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1.
Sci Adv ; 10(14): eadl6595, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38569022

RESUMO

Mutually beneficial partnerships between genomics researchers and North American Indigenous Nations are rare yet becoming more common. Here, we present one such partnership that provides insight into the peopling of the Americas and furnishes another line of evidence that can be used to further treaty and Indigenous rights. We show that the genomics of sampled individuals from the Blackfoot Confederacy belong to a previously undescribed ancient lineage that diverged from other genomic lineages in the Americas in Late Pleistocene times. Using multiple complementary forms of knowledge, we provide a scenario for Blackfoot population history that fits with oral tradition and provides a plausible model for the evolutionary process of the peopling of the Americas.


Assuntos
Evolução Biológica , Genômica , Humanos , América , Genoma Humano
2.
Am J Trop Med Hyg ; 110(3): 417-420, 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38266289

RESUMO

Research capacity is a critical component of pandemic preparedness, as highlighted by the challenges faced during the Ebola outbreak in West Africa. Recent global initiatives, such as the Research & Development Task Force of the Global Health Security Agenda and the World Health Assembly's resolution on strengthening clinical trials, emphasize the need for robust research capabilities. This Perspective discusses the experiences of leaders in infectious disease research and capacity building in low- and middle-income countries, focusing on Colombia, Jamaica, and Pakistan. These case studies underscore the importance of collaborative efforts, interdisciplinary training, and global partnerships in pandemic response. The experiences highlight the necessity for rapid pathogen identification, capacity for genomic sequencing, and proactive engagement with policymakers. Challenges faced, including the shortage of trained staff and reliance on imported reagents, emphasize the ongoing need for building research capacity.


Assuntos
Doença pelo Vírus Ebola , Preparação para Pandemia , Humanos , Países em Desenvolvimento , Surtos de Doenças , Doença pelo Vírus Ebola/epidemiologia , Doença pelo Vírus Ebola/prevenção & controle , Saúde Global
3.
Trop Med Infect Dis ; 8(7)2023 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-37505666

RESUMO

Hepatitis C (HCV) continues to present a global public health challenge, with no vaccine available for prevention. Despite the availability of direct-acting antivirals (DAAs) to cure HCV, it remains prevalent in many regions including the Caribbean. As efforts are made to eliminate HCV from the region, existing barriers, such as the high cost of DAAs and lack of an established database of HCV cases within the Caribbean, must be addressed. This review seeks to assess epidemiologic trends (seroprevalence and genotypic diversity) of HCV in the Caribbean and identify gaps in surveillance of the disease. The literature for the period 1 January 2005 to October 2022 was reviewed to gather country-specific data on HCV across the Caribbean. References were identified through indexed journals accessed through established databases using the following keywords: Caribbean, genotype distribution, and general epidemiologic characteristics. The usage pattern of HCV drugs was determined from information obtained from pharmacists across the Caribbean including Jamaica. The prevalence of HCV in the Caribbean was 1.5%; the region should therefore be considered an area of moderate HCV prevalence. The prevalence of HCV among intravenous drug users (21.9-58.8%), persons living with HIV/AIDS (0.8 to 58.5%), prisoners (32.8-64%), and men who have sex with men (MSM) (0.8-6.9%) was generally higher than in the general population (0.8-2.3%). Genotype 1 (83%) was most prevalent followed by genotypes 2 (7.2%) and 3 (2.1%), respectively. Less than 50% of countries in the Caribbean have reliable or well-curated surveillance data on HCV. Drugs currently being used for treatment of HCV infections across the Caribbean include Epclusa (sofosbuvir/velpatasvir) and Harvoni (ledipasvir/sofosbuvir). Some of these drugs are only available in the private sector and are sourced externally whenever needed. While trends point to a potentially higher prevalence of HCV, it will require well-designed random surveys to obtain better estimates of the infection seroprevalence, supported by strong public health laboratory systems. DAAs that are pan-genotypic should translate into treatments that are affordable, accessible, and available to improve cure rates and reduce the HCV burden in the population.

4.
Evol Anthropol ; 32(4): 195-205, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37450551

RESUMO

The evolution of skin pigmentation has been shaped by numerous biological and cultural shifts throughout human history. Vitamin D is considered a driver of depigmentation evolution in humans, given the deleterious health effects associated with vitamin D deficiency, which is often shaped by cultural factors. New advancements in genomics and epigenomics have opened the door to a deeper exploration of skin pigmentation evolution in both contemporary and ancient populations. Data from ancient Europeans has offered great context to the spread of depigmentation alleles via the evaluation of migration events and cultural shifts that occurred during the Neolithic. However, novel insights can further be gained via the inclusion of diverse ancient and contemporary populations. Here we present on how potential biases and limitations in skin pigmentation research can be overcome with the integration of interdisciplinary data that includes both cultural and biological elements, which have shaped the evolutionary history of skin pigmentation in humans.


