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1.
Mutat Res ; 852: 503164, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32265042

RESUMEN

In central Brazil, in the municipality of Faina (state of Goiás), the small and isolated village of Araras comprises a genetic cluster of xeroderma pigmentosum (XP) patients. The high level of consanguinity and the geographical isolation gave rise to a high frequency of XP patients. Recently, two founder events were identified affecting that community, with two independent mutations at the POLH gene, c.764 + 1 G > A (intron 6) and c.907 C > T; p.Arg303* (exon 8). These deleterious mutations lead to the xeroderma pigmentosum variant syndrome (XP-V). Previous reports identified both mutations in other countries: the intron 6 mutation in six patients (four families) from Northern Spain (Basque Country and Cantabria) and the exon 8 mutation in two patients from different families in Europe, one of them from Kosovo. In order to investigate the ancestry of the XP patients and the age for these mutations at Araras, we generated genotyping information for 22 XP-V patients from Brazil (16), Spain (6) and Kosovo (1). The local genomic ancestry and the shared haplotype segments among the patients showed that the intron 6 mutation at Araras is associated with an Iberian genetic legacy. All patients from Goiás, homozygotes for intron 6 mutation, share with the Spanish patients identical-by-descent (IBD) genomic segments comprising the mutation. The entrance date for the Iberian haplotype at the village was calculated to be approximately 200 years old. This result is in agreement with the historical arrival of Iberian individuals at the Goiás state (BR). Patients from Goiás and the three families from Spain share 1.8 cM (family 14), 1.7 cM (family 15), and a more significant segment of 4.7 cM within family 13. On the other hand, the patients carrying the exon 8 mutation do not share any specific genetic segment, indicating an old genetic distance between them or even no common ancestry.


Asunto(s)
ADN Polimerasa Dirigida por ADN/genética , Haplotipos , Patrón de Herencia , Mutación , Aislamiento Reproductivo , Xerodermia Pigmentosa/genética , Brasil/epidemiología , Consanguinidad , Europa (Continente)/epidemiología , Exones , Femenino , Genética de Población , Heterocigoto , Homocigoto , Migración Humana , Humanos , Intrones , Masculino , Fenotipo , Xerodermia Pigmentosa/epidemiología , Xerodermia Pigmentosa/patología
3.
PLoS Genet ; 16(3): e1008552, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32150539

RESUMEN

The genetic diversity of humans, like many species, has been shaped by a complex pattern of population separations followed by isolation and subsequent admixture. This pattern, reaching at least as far back as the appearance of our species in the paleontological record, has left its traces in our genomes. Reconstructing a population's history from these traces is a challenging problem. Here we present a novel approach based on the Multiple Sequentially Markovian Coalescent (MSMC) to analyze the separation history between populations. Our approach, called MSMC-IM, uses an improved implementation of the MSMC (MSMC2) to estimate coalescence rates within and across pairs of populations, and then fits a continuous Isolation-Migration model to these rates to obtain a time-dependent estimate of gene flow. We show, using simulations, that our method can identify complex demographic scenarios involving post-split admixture or archaic introgression. We apply MSMC-IM to whole genome sequences from 15 worldwide populations, tracking the process of human genetic diversification. We detect traces of extremely deep ancestry between some African populations, with around 1% of ancestry dating to divergences older than a million years ago.


Asunto(s)
Flujo Génico/genética , Genoma Humano/genética , Grupo de Ascendencia Continental Africana/genética , Variación Genética/genética , Haplotipos/genética , Migración Humana , Humanos , Modelos Genéticos , Densidad de Población , Secuenciación Completa del Genoma/métodos
4.
Nat Commun ; 11(1): 924, 2020 02 17.
Artículo en Inglés | MEDLINE | ID: mdl-32066741

RESUMEN

There is little evidence for the role of plant foods in the dispersal of early modern humans into new habitats globally. Researchers have hypothesised that early movements of human populations through Island Southeast Asia and into Sahul were driven by the lure of high-calorie, low-handling-cost foods, and that the use of plant foods requiring processing was not common in Sahul until the Holocene. Here we present the analysis of charred plant food remains from Madjedbebe rockshelter in northern Australia, dated to between 65 kya and 53 kya. We demonstrate that Australia's earliest known human population exploited a range of plant foods, including those requiring processing. Our finds predate existing evidence for such subsistence practices in Sahul by at least 23ky. These results suggest that dietary breadth underpinned the success of early modern human populations in this region, with the expenditure of labour on the processing of plants guaranteeing reliable access to nutrients in new environments.


