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1.
Cell ; 184(12): 3256-3266.e13, 2021 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-34048699

RESUMO

Northern East Asia was inhabited by modern humans as early as 40 thousand years ago (ka), as demonstrated by the Tianyuan individual. Using genome-wide data obtained from 25 individuals dated to 33.6-3.4 ka from the Amur region, we show that Tianyuan-related ancestry was widespread in northern East Asia before the Last Glacial Maximum (LGM). At the close of the LGM stadial, the earliest northern East Asian appeared in the Amur region, and this population is basal to ancient northern East Asians. Human populations in the Amur region have maintained genetic continuity from 14 ka, and these early inhabitants represent the closest East Asian source known for Ancient Paleo-Siberians. We also observed that EDAR V370A was likely to have been elevated to high frequency after the LGM, suggesting the possible timing for its selection. This study provides a deep look into the population dynamics of northern East Asia.


Assuntos
Dinâmica Populacional , DNA Antigo/análise , Ásia Oriental , Feminino , Variação Genética , Genética Populacional , Genoma Humano , Geografia , Humanos , Camada de Gelo , Funções Verossimilhança , Masculino , Modelos Genéticos , Filogenia , Análise de Componente Principal , Fatores de Tempo
2.
Cell ; 184(18): 4612-4625.e14, 2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-34352227

RESUMO

The Middle East region is important to understand human evolution and migrations but is underrepresented in genomic studies. Here, we generated 137 high-coverage physically phased genome sequences from eight Middle Eastern populations using linked-read sequencing. We found no genetic traces of early expansions out-of-Africa in present-day populations but found Arabians have elevated Basal Eurasian ancestry that dilutes their Neanderthal ancestry. Population sizes within the region started diverging 15-20 kya, when Levantines expanded while Arabians maintained smaller populations that derived ancestry from local hunter-gatherers. Arabians suffered a population bottleneck around the aridification of Arabia 6 kya, while Levantines had a distinct bottleneck overlapping the 4.2 kya aridification event. We found an association between movement and admixture of populations in the region and the spread of Semitic languages. Finally, we identify variants that show evidence of selection, including polygenic selection. Our results provide detailed insights into the genomic and selective histories of the Middle East.


Assuntos
Genética Populacional/história , Genoma Humano , Animais , Cromossomos Humanos Y/genética , Bases de Dados Genéticas , Pool Gênico , Introgressão Genética , Geografia , História Antiga , Migração Humana , Humanos , Oriente Médio , Modelos Genéticos , Homem de Neandertal/genética , Filogenia , Densidade Demográfica , Seleção Genética , Análise de Sequência de DNA
3.
Cell ; 184(1): 76-91.e13, 2021 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-33147444

RESUMO

Identification of host genes essential for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may reveal novel therapeutic targets and inform our understanding of coronavirus disease 2019 (COVID-19) pathogenesis. Here we performed genome-wide CRISPR screens in Vero-E6 cells with SARS-CoV-2, Middle East respiratory syndrome CoV (MERS-CoV), bat CoV HKU5 expressing the SARS-CoV-1 spike, and vesicular stomatitis virus (VSV) expressing the SARS-CoV-2 spike. We identified known SARS-CoV-2 host factors, including the receptor ACE2 and protease Cathepsin L. We additionally discovered pro-viral genes and pathways, including HMGB1 and the SWI/SNF chromatin remodeling complex, that are SARS lineage and pan-coronavirus specific, respectively. We show that HMGB1 regulates ACE2 expression and is critical for entry of SARS-CoV-2, SARS-CoV-1, and NL63. We also show that small-molecule antagonists of identified gene products inhibited SARS-CoV-2 infection in monkey and human cells, demonstrating the conserved role of these genetic hits across species. This identifies potential therapeutic targets for SARS-CoV-2 and reveals SARS lineage-specific and pan-CoV host factors that regulate susceptibility to highly pathogenic CoVs.