Assuntos
Hominidae , Pigmentação da Pele , Animais , Humanos , Evolução Biológica , Genômica
5.
Ann Glob Health ; 89(1): 38, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37273490

RESUMO

Background: The ESSENCE on Health Research initiative established a Working Group on Review of Investments in 2018 to improve coordination and collaboration among funders of health research capacity strengthening. The Working Group comprises more than a dozen ESSENCE members, including diverse representation by geography, country income level, the public sector, and philanthropy. Objective: The overall goal of the Working Group is increased research on national health priorities as well as improved pandemic preparedness, and, ultimately, fewer countries with very limited research capacity. Methods: We developed a basic set of metrics for national health research capacity, assessed different models of coordination and collaboration, took a deeper dive into eight countries to characterize their national research capacity, and began to identify opportunities to better coordinate our investments. In this article, we summarize the presentations, discussions, and outcomes of our second annual (virtual) meeting, which had more than 100 participants representing funders, researchers, and other stakeholders from higher- and lower-income countries worldwide. Findings and conclusions: Presentations on the first day included the keynote speaker, Dr. Soumya Swaminathan, chief scientist of the World Health Organization (WHO), and updates on data and metrics for research capacity, which are critical to establish targets, road maps, and budgets. The second day focused on improving collaboration and coordination among funders and other stakeholders, the potential return on investment for health research, ongoing work to increase coordination at the country level, and examples of research capacity strengthening efforts in diverse health research areas from around the world. We concluded that an intentional data- and metric-driven approach to health research capacity strengthening, emphasizing coordination among funders, local leadership, and equitable partnerships and allocation of resources, will enhance the health systems of resource-poor countries as well as the world's pandemic preparedness.


Assuntos
Benchmarking , Prioridades em Saúde , Humanos , Fortalecimento Institucional
6.
Curr Biol ; 33(8): 1573-1581.e5, 2023 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-36931272

RESUMO

Despite its crucial location, the western side of Amazonia between the Andes and the source(s) of the Amazon River is still understudied from a genomic and archaeogenomic point of view, albeit possibly harboring essential information to clarify the complex genetic history of local Indigenous groups and their interactions with nearby regions,1,2,3,4,5,6,7,8 including central America and the Caribbean.9,10,11,12 Focusing on this key region, we analyzed the genome-wide profiles of 51 Ashaninka individuals from Amazonian Peru, observing an unexpected extent of genomic variation. We identified at least two Ashaninka subgroups with distinctive genomic makeups, which were differentially shaped by the degree and timing of external admixtures, especially with the Indigenous groups from the Andes and the Pacific coast. On a continental scale, Ashaninka ancestors probably derived from a south-north migration of Indigenous groups moving into the Amazonian rainforest from a southeastern area with contributions from the Southern Cone and the Atlantic coast. These ancestral populations diversified in the variegated geographic regions of interior South America, on the eastern side of the Andes, differentially interacting with surrounding coastal groups. In this complex scenario, we also revealed strict connections between the ancestors of present-day Ashaninka, who belong to the Arawakan language family,13 and those Indigenous groups that moved further north into the Caribbean, contributing to the early Ceramic (Saladoid) tradition in the islands.14,15.


Assuntos
Etnicidade , Genética Populacional , Humanos , Peru , América do Sul , Etnicidade/genética , Genômica
7.
iScience ; 26(2): 106034, 2023 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-36824277

RESUMO

Most studies focusing on human high-altitude adaptation in the Andean highlands have thus far been focused on Peruvian populations. We present high-coverage whole genomes from Indigenous people living in the Ecuadorian highlands and perform multi-method scans to detect positive natural selection. We identified regions of the genome that show signals of strong selection to both cardiovascular and hypoxia pathways, which are distinct from those uncovered in Peruvian populations. However, the strongest signals of selection were related to regions of the genome that are involved in immune function related to tuberculosis. Given our estimated timing of this selection event, the Indigenous people of Ecuador may have adapted to Mycobacterium tuberculosis thousands of years before the arrival of Europeans. Furthermore, we detect a population collapse that coincides with the arrival of Europeans, which is more severe than other regions of the Andes, suggesting differing effects of contact across high-altitude populations.