Asunto(s)
Domesticación , Conducta Alimentaria , Migración Humana/historia , Plantas Comestibles , Australia , Manipulación de Alimentos/historia , Fósiles , Historia Antigua , Humanos
5.
Nat Commun ; 11(1): 939, 2020 02 24.
Artículo en Inglés | MEDLINE | ID: mdl-32094358

RESUMEN

The island of Sardinia has been of particular interest to geneticists for decades. The current model for Sardinia's genetic history describes the island as harboring a founder population that was established largely from the Neolithic peoples of southern Europe and remained isolated from later Bronze Age expansions on the mainland. To evaluate this model, we generate genome-wide ancient DNA data for 70 individuals from 21 Sardinian archaeological sites spanning the Middle Neolithic through the Medieval period. The earliest individuals show a strong affinity to western Mediterranean Neolithic populations, followed by an extended period of genetic continuity on the island through the Nuragic period (second millennium BCE). Beginning with individuals from Phoenician/Punic sites (first millennium BCE), we observe spatially-varying signals of admixture with sources principally from the eastern and northern Mediterranean. Overall, our analysis sheds light on the genetic history of Sardinia, revealing how relationships to mainland populations shifted over time.


Asunto(s)
ADN Antiguo , ADN Mitocondrial/genética , Genética de Población/historia , Migración Humana , Modelos Genéticos , Arqueología/métodos , Restos Mortales , Cromosomas Humanos X/genética , Cromosomas Humanos Y/genética , Conjuntos de Datos como Asunto , Femenino , Historia del Siglo XV , Historia del Siglo XVI , Historia del Siglo XVII , Historia del Siglo XVIII , Historia del Siglo XIX , Historia del Siglo XX , Historia del Siglo XXI , Historia Antigua , Historia Medieval , Humanos , Italia , Masculino , Análisis de Secuencia de ADN
7.
Gene ; 735: 144399, 2020 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-32001374

RESUMEN

The origin of Arab-speaking population is classified according to their geographical location, ethnic background, and historical influx of nearby and distant populations. Data on HLA class I and class II loci in (Arabian Peninsula) Bahraini population are lacking. We analyzed HLA genetic profile of Bahrainis with neighboring communities, and with Levantines, North Africans, Sub-Saharans, Europeans, and Asians, using genetic distances, neighbor-joining dendrograms, correspondence and haplotype analysis. HLA class I and class II genotyping were done by high resolution PCR-SSP in 175 Bahraini subjects. In total, 19 HLA-A, 33 HLA-B, 15 HLA-C, 14 DRB1 and 7 DQB1 alleles were identified. The most common class I alleles were A*02:01:01 (18.3%), A*01:01:01(15.4%), B*35:01:02 (12.9%), C*12:01:01 (15.1%), and C*04:01:01 (14.9%), while DRB1*03:01:01 (18.0%), DQB1*02:01:01 (29.1%), and DQB1*05:01:01 (24.9%) were the most frequent class II alleles. Significant linkage disequilibrium was seen between all HLA loci pairs. DRB1*03:01:01-DQB1*02:01:01 (15.18%) was the most frequent two-locus haplotype. Significant negative Fnd values were observed, indicating balancing selection at studied loci. Bahrainis appear to be related to Western Mediterranean (North Africans, Iberians and French), but relatively distinct from Levantines (Palestinians, Lebanese, and Jordanians) and Sub-Saharans. This indicates limited genetic contribution of Levantine Arabs and Sub-Saharans to the Bahraini gene pool.


Asunto(s)
Frecuencia de los Genes , Antígenos HLA/genética , Haplotipos , Población/genética , Bahrein , Femenino , Antígenos HLA/clasificación , Migración Humana , Humanos , Desequilibrio de Ligamiento , Masculino , Filogenia
8.
PLoS One ; 15(2): e0228584, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32023309