Assuntos
Infecções por Coronavirus/genética , Estudo de Associação Genômica Ampla , Interações Hospedeiro-Patógeno , SARS-CoV-2/fisiologia , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , COVID-19/imunologia , COVID-19/virologia , Linhagem Celular , Chlorocebus aethiops , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Coronavirus/classificação , Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/imunologia , Técnicas de Inativação de Genes , Redes Reguladoras de Genes , Células HEK293 , Proteína HMGB1/genética , Proteína HMGB1/metabolismo , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Humanos , Células Vero , Internalização do Vírus
4.
Cell ; 181(5): 1158-1175.e28, 2020 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-32470401

RESUMO

Here, we report genome-wide data analyses from 110 ancient Near Eastern individuals spanning the Late Neolithic to Late Bronze Age, a period characterized by intense interregional interactions for the Near East. We find that 6th millennium BCE populations of North/Central Anatolia and the Southern Caucasus shared mixed ancestry on a genetic cline that formed during the Neolithic between Western Anatolia and regions in today's Southern Caucasus/Zagros. During the Late Chalcolithic and/or the Early Bronze Age, more than half of the Northern Levantine gene pool was replaced, while in the rest of Anatolia and the Southern Caucasus, we document genetic continuity with only transient gene flow. Additionally, we reveal a genetically distinct individual within the Late Bronze Age Northern Levant. Overall, our study uncovers multiple scales of population dynamics through time, from extensive admixture during the Neolithic period to long-distance mobility within the globalized societies of the Late Bronze Age. VIDEO ABSTRACT.


Assuntos
DNA Antigo/análise , Etnicidade/genética , Fluxo Gênico/genética , Arqueologia/métodos , DNA Mitocondrial/genética , Etnicidade/história , Fluxo Gênico/fisiologia , Variação Genética/genética , Genética Populacional/métodos , Genoma Humano/genética , Genômica/métodos , Haplótipos , História Antiga , Migração Humana/história , Humanos , Região do Mediterrâneo , Oriente Médio , Análise de Sequência de DNA
5.
Semin Immunol ; 67: 101763, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37075586

RESUMO

Consanguineous marriages in Middle Eastern and North African (MENA) countries are deeply-rooted tradition and highly prevalent resulting into increased prevalence of autosomal recessive diseases including Inborn Errors of Immunity (IEIs). Molecular genetic testing is an important diagnostic tool for IEIs since it provides a definite diagnosis, genotype-phenotype correlation, and guide therapy. In this review, we will discuss the current state and challenges of genomic and variome studies in MENA region populations, as well as the importance of funding advanced genome projects. In addition, we will review the MENA underlying molecular genetic defects of over 2457 patients published with the common IEIs, where autosomal recessive mode of inheritance accounts for 76% of cases with increased prevalence of combined immunodeficiency diseases (50%). The efforts made in the last three decades in terms of international collaboration and of in situ capacity building in MENA region countries led to the discovery of more than 150 novel genes involved in IEIs. Expanding sequencing studies within the MENA will undoubtedly be a unique asset for the IEI genetics which can advance research, and support precise genomic diagnostics and therapeutics.


Assuntos
Consanguinidade , Doenças do Sistema Imunitário , População do Oriente Médio , População do Norte da África , Humanos , África do Norte/epidemiologia , População do Norte da África/genética , População do Oriente Médio/genética , Doenças do Sistema Imunitário/genética
6.
Proc Natl Acad Sci U S A ; 121(38): e2403655121, 2024 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-39250671

RESUMO

The presence of livestock inside protected areas, or "livestock encroachment," is a global conservation concern because livestock is broadly thought to negatively affect wildlife. The Maasai Mara National Reserve (MMNR), Kenya, exemplifies this tension as livestock is believed to have resulted in the declining wildlife populations, contributing to the strict and sometimes violent exclusion measures targeting Maasai pastoralists. However, research embedded in the real-world setting that draws insights from the social-ecological contexts is lacking. In this study, we conducted 19 mo of ecological monitoring covering 60 sites in MMNR and found that cattle presence inside the reserve did not significantly impact most co-occurring wild herbivores at the current intensity. Using the Hierarchical Modeling of Species Communities and Gaussian copula graphic models, we showed that cattle had no direct associations-neither negative nor positive-with nearly all wild herbivores despite frequently sharing the same space. Moreover, we did not detect resource degradation correlated with cattle presence near the MMNR boundary. Given the colonial legacy and land use history of Mara, entering MMNR becomes the only viable option for many herders. These results corroborate the emerging perspective that the ecological impacts of extensively herded livestock on wildlife might be more nuanced than previously thought. To effectively balance the needs of people, livestock, and wildlife, the current rigid livestock exclusion measures need to be reassessed to holistically consider herbivore ecology, local land use history, and modern politics of protected area management.


