event at PAR1 and in ˜1% in normal male meioses at PAR2). Furthermore, we demonstrate that both PARs harbor significantly different allele frequencies between X and Y chromosomes, which could support that recombination is not sufficient to homogenize the pseudoautosomal gene pool or is counterbalanced by other evolutionary forces. Nevertheless, the observed patterns of diversity are not entirely explainable by sexually antagonistic selection. A better understanding of such processes requires new data from intergenerational transmission studies of PARs, which would be decisive on the elucidation of PARs evolution and their role in male-driven heterosomal aneuploidies.This work was supported by: - FEDER - Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 - Operacional Programme for Competitiveness and Internationalization (POCI), Portugal 2020. - Fundação para a Ciência e a Tecnologia, in the framework of the Project POCI-01–0145-FEDER-007274 to i3S. - Fundação para a Ciência e a Tecnologia, in the PhD fellowship SFRH/BD/ 135612/2018 to B.M. - Ministerio de Ciencia, Innovación y Universidades, in the Grant “Ramón y Cajal” RYC-2015-18241 to M.A. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Evolutionary Constraints in the b-Globin Cluster: The Signature of Purifying Selection at the d-Globin (HBD) Locus and Its Role in Developmental Gene Regulation
Human hemoglobins, the oxygen carriers in the blood, are composed by two α-like and two β-like globin monomers. The β-globin gene cluster located at 11p15.5 comprises one pseudogene and five genes whose expression undergoes two critical switches: the embryonic-to-fetal and fetal-to-adult transition. HBD encodes the δ-globin chain of the minor adult hemoglobin (HbA2), which is assumed to be physiologically irrelevant. Paradoxically, reduced diversity levels have been reported for this gene. In this study, we sought a detailed portrait of the genetic variation within the β-globin cluster in a large human population panel from different geographic backgrounds. We resequenced the coding and noncoding regions of the two adult β-globin genes (HBD and HBB) in European and African populations, and analyzed the data from the β-globin cluster (HBE, HBG2, HBG1, HBBP1, HBD, and HBB) in 1,092 individuals representing 14 populations sequenced as part of the 1000 Genomes Project. Additionally, we assessed the diversity levels in nonhuman primates using chimpanzee sequence data provided by the PanMap Project. Comprehensive analyses, based on classic neutrality tests, empirical and haplotype-based studies, revealed that HBD and its neighbor pseudogene HBBP1 have mainly evolved under purifying selection, suggesting that their roles are essential and nonredundant. Moreover, in the light of recent studies on the chromatin conformation of the β-globin cluster, we present evidence sustaining that the strong functional constraints underlying the decreased contemporary diversity at these two regions were not driven by protein function but instead are likely due to a regulatory role in ontogenic switches of gene expression
Genetic variability of the functional domains of chromodomains helicase DNA-binding (CHD) proteins
In the past few years, there has been an increasing neuroscientific interest in understanding the function of mammalian chromodomains helicase DNA-binding (CHD) proteins due to their association with severe developmental syndromes. Mammalian CHDs include nine members (CHD1 to CHD9), grouped into subfamilies according to the presence of specific functional domains, generally highly conserved in evolutionary terms. Mutations affecting these domains hold great potential to disrupt protein function, leading to meaningful pathogenic scenarios, such as embryonic defects incompatible with life. Here, we analysed the evolution of CHD proteins by performing a comparative study of the functional domains of CHD proteins between orthologous and paralogous protein sequences. Our findings show that the highest degree of inter-species conservation was observed at Group II (CHD3, CHD4, and CHD5) and that most of the pathological variations documented in humans involve amino acid residues that are conserved not only between species but also between paralogs. The parallel analysis of both orthologous and paralogous proteins, in cases where gene duplications have occurred, provided extra information showing patterns of flexibility as well as interchangeability between amino acid positions. This added complexity needs to be considered when the impact of novel mutations is assessed in terms of evolutionary conservation.This research was funded by FEDER—Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020—Operacional Programme for Competitiveness and Internationalization (POCI), Portugal 2020, and by Portuguese funding through FCT—Fundação para a Ciência e a Tec-nologia, within the framework of the Project POCI-01–0145-FEDER-007274 to i3S and by FCT research project POCI-01–0145-FEDER-29723. ARC holds a FCT PhD Fellowship (SFRH/BD/141702/2018)