RESUMEN

BACKGROUND: Migrants from high endemic countries accounted for 18% of newly diagnosed HIV infections in Europe in 2017. Knowledge on the link between HIV risk and post-migration travels and their impact on HIV acquisition is scarce, but critical to inform prevention. This study aims to explore risky sexual behaviour and HIV-acquisition among sub-Saharan African migrants, and to assess post-migration mobility as a determinant of sexual risk behaviour. METHODS: Data from two cross-sectional bio-behavioural surveys to assess HIV-prevalence conducted in Lisbon and Antwerp were analysed to explore migration-related characteristics, travel patterns, and sexual risk taking in the host country and abroad. Bi- and multivariate associations were estimated through adjusted odds ratios and 95% confidence intervals; multivariable logistic regression determined factors associated with condomless sexual intercourse. RESULTS: Among N = 1508 participants above 18 years (58% males), 68% travelled post-migration (49.2% reported intercourse abroad). The overall proportion of condomless sex at last sexual intercourse was high (68.1%). The odds of condomless sex in the host country was five times higher when the last sexual intercourse abroad was also condomless [OR:5.32; 95%CI:2.98-9.25]. About half of the travellers reported concurrency, i.e. a regular partner in the host country while having other sexual partners abroad. Almost three percent of the participants reported being HIV+, but 5% had a reactive HIV test-result, with similar proportions among travellers and non-travellers. Also, among the n = 75 participants with reactive HIV test-results, condomless sex occurred (n = 40) and was associated with mobility. CONCLUSIONS: Sub-Saharan African migrants are mobile and engage in sexual risk behaviours in the countries of residence and while travelling, increasing risk of post-migration HIV-acquisition. A transnational perspective on HIV prevention and sexual health promotion is needed for effectively reducing migrants' HIV risk related to their mobility.


Asunto(s)
Infecciones por VIH/epidemiología , Migrantes/estadística & datos numéricos , Sexo Inseguro/etnología , Adolescente , Adulto , África del Sur del Sahara , Ciudades/epidemiología , Europa (Continente) , Femenino , Migración Humana/estadística & datos numéricos , Humanos , Masculino , Persona de Mediana Edad , Migrantes/psicología , Sexo Inseguro/estadística & datos numéricos
9.
Mol Genet Genomics ; 295(3): 579-589, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-31932897

RESUMEN

We have determined the distribution of Y-chromosomal haplotypes and haplogroups in the Yong population, one of the largest and well-known ethnic groups that began migrating southward from China to Thailand centuries ago. Their unique mass migration pattern provided great opportunities for researchers to study the genetic links of the transboundary migration movements among the peoples of China, Myanmar and Thailand. We analysed relevant male-specific markers, such as Y-STRs and Y-SNPs, and the distribution of 23 Y-STRs of 111 Yong individuals and 116 nearby ethnic groups including the Shan, Northern Thai, Lawa, Lua, Skaw, Pwo and Padong groups. We found that the general haplogroup distribution values were similar among different populations; however, the haplogroups O1b-M268 and O2-M112 constituted the vast majority of these values. In contrast with previous maternal lineage studies, the paternal lineage of the Yong did not relate to the Xishuangbanna Dai people, who represent their historically documented ancestors. However, they did display a close genetic affinity to other prehistoric Tai-Kadai speaking groups in China such as the Zhuang and Bouyei. Low degrees of genetic admixture within the populations who belonged to the Austroasiatic and Sino-Tibetan linguistic families were observed in the gene pool of the Yong populations. Resettlement in northern Thailand in the early part of the nineteenth century AD, by way of mass migration trend, was able to preserve the Yong's ancestral genetic background in terms of the way they had previously lived in China and Myanmar. Our study has revealed similar genetic structures among ethnic populations in northern Thailand and southern China, and has identified and emphasized an ancient Tai-Kadai patrilineal ancestry line in the Yong ethnic group.


Asunto(s)
Cromosomas Humanos Y/genética , ADN Mitocondrial/genética , Grupos Étnicos/genética , Variación Genética , Genética de Población , Haplotipos , Herencia Paterna , Migración Humana , Humanos , Masculino , Tailandia
11.
Nature ; 577(7792): 665-670, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31969706

RESUMEN

Our knowledge of ancient human population structure in sub-Saharan Africa, particularly prior to the advent of food production, remains limited. Here we report genome-wide DNA data from four children-two of whom were buried approximately 8,000 years ago and two 3,000 years ago-from Shum Laka (Cameroon), one of the earliest known archaeological sites within the probable homeland of the Bantu language group1-11. One individual carried the deeply divergent Y chromosome haplogroup A00, which today is found almost exclusively in the same region12,13. However, the genome-wide ancestry profiles of all four individuals are most similar to those of present-day hunter-gatherers from western Central Africa, which implies that populations in western Cameroon today-as well as speakers of Bantu languages from across the continent-are not descended substantially from the population represented by these four people. We infer an Africa-wide phylogeny that features widespread admixture and three prominent radiations, including one that gave rise to at least four major lineages deep in the history of modern humans.