Assuntos
Conservação dos Recursos Naturais , Gado , Animais , Quênia , Bovinos , Herbivoria , Ecossistema , Animais Selvagens
7.
Proc Natl Acad Sci U S A ; 121(11): e2313123121, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38437546

RESUMO

Organized flaking techniques to obtain predetermined stone tools have been traced back to the early Acheulean (also known as mode 2) in Africa and are seen as indicative of the emergence of advanced technical abilities and in-depth planning skills among early humans. Here, we report one of the earliest known examples of prepared core technology in the archaeological record, at the Cenjiawan (CJW) site in the Nihewan basin of China, dated 1.1 Mya. The operational schemes reconstructed from the CJW refit sets, together with shaping patterns observed in the retouched tools, suggest that Nihewan basin toolmakers had the technical abilities of mode 2 hominins, and developed different survival strategies to adapt to local raw materials and environments. This finding predates the previously earliest known prepared core technology from Eurasia by 0.3 My, and the earliest known mode 2 sites in East Asia by a similar amount of time, thus suggesting that hominins with advanced technologies may have migrated into high latitude East Asia as early as 1.1 Mya.


Assuntos
Hominidae , Tecnologia , Humanos , Animais , Ásia Oriental , China , África
8.
Proc Natl Acad Sci U S A ; 120(2): e2211055120, 2023 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-36595676

RESUMO

Endemic Burkitt lymphoma (eBL) is a pediatric cancer coendemic with malaria in sub-Saharan Africa, suggesting an etiological link between them. However, previous cross-sectional studies of limited geographic areas have not found a convincing association. We used spatially detailed data from the Epidemiology of Burkitt Lymphoma in East African Children and Minors (EMBLEM) study to assess this relationship. EMBLEM is a case-control study of eBL from 2010 through 2016 in six regions of Kenya, Uganda, and Tanzania. To measure the intensity of exposure to the malaria parasite, Plasmodium falciparum, among children in these regions, we used high-resolution spatial data from the Malaria Atlas Project to estimate the annual number of P. falciparum infections from 2000 through 2016 for each of 49 districts within the study region. Cumulative P. falciparum exposure, calculated as the sum of annual infections by birth cohort, varied widely, with a median of 47 estimated infections per child by age 10, ranging from 4 to 315 infections. eBL incidence increased 39% for each 100 additional lifetime P. falciparum infections (95% CI: 6.10 to 81.04%) with the risk peaking among children aged 5 to 11 and declining thereafter. Alternative models using estimated annual P. falciparum infections 0 to 10 y before eBL onset were inconclusive, suggesting that eBL risk is a function of cumulative rather than recent cross-sectional exposure. Our findings provide population-level evidence that eBL is a phenotype related to heavy lifetime exposure to P. falciparum malaria and support emphasizing the link between malaria and eBL.


Assuntos
Linfoma de Burkitt , Malária Falciparum , Malária , Humanos , Linfoma de Burkitt/epidemiologia , Linfoma de Burkitt/genética , Plasmodium falciparum , Estudos de Casos e Controles , Uganda/epidemiologia , Quênia/epidemiologia , Tanzânia/epidemiologia , Estudos Transversais , Malária Falciparum/complicações , Malária Falciparum/epidemiologia , Malária Falciparum/parasitologia , Malária/epidemiologia
9.
Proc Natl Acad Sci U S A ; 120(4): e2210611120, 2023 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-36649412

RESUMO

Growing reliance on animal and plant domestication in the Near East and beyond during the Pre-Pottery Neolithic B (PPNB) (the ninth to eighth millennium BC) has often been associated with a "revolutionary" social transformation from mobility toward more sedentary lifestyles. We are able to yield nuanced insights into the process of the Neolithization in the Near East based on a bioarchaeological approach integrating isotopic and archaeogenetic analyses on the bone remains recovered from Nevali Çori, a site occupied from the early PPNB in Turkey where some of the earliest evidence of animal and plant domestication emerged, and from Ba'ja, a typical late PPNB site in Jordan. In addition, we present the archaeological sequence of Nevali Çori together with newly generated radiocarbon dates. Our results are based on strontium (87Sr/86Sr), carbon, and oxygen (δ18O and δ13Ccarb) isotopic analyses conducted on 28 human and 29 animal individuals from the site of Nevali Çori. 87Sr/86Sr results indicate mobility and connection with the contemporaneous surrounding sites during the earlier PPNB prior to an apparent decline in this mobility at a time of growing reliance on domesticates. Genome-wide data from six human individuals from Nevali Çori and Ba'ja demonstrate a diverse gene pool at Nevali Çori that supports connectedness within the Fertile Crescent during the earlier phases of Neolithization and evidence of consanguineous union in the PPNB Ba'ja and the Iron Age Nevali Çori.