8.
Proc Biol Sci ; 289(1986): 20221078, 2022 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-36322514

RESUMO

An increasing body of archaeological and genomic evidence has hinted at a complex settlement process of the Americas by humans. This is especially true for South America, where unexpected ancestral signals have raised perplexing scenarios for the early migrations into different regions of the continent. Here, we present ancient human genomes from the archaeologically rich Northeast Brazil and compare them to ancient and present-day genomic data. We find a distinct relationship between ancient genomes from Northeast Brazil, Lagoa Santa, Uruguay and Panama, representing evidence for ancient migration routes along South America's Atlantic coast. To further add to the existing complexity, we also detect greater Denisovan than Neanderthal ancestry in ancient Uruguay and Panama individuals. Moreover, we find a strong Australasian signal in an ancient genome from Panama. This work sheds light on the deep demographic history of eastern South America and presents a starting point for future fine-scale investigations on the regional level.


Assuntos
Migração Humana , Homem de Neandertal , Humanos , História Antiga , Animais , Genômica , Genoma Humano , Brasil
9.
J Clin Virol Plus ; 2(4): 100124, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36415687

RESUMO

A cross-sectional SARS-CoV-2 serosurvey was conducted after the Omicron surge in Jamaica using 1,540 samples collected during March - May 2022 from persons attending antenatal, STI and non-communicable diseases clinics in Kingston, Jamaica. SARS-CoV-2 spike receptor binding domain (RBD) and/or nucleocapsid IgG antibodies were detected for 88.4% of the study population, with 77.0% showing evidence of previous SARS-CoV-2 infection. Of persons previously infected with SARS-CoV-2 and/or with COVID-19 vaccination, 9.6% were negative for spike RBD IgG, most of which were unvaccinated previously infected persons. Amongst unvaccinated previously infected people, age was associated with testing spike RBD IgG negative. When considering all samples, median spike RBD IgG levels were 131.6 BAU/mL for unvaccinated persons with serological evidence of past infection, 90.3 BAU/mL for vaccinated persons without serological evidence of past infection, and 896.1 BAU/mL for vaccinated persons with serological evidence of past infection. Our study of the first reported SARS-CoV-2 serosurvey in Jamaica shows extensive SARS-CoV-2 population immunity, identifies a substantial portion of the population lacking spike RBD IgG, and provides additional evidence for increasing COVID-19 vaccine coverage in Jamaica.

10.
medRxiv ; 2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36172133

RESUMO

A cross-sectional SARS-CoV-2 serosurvey was conducted after the Omicron surge in Jamaica using 1,540 samples collected during March â€" May 2022 from persons attending antenatal, STI and non-communicable diseases clinics in Kingston, Jamaica. SARS-CoV-2 spike receptor binding domain (RBD) and/or nucleocapsid IgG antibodies were detected for 88.4% of the study population, with 77.0% showing evidence of previous SARS-CoV-2 infection. Of persons previously infected with SARS-CoV-2 and/or with COVID-19 vaccination, 9.6% were negative for spike RBD IgG, most of which were unvaccinated previously infected persons. Amongst unvaccinated previously infected people, age was associated with testing spike RBD IgG negative. When considering all samples, median spike RBD IgG levels were 131.6 BAU/mL for unvaccinated persons with serological evidence of past infection, 90.3 BAU/mL for vaccinated persons without serological evidence of past infection, and 896.1 BAU/mL for vaccinated persons with serological evidence of past infection. Our study of the first reported SARS-CoV-2 serosurvey in Jamaica shows extensive SARS-CoV-2 population immunity, identifies a substantial portion of the population lacking spike RBD IgG, and provides additional evidence for increasing COVID-19 vaccine coverage in Jamaica.

11.
Int J Infect Dis ; 117: 356-360, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35134559

RESUMO

Detection and epidemiologic characterization of infectious disease outbreaks are key for early identification and response to potential pandemic threats. The rapid global spread of severe SARS-CoV-2 in 2020 highlighted the critical role of diagnostics in understanding the epidemiology of the virus early in the pandemic. As a natural extension of Abbott's work in diagnostics, virus discovery, and virus surveillance, the Abbott Pandemic Defense Coalition (APDC) was launched in early 2021. The APDC is a global multisector scientific and public health partnership whose primary objective is the early detection and mitigation of infectious disease threats of pandemic potential. As of January 2022, the APDC network has partners on 5 continents including academic institutions, governmental, and nongovernmental organizations. A novel element of the APDC is the capacity for early development and rapid deployment of scalable, quality diagnostics targeting newly identified pathogens of pandemic potential.