Asunto(s)
Grupo de Ascendencia Continental Africana/genética , Grupo de Ascendencia Continental Africana/historia , Conducta Alimentaria/etnología , Migración Humana/historia , Filogenia , Alelos , Animales , Arqueología , Entierro , Camerún , Niño , Preescolar , Cromosomas Humanos Y/genética , ADN Antiguo/análisis , Femenino , Marcadores Genéticos/genética , Genética de Población , Genoma Humano/genética , Haplotipos/genética , Historia Antigua , Humanos , Lenguaje/historia , Masculino , Pan troglodytes/genética , Análisis de Componente Principal
12.
PLoS One ; 15(1): e0227137, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31999719

RESUMEN

Across the world, certain schools struggle to recruit and retain qualified teachers. This study explores teacher mobility across schools in rural China. Using a dataset from the Gansu Survey of Children and Families, this study investigates how teacher's initial job placement relates to teacher mobility across schools. The findings show that non-local teachers whose initial placements were not in their hometowns were more likely to switch schools. Non-local teachers were also more likely to move for family reasons, compared to moving for personal development or due to involuntary transfer by the local government. The findings suggest that localized recruitment and deployment of teachers can be valuable for reducing teacher mobility rate and retaining teachers in hard-to-staff areas.


Asunto(s)
Empleo/estadística & datos numéricos , Migración Humana , Maestros/estadística & datos numéricos , Adulto , China , Femenino , Humanos , Masculino , Persona de Mediana Edad , Población Rural
13.
Science ; 367(6474): 147-148, 2020 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-31919210
14.
MMWR Morb Mortal Wkly Rep ; 69(1): 10-13, 2020 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-31917781

RESUMEN

Tailoring communicable disease preparedness and response strategies to unique population movement patterns between an outbreak area and neighboring countries can help limit the international spread of disease. Global recognition of the value of addressing community connectivity in preparedness and response, through field work and visualizing the identified movement patterns, is reflected in the World Health Organization's declaration on July 17, 2019, that the 10th Ebola virus disease (Ebola) outbreak in the Democratic Republic of the Congo (DRC) was a Public Health Emergency of International Concern (1). In March 2019, the Infectious Diseases Institute (IDI), Uganda, in collaboration with the Ministry of Health (MOH) Uganda and CDC, had previously identified areas at increased risk for Ebola importation by facilitating community engagement with participatory mapping to characterize cross-border population connectivity patterns. Multisectoral participants identified 31 locations and associated movement pathways with high levels of connectivity to the Ebola outbreak areas. They described a major shift in the movement pattern between Goma (DRC) and Kisoro (Uganda), mainly through Rwanda, when Rwanda closed the Cyanika ground crossing with Uganda. This closure led some travelers to use a potentially less secure route within DRC. District and national leadership used these results to bolster preparedness at identified points of entry and health care facilities and prioritized locations at high risk further into Uganda, especially markets and transportation hubs, for enhanced preparedness. Strategies to forecast, identify, and rapidly respond to the international spread of disease require adapting to complex, dynamic, multisectoral cross-border population movement, which can be influenced by border control and public health measures of neighboring countries.


Asunto(s)
Brotes de Enfermedades , Fiebre Hemorrágica Ebola/epidemiología , Migración Humana/estadística & datos numéricos , Participación de la Comunidad , República Democrática del Congo/epidemiología , Brotes de Enfermedades/prevención & control , Fiebre Hemorrágica Ebola/prevención & control , Humanos , Rwanda/epidemiología , Uganda/epidemiología
15.
PLoS One ; 15(1): e0227436, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31968017

RESUMEN

Sea level rise in the United States will lead to large scale migration in the future. We propose a framework to examine future climate migration patterns using models of human migration. Our framework requires that we distinguish between historical versus climate driven migration and recognizes how the impacts of climate change can extend beyond the affected area. We apply our framework to simulate how migration, driven by sea level rise, differs from baseline migration patterns. Specifically, we couple a sea level rise model with a data-driven model of human migration and future population projections, creating a generalized joint model of climate driven migration that can be used to simulate population distributions under potential future sea level rise scenarios. The results of our case study suggest that the effects of sea level rise are pervasive, expanding beyond coastal areas via increased migration, and disproportionately affecting some areas of the United States.