Assuntos
Carbono , Domesticação , Animais , Humanos , História Antiga , Turquia , Jordânia , Arqueologia , DNA
10.
Mol Biol Evol ; 41(7)2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-39011558

RESUMO

Immunoglobulins (Igs) have a crucial role in humoral immunity. Two recent studies have reported a high-frequency Neanderthal-introgressed haplotype throughout Eurasia and a high-frequency Neanderthal-introgressed haplotype specific to southern East Asia at the immunoglobulin heavy-chain (IGH) gene locus on chromosome 14q32.33. Surprisingly, we found the previously reported high-frequency Neanderthal-introgressed haplotype does not exist throughout Eurasia. Instead, our study identified two distinct high-frequency haplotypes of putative Neanderthal origin in East Asia and Europe, although they shared introgressed alleles. Notably, the alleles of putative Neanderthal origin reduced the expression of IGHG1 and increased the expression of IGHG2 and IGHG3 in various tissues. These putatively introgressed alleles also affected the production of IgG1 upon antigen stimulation and increased the risk of systemic lupus erythematosus. Additionally, the greatest genetic differentiation across the whole genome between southern and northern East Asians was observed for the East Asian haplotype of putative Neanderthal origin. The frequency decreased from southern to northern East Asia and correlated positively with the genome-wide proportion of southern East Asian ancestry, indicating that this putative positive selection likely occurred in the common ancestor of southern East Asian populations before the admixture with northern East Asian populations.


Assuntos
Haplótipos , Homem de Neandertal , Homem de Neandertal/genética , Animais , Humanos , Europa (Continente) , Ásia Oriental , Povo Asiático/genética , Cadeias Pesadas de Imunoglobulinas/genética , População Branca/genética , Evolução Molecular , Introgressão Genética , Seleção Genética , População do Leste Asiático
11.
Mol Biol Evol ; 41(4)2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38507661

RESUMO

Recent studies have suggested that dogs were domesticated during the Last Glacial Maximum (LGM) in Siberia, which contrasts with previous proposed domestication centers (e.g. Europe, the Middle East, and East Asia). Ancient DNA provides a powerful resource for the study of mammalian evolution and has been widely used to understand the genetic history of domestic animals. To understand the maternal genetic history of East Asian dogs, we have made a complete mitogenome dataset of 120 East Asian canids from 38 archaeological sites, including 102 newly sequenced from 12.9 to 1 ka BP (1,000 years before present). The majority (112/119, 94.12%) belonged to haplogroup A, and half of these (55/112, 49.11%) belonged to sub-haplogroup A1b. Most existing mitochondrial haplogroups were present in ancient East Asian dogs. However, mitochondrial lineages in ancient northern dogs (northeastern Eurasia and northern East Asia) were deeper and older than those in southern East Asian dogs. Results suggests that East Asian dogs originated from northeastern Eurasian populations after the LGM, dispersing in two possible directions after domestication. Western Eurasian (Europe and the Middle East) dog maternal ancestries genetically influenced East Asian dogs from approximately 4 ka BP, dramatically increasing after 3 ka BP, and afterwards largely replaced most primary maternal lineages in northern East Asia. Additionally, at least three major mitogenome sub-haplogroups of haplogroup A (A1a, A1b, and A3) reveal at least two major dispersal waves onto the Qinghai-Tibet Plateau in ancient times, indicating eastern (A1b and A3) and western (A1a) Eurasian origins.