Assuntos
COVID-19 , Pandemias , COVID-19/epidemiologia , COVID-19/prevenção & controle , Surtos de Doenças , Humanos , Pandemias/prevenção & controle , Saúde Pública , SARS-CoV-2
12.
Genes Brain Behav ; 21(3): e12783, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35044077

RESUMO

The gene-culture coevolution (GCC) framework has gained increasing prominence in the social and biological sciences. While most studies on human GCC concern the evolution of low-level physiological traits, attempts have also been made to apply GCC to complex human traits, including social behavior and cognition. One major methodological challenge in this endeavor is to reconstruct a specific biological pathway between the implicated genes and their distal phenotypes. Here, we introduce a novel approach that combines data on population genetics and expression quantitative trait loci to infer the specific intermediate phenotypes of genes in the brain. We suggest that such "neuroendophenotypes" will provide more detailed mechanistic insights into the GCC process. We present a case study where we explored a GCC dynamics between the oxytocin receptor gene (OXTR) and cultural tightness-looseness. By combining data from the 1000 Genomes project and the Gene-Tissue-Expression project (GTEx), we estimated and compared OXTR expression in 10 brain regions across five human superpopulations. We found that OXTR expression in the anterior cingulate cortex (ACC) was highly variable across populations, and this variation correlated with cultural tightness and socio-ecological threats worldwide. The mediation models also suggested possible GCC dynamics where the increased OXTR expression in the ACC mediates or emerges from the tight culture and higher socio-ecological threats. Formal selection scans further confirmed that OXTR alleles linked to enhanced receptor expression in the ACC underwent positive selection in East Asian countries with tighter social norms. We discuss the implications of our method in human GCC research.


Assuntos
Ocitocina , Receptores de Ocitocina , Alelos , Encéfalo/metabolismo , Humanos , Ocitocina/genética , Ocitocina/metabolismo , Receptores de Ocitocina/genética , Receptores de Ocitocina/metabolismo , Comportamento Social
13.
PNAS Nexus ; 1(2): pgac047, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-36713318

RESUMO

The prehistory of the people of Uruguay is greatly complicated by the dramatic and severe effects of European contact, as with most of the Americas. After the series of military campaigns that exterminated the last remnants of nomadic peoples, Uruguayan official history masked and diluted the former Indigenous ethnic diversity into the narrative of a singular people that all but died out. Here, we present the first whole genome sequences of the Indigenous people of the region before the arrival of Europeans, from an archaeological site in eastern Uruguay that dates from 2,000 years before present. We find a surprising connection to ancient individuals from Panama and eastern Brazil, but not to modern Amazonians. This result may be indicative of a migration route into South America that may have occurred along the Atlantic coast. We also find a distinct ancestry previously undetected in South America. Though this work begins to piece together some of the demographic nuance of the region, the sequencing of ancient individuals from across Uruguay is needed to better understand the ancient prehistory and genetic diversity that existed before European contact, thereby helping to rebuild the history of the Indigenous population of what is now Uruguay.

14.
Genes (Basel) ; 12(3)2021 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-33801556

RESUMO

The South American continent is remarkably diverse in its ecological zones, spanning the Amazon rainforest, the high-altitude Andes, and Tierra del Fuego. Yet the original human populations of the continent successfully inhabited all these zones, well before the buffering effects of modern technology. Therefore, it is likely that the various cultures were successful, in part, due to positive natural selection that allowed them to successfully establish populations for thousands of years. Detecting positive selection in these populations is still in its infancy, as the ongoing effects of European contact have decimated many of these populations and introduced gene flow from outside of the continent. In this review, we explore hypotheses of possible human biological adaptation, methods to identify positive selection, the utilization of ancient DNA, and the integration of modern genomes through the identification of genomic tracts that reflect the ancestry of the first populations of the Americas.