Genes from the TAS1R and TAS2R families of taste receptors: Looking for signatures of their adaptive role in human evolution
Taste perception is crucial in monitoring food intake and, hence, is thought to play a significant role in human evolution. To gain insights into possible adaptive signatures in genes encoding bitter, sweet, and umami taste receptors, we surveyed the available sequence variation data from the 1000 Genomes Project Phase 3 for TAS1R (TAS1R1-3) and TAS2R (TAS2R16 and TAS2R38) families. Our study demonstrated that genes from these two families have experienced contrasting evolutionary histories: While TAS1R1 and TAS1R3 showed worldwide evidence of positive selection, probably correlated with improved umami and sweet perception, the patterns of variation displayed by TAS2R16 and TAS2R38 were more consistent with scenarios of balancing selection that possibly conferred a heterozygous advantage associated with better capacity to perceive a wide range of bitter compounds. In TAS2R16, such adaptive events appear to have occurred restrictively in mainland Africa, whereas the strongest evidence in TAS2R38 was detected in Europe. Despite plausible associations between taste perception and the TAS1R and TAS2R selective signatures, we cannot discount other biological mechanisms as driving the evolutionary trajectories of those TAS1R and TAS2R members, especially given recent findings of taste receptors behaving as the products of pleiotropic genes involved in many functions outside the gustatory system.IPATIMUP is included in the i3S Consortium, which is partially supported by the Portuguese Foundation for Science and Technology (FCT). This work is also funded by FEDER funds through the Operational Programme Competitiveness Factors (COMPETE) and National Funds through the FCT (projects PEst-C/SAU/LA0003/2013 and POCI-01-0145-FEDER-007274, fellowships SFRH/BD/63343/2009 to C.V., SFRH/ BPD/65000/2009 to L.A., and SFRH/BPD/120777/2016 to P.I.M.), and by Programa Operacional Regional do Norte (Norte 2020), through FEDER funds under the Quadro de Referência Estratégico Nacional (QREN; NORTE-01-0145-FEDER-000029). We thank Jacquelyn Beals for the careful editing of the work. We also thank Sònia Casillas for the helpful instructions about the tracks from the PopHuman browser, and Miguel Arenas and Eduardo Conde Sousa for the aid in extracting data from those tracks
Essential genetic findings in neurodevelopmental disorders
Neurodevelopmental disorders (NDDs) represent a growing medical challenge in modern societies. Ever-increasing sophisticated diagnostic tools have been continuously revealing a remarkably complex architecture that embraces genetic mutations of distinct types (chromosomal rearrangements, copy number variants, small indels, and nucleotide substitutions) with distinct frequencies in the population (common, rare, de novo). Such a network of interacting players creates difficulties in establishing rigorous genotype-phenotype correlations. Furthermore, individual lifestyles may also contribute to the severity of the symptoms fueling a large spectrum of gene-environment interactions that have a key role on the relationships between genotypes and phenotypes.Herein, a review of the genetic discoveries related to NDDs is presented with the aim to provide useful general information for the medical community.This work was financed by FEDER - Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 - Operacional Programme for Competitiveness and Internationalization (POCI), Portugal 2020, and by Portuguese funds through FCT - Fundação para a Ciência e a Tecnologia, in the framework of the project POCI-01-0145-FEDER-007274 to i3S and UID/ BIM/04501/2013 and UID/BIM/04501/2019 to iBiMED, as well as by national funds (OE), through FCT, in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19 to RMS, and by FCT research project POCI-01-0145-FEDER-29723. ARC and CS hold FCT PhD fellowships (SFRH/BD/141702/2018-ARC and SFRH/BD/137925/2018-CS). Funders had no role in the design, collection, analysis, interpretation of the data, and writing of the manuscript
European Roma groups show complex West Eurasian admixture footprints and a common South Asian genetic origin