Assuntos
Genoma Mitocondrial , Animais , Cães , Animais Domésticos/genética , Ásia Oriental , DNA Mitocondrial/genética , Variação Genética , Haplótipos , Mamíferos/genética , Filogenia
12.
Brief Bioinform ; 25(1)2023 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-38221906

RESUMO

Large-scale imputation reference panels are currently available and have contributed to efficient genome-wide association studies through genotype imputation. However, whether large-size multi-ancestry or small-size population-specific reference panels are the optimal choices for under-represented populations continues to be debated. We imputed genotypes of East Asian (180k Japanese) subjects using the Trans-Omics for Precision Medicine reference panel and found that the standard imputation quality metric (Rsq) overestimated dosage r2 (squared correlation between imputed dosage and true genotype) particularly in marginal-quality bins. Variance component analysis of Rsq revealed that the increased imputed-genotype certainty (dosages closer to 0, 1 or 2) caused upward bias, indicating some systemic bias in the imputation. Through systematic simulations using different template switching rates (θ value) in the hidden Markov model, we revealed that the lower θ value increased the imputed-genotype certainty and Rsq; however, dosage r2 was insensitive to the θ value, thereby causing a deviation. In simulated reference panels with different sizes and ancestral diversities, the θ value estimates from Minimac decreased with the size of a single ancestry and increased with the ancestral diversity. Thus, Rsq could be deviated from dosage r2 for a subpopulation in the multi-ancestry panel, and the deviation represents different imputed-dosage distributions. Finally, despite the impact of the θ value, distant ancestries in the reference panel contributed only a few additional variants passing a predefined Rsq threshold. We conclude that the θ value substantially impacts the imputed dosage and the imputation quality metric value.


Assuntos
Estudo de Associação Genômica Ampla , Polimorfismo de Nucleotídeo Único , Humanos , Frequência do Gene , Genótipo
13.
Proc Natl Acad Sci U S A ; 119(28): e2121388119, 2022 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-35759654

RESUMO

East Africa is a global biodiversity hotspot and exhibits distinct longitudinal diversity gradients from west to east in freshwater fishes and forest mammals. The assembly of this exceptional biodiversity and the drivers behind diversity gradients remain poorly understood, with diversification often studied at local scales and less attention paid to biotic exchange between Afrotropical regions. Here, we reconstruct a river system that existed for several millennia along the now semiarid Kenya Rift Valley during the humid early Holocene and show how this river system influenced postglacial dispersal of fishes and mammals due to its dual role as a dispersal corridor and barrier. Using geomorphological, geochronological, isotopic, and fossil analyses and a synthesis of radiocarbon dates, we find that the overflow of Kenyan rift lakes between 12 and 8 ka before present formed a bidirectional river system consisting of a "Northern River" connected to the Nile Basin and a "Southern River," a closed basin. The drainage divide between these rivers represented the only viable terrestrial dispersal corridor across the rift. The degree and duration of past hydrological connectivity between adjacent river basins determined spatial diversity gradients for East African fishes. Our reconstruction explains the isolated distribution of Nilotic fish species in modern Kenyan rift lakes, Guineo-Congolian mammal species in forests east of the Kenya Rift, and recent incipient vertebrate speciation and local endemism in this region. Climate-driven rearrangements of drainage networks unrelated to tectonic activity contributed significantly to the assembly of species diversity and modern faunas in the East African biodiversity hotspot.


Assuntos
Biodiversidade , Rios , Animais , Peixes , Fósseis , Quênia , Lagos , Mamíferos
14.
Proc Natl Acad Sci U S A ; 119(34): e2207199119, 2022 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-35969742

RESUMO

Caves are home to unique and fragile biotas with high levels of endemism. However, little is known about how the biotic colonization of caves has developed over time, especially in caves from middle and low latitudes. Subtropical East Asia holds the world's largest karst landform with numerous ancient caves, which harbor a high diversity of cave-dwelling organisms and are regarded as a biodiversity hotspot. Here, we assess the temporal dynamics of biotic colonization of subtropical East Asian caves through a multi-taxon analysis with representatives of green plants, animals, and fungi. We then investigate the consequences of paleonviromental changes on the colonization dynamics of these caves in combination with reconstructions of vegetation, temperature, and precipitation. We discover that 88% of cave colonization events occurred after the Oligocene-Miocene boundary, and organisms from the surrounding forest were a major source for subtropical East Asian cave biodiversity. Biotic colonization of subtropical East Asian caves during the Neogene was subject to periods of acceleration and decrease, in conjunction with large-scale, seasonal climatic changes and evolution of local forests. This study highlights the long-term evolutionary interaction between surface and cave biotas; our climate-vegetation-relict model proposed for the subtropical East Asian cave biota may help explain the evolutionary origins of other mid-latitude subterranean biotas.