Assuntos
Adaptação Biológica , DNA Antigo/análise , Genômica/métodos , Evolução Molecular , Fluxo Gênico , Genética Populacional , Humanos , Seleção Genética , América do Sul/etnologia
15.
Genes Brain Behav ; 20(3): e12715, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33200560

RESUMO

Chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) diverged into distinct species approximately 1.7 million years ago when the ancestors of modern-day bonobo populations were separated by the Congo River. This geographic boundary separates the two species today and the associated ecological factors, including resource distribution and feeding competition, have likely shaped the divergent social behavior of both species. The most striking behavioral differences pertain to between group interactions in which chimpanzees behave aggressively towards unfamiliar conspecifics, while bonobos display remarkable tolerance. Several hypotheses attempt to explain how different patterns of social behavior have come to exist in the two species, some with specific genetic predictions, likening the evolution of bonobos to a process of domestication. Here, we utilize 73 ape genomes and apply linkage haplotype homozygosity and structure informed allele frequency differentiation methods to identify positively selected regions in bonobos since their split from a common pan ancestor to better understand the environment and processes that resulted in the behavioral differences observed today. We find novel evidence of selection in genetic regions that aid in starch digestion (AMY2) along with support for two genetic predictions related to self-domestication processes hypothesized to have occurred in the bonobo. We also find evidence for selection on neuroendocrine pathways associated with social behavior including the oxytocin, serotonin, and gonadotropin releasing hormone pathways.


Assuntos
Dieta , Pan paniscus/genética , Pan troglodytes/genética , Polimorfismo Genético , Seleção Genética , Comportamento Social , Animais , Evolução Molecular , Frequência do Gene , Haplótipos , Ocitocina/genética , Pan paniscus/fisiologia , Pan troglodytes/fisiologia , alfa-Amilases Pancreáticas/genética , Serotonina/genética
16.
Exp Parasitol ; 198: 26-30, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30710500

RESUMO

Extracting genomic DNA of pathogenic agents from formalin-fixed specimens is inherently difficult. Storage of samples in formalin results in nucleic acid cross-linking and DNA fragmentation. In this study, DNA was extracted from 45 Giardia-positive stool samples stored in formalin and subjected to PCR amplification targeting the triose phosphate isomerase (tpi), beta gardin (bg) and glutamate dehydrogenase (gdh) genes. Samples were rehydrated by using a descending alcohol series before DNA extraction using a commercial kit. This was followed by EDTA-mediated inhibition of DNase activity and prolonged treatment with proteinase K to digest contaminating proteins. DNA was amplified at rates of 64.4% (29/45) at the tpi, 40% (18/45) at the bg and 20% (9/45) at the gdh loci as seen on nested PCR. DNA quality was subsequently tested in a genotyping experiment which produced high-quality sequences at the tpi (41.2%; 12/29) bg (50%; 9/18), and gdh (22.2%; 2/9) loci and enabled differentiation of Giardia strains at the subtype level. The modified extraction protocol was effective at removing inhibitors and reversing cross-linking of DNA. However, PCR amplification was limited to short fragments of DNA which resulted in highest success rate on amplification of the shortest (334 bp) gene fragment tested.


Assuntos
DNA de Protozoário/isolamento & purificação , Fezes/parasitologia , Fixadores/efeitos adversos , Formaldeído/efeitos adversos , Giardia/genética , Sequência de Bases , Proteínas do Citoesqueleto/genética , DNA de Protozoário/química , DNA de Protozoário/genética , DNA de Protozoário/normas , Etanol/administração & dosagem , Genótipo , Técnicas de Genotipagem , Giardia/química , Giardia/classificação , Giardia/enzimologia , Glutamato Desidrogenase/genética , Humanos , Reação em Cadeia da Polimerase , Proteínas de Protozoários/genética , Solventes/administração & dosagem , Fatores de Tempo , Triose-Fosfato Isomerase/genética
17.
J Investig Clin Dent ; 10(1): e12365, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30338674

RESUMO

AIM: Human papillomavirus (HPV) has been reported to be associated with oral and oropharyngeal cancer. However, little information is available about the epidemiology of oral HPV infection in Jamaica. The purpose of the present study was to assess the prevalence of oral HPV strains using the oral rinse method in HIV and non-HIV Jamaican patients, as well as to determine the association of HPV with sexual practices, smoking, and alcohol use. METHODS: A cross-sectional study was conducted on patients attending The University of the West Indies Mona Dental Polyclinic and the Centre for HIV/AIDS Research and Education Services. Salivary samples were tested through molecular analysis for 37 HPV genotypes using the linear array HPV genotyping test. A survey questionnaire was used to obtain demographic details, smoking history, alcohol practice, sexual practice, and history of HPV testing. RESULTS: The HPV prevalence was 8.65% in 18-64 y olds (N = 104), with a slight female predilection (55%). No high-risk HPV types were found. HPV-84 was the most common type in both HIV and non-HIV patients; 66.7% of HPV-positive participants reported that they had six or more lifetime sexual partners. CONCLUSION: The prevalence of oral HPV was similar to that in other countries. No statistically-significant relationship was observed between the prevalence of HPV and either the number of sexual partners, smoking, or alcohol history. A nationwide study on oral HPV detection might be helpful in developing a HPV vaccination policy in Jamaica.