The Roma population is the largest transnational ethnic minority in Europe, characterized by a linguistic, cultural and historical heterogeneity. Comparative linguistics and genetic studies have placed the origin of European Roma in the Northwest of India. After their migration across Persia, they entered into the Balkan Peninsula, from where they spread into Europe, arriving in the Iberian Peninsula in the 15th century. Their particular demographic history has genetic implications linked to rare and common diseases. However, the South Asian source of the proto-Roma remains still untargeted and the West Eurasian Roma component has not been yet deeply characterized. Here, in order to describe both the South Asian and West Eurasian ancestries, we analyze previously published genome-wide data of 152 European Roma and 34 new Iberian Roma samples at a fine-scale and haplotype-based level, with special focus on the Iberian Roma genetic substructure. Our results suggest that the putative origin of the proto-Roma involves a Punjabi group with low levels of West Eurasian ancestry. In addition, we have identified a complex West Eurasian component (around 65%) in the Roma, as a result of the admixture events occurred with non-proto-Roma populations between 1270–1580. Particularly, we have detected the Balkan genetic footprint in all European Roma, and the Baltic and Iberian components in the Northern and Western Roma groups, respectively. Finally, our results show genetic substructure within the Iberian Roma, with different levels of West Eurasian admixture, as a result of the complex historical events occurred in the Peninsula.This work was supported by the Spanish Ministry of Economy and Competitiveness (grant number CGL2016-75389-P (MINEICO/FEDER, UE) and "Unidad María de Maeztu" (MDM-2014-0370) to DC and FC; and Agência de Gestió d'Ajuts Universitaris i de la Recerca (Generalitat de Catalunya, grant 2017SGR00702). NF-P was supported by a FPU17/03501 fellowship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Impact of a brief psychological intervention on lifestyle, risk factors and disease knowledge during phase I of cardiac rehabilitation after acute coronary syndrome
Introduction:This study examined the efficacy of a brief inpatient psychoeducational intervention on knowledge about acute coronary syndromes (ACS), control of risk factors, and adaptive health habits and lifestyle. The intervention was intended to facilitate rehabilitation after ACS and its short- and medium-term impact was assessed. Methods: One hundred and twenty-one patients with ACS, admitted to a central cardiology unit in Portugal, were randomized to an experimental group (EG, n=65) or a control group (CG, n=56). We used the Portuguese versions of the Knowledge Questionnaire and the Health Habits Questionnaire. Patients were assessed at hospital admission, hospital discharge and one- and two-month follow-up. Results: The intervention had a significant impact, increasing knowledge about ACS (F=500.834; p=0.000) in the EG, which was maintained at two-month follow-up, and changing health habits at two-month follow-up (F=218.129; p=0.000). The CG demonstrated decreased knowledge (F=3.368; p=0.069) during the same period. Conclusions: A brief inpatient psychoeducational intervention has a positive effect on knowledge about ACS, risk factor control and promotion of positive health habits, and is effective in improving cardiac rehabilitation
Exploring the effectiveness of the output-based aid voucher program to increase uptake of gender-based violence recovery services in Kenya: a qualitative evaluation
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Few studies in Africa have explored in detail the ability of output-based aid (OBA) voucher programs to increase access to gender-based violence recovery (GBVR) services. Methods: A qualitative study was conducted in 2010 and involved: (i) in-depth interviews (IDIs) with health managers, service providers, voucher management agency (VMA) managers and (ii) focus group discussions (FGDs) with voucher users, voucher non-users, voucher distributors and opinion leaders drawn from five program sites in Kenya. Results: The findings showed promising prospects for the uptake of OBA GBVR services among target population. However, a number of factors affect the uptake of the services. These include lack of general awareness of the GBVR services vouchers, lack of understanding of the benefit package, immediate financial needs of survivors, as well as stigma and cultural beliefs that undermine reporting of cases or seeking essential medical services. Moreover, accreditation of only hospitals to offer GBVR services undermines access to the services in rural areas. Poor responsiveness from law enforcement agencies and fear of reprisal from perpetrators also undermine treatment options and access to medical services. Low provider knowledge on GBVR services and lack of supplies also affect effective provision and management of GBVR services. Conclusions: The above findings suggest that there is a need to build the capacity of health care providers and police officers, strengthen the community strategy component of the OBA program to promote the GBVR services voucher, and conduct widespread community education programs aimed at prevention, ensuring survivors know how and where to access services and addressing stigma and cultural barriers.The Bill and Melinda Gates Foundatio
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