Assuntos
Biodiversidade , Cavernas , Florestas , Animais , Ásia Oriental , Filogenia
15.
Proc Natl Acad Sci U S A ; 119(39): e2211234119, 2022 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-36122246

RESUMO

Whether or not nonavian dinosaur biodiversity declined prior to the end-Cretaceous mass extinction remains controversial as the result of sampling biases in the fossil record, differences in the analytical approaches used, and the rarity of high-precision geochronological dating of dinosaur fossils. Using magnetostratigraphy, cyclostratigraphy, and biostratigraphy, we establish a high-resolution geochronological framework for the fossil-rich Late Cretaceous sedimentary sequence in the Shanyang Basin of central China. We have found only three dinosaurian eggshell taxa (Macroolithus yaotunensis, Elongatoolithus elongatus, and Stromatoolithus pinglingensis) representing two clades (Oviraptoridae and Hadrosauridae) in sediments deposited between ∼68.2 and ∼66.4 million y ago, indicating sustained low dinosaur biodiversity, and that assessment is consistent with the known skeletal remains in the Shanyang and surrounding basins of central China. Along with the dinosaur eggshell records from eastern and southern China, we find a decline in dinosaur biodiversity from the Campanian to the Maastrichtian. Our results support a long-term decline in global dinosaur biodiversity prior to 66 million y ago, which likely set the stage for the end-Cretaceous nonavian dinosaur mass extinction.


Assuntos
Biodiversidade , Dinossauros , Extinção Biológica , Fósseis , Animais , China , Dinossauros/classificação
16.
Proc Natl Acad Sci U S A ; 119(23): e2120335119, 2022 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-35639698

RESUMO

SignificanceThe western Pacific subtropical high (WPSH) channels moisture from the tropics that underpins the East Asian summer climate. Interannual variability of the WPSH dominates climate extremes in the densely populated countries of East Asia. In 2020, an anomalously strong WPSH led to catastrophic floods with hundreds of deaths, 28,000 homes destroyed, and tens of billions in economic damage in China alone. How the frequency of such strong WPSH events will change is of great societal concern. Our finding of an increase in future WPSH variability, translating into an increased frequency of climate extreme as seen in the 2020 episode, highlights the increased risks for the billions of people in the densely populated East Asia with profound socioeconomic consequences.

17.
Proc Natl Acad Sci U S A ; 119(30): e2205602119, 2022 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-35862459

RESUMO

Comprehensive knowledge of the distribution of active hydrothermal vent fields along midocean ridges is essential to understanding global chemical and heat fluxes and endemic faunal distributions. However, current knowledge is biased by a historical preference for on-axis surveys. A scarcity of high-resolution bathymetric surveys in off-axis regions limits vent identification, which implies that the number of vents may be underestimated. Here, we present the discovery of an active, high-temperature, off-axis hydrothermal field on a fast-spreading ridge. The vent field is located 750 m east of the East Pacific Rise axis and ∼7 km north of on-axis vents at 9° 50'N, which are situated in a 50- to 100-m-wide trough. This site is currently the largest vent field known on the East Pacific Rise between 9 and 10° N. Its proximity to a normal fault suggests that hydrothermal fluid pathways are tectonically controlled. Geochemical evidence reveals deep fluid circulation to depths only 160 m above the axial magma lens. Relative to on-axis vents at 9° 50'N, these off-axis fluids attain higher temperatures and pressures. This tectonically controlled vent field may therefore exhibit greater stability in fluid composition, in contrast to more dynamic, dike-controlled, on-axis vents. The location of this site indicates that high-temperature convective circulation cells extend to greater distances off axis than previously realized. Thorough high-resolution mapping is necessary to understand the distribution, frequency, and physical controls on active off-axis vent fields so that their contribution to global heat and chemical fluxes and role in metacommunity dynamics can be determined.