Assuntos
Genótipo , Infecções por HIV/complicações , Epidemiologia Molecular , Antissépticos Bucais , Papillomaviridae/genética , Infecções por Papillomavirus/complicações , Adolescente , Adulto , Estudos Transversais , DNA Viral/análise , Feminino , Técnicas de Genotipagem , Humanos , Jamaica/epidemiologia , Masculino , Pessoa de Meia-Idade , Doenças da Boca/epidemiologia , Doenças da Boca/virologia , Neoplasias Orofaríngeas , Prevalência , Fatores de Risco , Comportamento Sexual , Fumar , Inquéritos e Questionários , Adulto Jovem
18.
Sci Adv ; 4(11): eaau4921, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30417096

RESUMO

The peopling of the Andean highlands above 2500 m in elevation was a complex process that included cultural, biological, and genetic adaptations. Here, we present a time series of ancient whole genomes from the Andes of Peru, dating back to 7000 calendar years before the present (BP), and compare them to 42 new genome-wide genetic variation datasets from both highland and lowland populations. We infer three significant features: a split between low- and high-elevation populations that occurred between 9200 and 8200 BP; a population collapse after European contact that is significantly more severe in South American lowlanders than in highland populations; and evidence for positive selection at genetic loci related to starch digestion and plausibly pathogen resistance after European contact. We do not find selective sweep signals related to known components of the human hypoxia response, which may suggest more complex modes of genetic adaptation to high altitude.


Assuntos
Adaptação Fisiológica/genética , DNA Antigo/análise , Genética Populacional , Genoma Humano , Hipóxia/genética , Indígenas Sul-Americanos/genética , Polimorfismo de Nucleotídeo Único , Genótipo , Humanos , Dinâmica Populacional , Análise de Sequência de DNA , Sequenciamento Completo do Genoma
19.
Science ; 360(6392): 1024-1027, 2018 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-29853687

RESUMO

Little is known regarding the first people to enter the Americas and their genetic legacy. Genomic analysis of the oldest human remains from the Americas showed a direct relationship between a Clovis-related ancestral population and all modern Central and South Americans as well as a deep split separating them from North Americans in Canada. We present 91 ancient human genomes from California and Southwestern Ontario and demonstrate the existence of two distinct ancestries in North America, which possibly split south of the ice sheets. A contribution from both of these ancestral populations is found in all modern Central and South Americans. The proportions of these two ancestries in ancient and modern populations are consistent with a coastal dispersal and multiple admixture events.


Assuntos
Evolução Biológica , Emigração e Imigração , Genoma Humano , População/genética , California , Humanos , Ontário
20.
Am J Hum Genet ; 102(5): 806-815, 2018 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-29706345

RESUMO

The effects of European colonization on the genomes of Native Americans may have produced excesses of potentially deleterious features, mainly due to the severe reductions in population size and corresponding losses of genetic diversity. This assumption, however, neither considers actual genomic patterns that existed before colonization nor does it adequately capture the effects of admixture. In this study, we analyze the whole-exome sequences of modern and ancient individuals from a Northwest Coast First Nation, with a demographic history similar to other indigenous populations from the Americas. We show that in approximately ten generations from initial European contact, the modern individuals exhibit reduced levels of novel and low-frequency variants, a lower proportion of potentially deleterious alleles, and decreased heterozygosity when compared to their ancestors. This pattern can be explained by a dramatic population decline, resulting in the loss of potentially damaging low-frequency variants, and subsequent admixture. We also find evidence that the indigenous population was on a steady decline in effective population size for several thousand years before contact, which emphasizes regional demography over the common conception of a uniform expansion after entry into the Americas. This study examines the genomic consequences of colonialism on an indigenous group and describes the continuing role of gene flow among modern populations.


Assuntos
Variação Genética , Indígenas Norte-Americanos/genética , População Branca/genética , Pareamento de Bases/genética , Frequência do Gene/genética , Pool Gênico , Heterozigoto , Humanos , Polimorfismo de Nucleotídeo Único/genética , Fatores de Tempo
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