Assuntos
Fontes Hidrotermais , Biodiversidade , Ecossistema , Oceano Pacífico
18.
BMC Bioinformatics ; 25(1): 150, 2024 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-38616247

RESUMO

BACKGROUND: The Eastern Africa Network for Bioinformatics Training (EANBiT) has matured through continuous evaluation, feedback, and codesign. We highlight how the program has evolved to meet challenges and achieve its goals and how experiential learning through mini projects enhances the acquisition of skills and collaboration. We continued to learn and grow through honest feedback and evaluation of the program, trainers, and modules, enabling us to provide robust training even during the Coronavirus disease 2019 (COVID-19) pandemic, when we had to redesign the program due to restricted travel and in person group meetings. RESULTS: In response to the pandemic, we developed a program to maintain "residential" training experiences and benefits remotely. We had to answer the following questions: What must change to still achieve the RT goals? What optimal platforms should be used? How would we manage connectivity and data challenges? How could we avoid online fatigue? Going virtual presented an opportunity to reflect on the essence and uniqueness of the program and its ability to meet the objective of strengthening bioinformatics skills among the cohorts of students using different delivery approaches. It allowed an increase in the number of participants. Evaluating each program component is critical for improvement, primarily when feedback feeds into the program's continuous amendment. Initially, the participants noted that there were too many modules, insufficient time, and a lack of hands-on training as a result of too much focus on theory. In the subsequent iterations, we reduced the number of modules from 27 to five, created a harmonized repository for the materials on GitHub, and introduced project-based learning through the mini projects. CONCLUSION: We demonstrate that implementing a program design through detailed monitoring and evaluation leads to success, especially when participants who are the best fit for the program are selected on an appropriate level of skills, motivation, and commitment.


Assuntos
COVID-19 , Aprendizagem , Humanos , África Oriental , COVID-19/epidemiologia , Biologia Computacional , Pandemias
19.
Emerg Infect Dis ; 30(8): 1599-1608, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39043406

RESUMO

Bacterial zoonoses are established causes of severe febrile illness in East Africa. Within a fever etiology study, we applied a high-throughput 16S rRNA metagenomic assay validated for detecting bacterial zoonotic pathogens. We enrolled febrile patients admitted to 2 referral hospitals in Moshi, Tanzania, during September 2007-April 2009. Among 788 participants, median age was 20 (interquartile range 2-38) years. We performed PCR amplification of V1-V2 variable region 16S rRNA on cell pellet DNA, then metagenomic deep-sequencing and pathogenic taxonomic identification. We detected bacterial zoonotic pathogens in 10 (1.3%) samples: 3 with Rickettsia typhi, 1 R. conorii, 2 Bartonella quintana, 2 pathogenic Leptospira spp., and 1 Coxiella burnetii. One other sample had reads matching a Neoerhlichia spp. previously identified in a patient from South Africa. Our findings indicate that targeted 16S metagenomics can identify bacterial zoonotic pathogens causing severe febrile illness in humans, including potential novel agents.


Assuntos
Febre , Metagenômica , RNA Ribossômico 16S , Humanos , Tanzânia/epidemiologia , Adulto , Pré-Escolar , Adolescente , Metagenômica/métodos , Febre/microbiologia , Masculino , Feminino , Animais , Criança , RNA Ribossômico 16S/genética , Adulto Jovem , Bactérias/genética , Bactérias/classificação , Bactérias/isolamento & purificação , Zoonoses Bacterianas/microbiologia , Zoonoses Bacterianas/epidemiologia , Infecções Bacterianas/microbiologia , Infecções Bacterianas/epidemiologia , Infecções Bacterianas/diagnóstico , Zoonoses/microbiologia , Zoonoses/epidemiologia
20.
Emerg Infect Dis ; 30(3): 581-585, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38407189

RESUMO

Middle East respiratory syndrome coronavirus (MERS-CoV) is endemic in dromedaries in Africa, but camel-to-human transmission is limited. Sustained 12-month sampling of dromedaries in a Kenya abattoir hub showed biphasic MERS-CoV incidence; peak detections occurred in October 2022 and February 2023. Dromedary-exposed abattoir workers (7/48) had serologic signs of previous MERS-CoV exposure.


Assuntos
Camelus , Coronavírus da Síndrome Respiratória do Oriente Médio , Humanos , Animais , Quênia/epidemiologia , Incidência , Matadouros
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