Asunto(s)
Migración Humana , Modelos Teóricos , Elevación del Nivel del Mar , Humanos , Estados Unidos
16.
Integr Zool ; 15(1): 32-39, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30983102

RESUMEN

Despite studies on range shifts being abundant, the problem of dispersal barriers limiting climate migrants' movement is yet to be fully included into any modeling framework. For this reason, we introduce a novel concept whereby the interplay of range shifts and dispersal barriers of a particular spatial configuration can threaten the persistence of populations under a climate change scenario. We named this concept "C-trap," based on the topographic shape of such barriers. After elaborating on the theoretical features of C-traps, we provide a simple method that combines environmental data and future climate projections to locate them spatially. We use this method to determine where high C-trap densities have the potential to further threaten the conservation of endangered, endemic animals across the world's terrestrial realm, in a climate change scenario. Our methodology detected potential C-traps for the study system, with areas of high density mostly located in east Europe, south Asia and North America. However, finer-scale analyses are required to assess the magnitude of the threat locally. Dispersal barriers add an additional dimension to range shift studies and can ultimately prevent otherwise successful climate migrants from tracking their climatic niche. The methodology presented here is simple and flexible enough to be adapted to a wide range of taxa and locations as well as the fast development of range shift modeling. Therefore, we encourage researchers to include the effects of anthropogenic dispersal barriers in range shifts models and in the planning of effective conservation strategies with reference to climate change.


Asunto(s)
Cambio Climático , Migración Humana , Modelos Teóricos , Humanos
17.
Disasters ; 44(2): 390-407, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31231822

RESUMEN

Prospective, community-based surveillance systems for measuring birth, death, and population movement rates may have advantages over the 'gold-standard' retrospective household survey in humanitarian contexts. A community-based, monthly surveillance system was established in South Kivu, Democratic Republic of the Congo, in partnership with a local implementing partner and the national ministry of health. Data were collected on the occurrence of births, deaths, arrivals, and departures over the course of one year, and a retrospective survey was conducted at the end of the period to validate the information. Discrepancies between the two approaches were resolved by a third visit to the households with discordant records. The study found that the surveillance system was superior in terms of its specificity and sensitivity in measuring crude mortality and birth rates as compared to the survey, demonstrating the method's potential to measure accurately important population-level health metrics in an insecure setting in a timely, community-acceptable manner.


Asunto(s)
Tasa de Natalidad , Migración Humana , Mortalidad , Vigilancia de la Población/métodos , Adulto , República Democrática del Congo/epidemiología , Femenino , Humanos , Masculino , Sistemas de Socorro , Reproducibilidad de los Resultados , Estudios Retrospectivos , Encuestas y Cuestionarios
18.
PLoS One ; 14(12): e0225049, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31800577

RESUMEN

This paper investigates the correlation between climate, environment and human land use in the Westernmost Mediterranean on both sides of the Strait of Gibraltar during the Late Glacial. Using a multi-proxy approach on a sample of 300 sites from the Solutrean and Magdalenian of the Iberian Peninsula and from the Iberomaurusian in Morocco, we find evidence for significant changes in settlement patterns and site density after the Last Glacial Maximum. In Southern Iberia, during Heinrich Stadial 1, hyperarid zones expanded drastically from the south-eastern coast to the West through the Interior. This aridification process heavily affected Magdalenian settlement in the South and caused a strong decline of hunter-gatherer population. Southern Iberia during Heinrich Stadial 1 turned out to be a high-risk environment when compared to Northern Iberia. At the same time, the Late Iberomaurusian of Morocco, although considered to be situated in a high-risk environment as well, experiences an increase of sites and expansion of settlement area.


Asunto(s)
Agricultura , Cambio Climático , Migración Humana , Humanos , Región Mediterránea , Datación Radiométrica , Suelo/química
19.
PLoS One ; 14(12): e0225193, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31800583

RESUMEN

With approximately half of the world's population at risk of contracting dengue, this mosquito-borne disease is of global concern. International travellers significantly contribute to dengue's rapid and large-scale spread by importing the disease from endemic into non-endemic countries. To prevent future outbreaks and dengue from establishing in non-endemic countries, knowledge about the arrival time and location of infected travellers is crucial. We propose a network model that predicts the monthly number of dengue-infected air passengers arriving at any given airport. We consider international air travel volumes to construct weighted networks, representing passenger flows between airports. We further calculate the probability of passengers, who travel through the international air transport network, being infected with dengue. The probability of being infected depends on the destination, duration and timing of travel. Our findings shed light onto dengue importation routes and reveal country-specific reporting rates that have been until now largely unknown. This paper provides important new knowledge about the spreading dynamics of dengue that is highly beneficial for public health authorities to strategically allocate the often limited resources to more efficiently prevent the spread of dengue.


Asunto(s)
Aeropuertos/estadística & datos numéricos , Dengue/epidemiología , Transmisión de Enfermedad Infecciosa/estadística & datos numéricos , Migración Humana/estadística & datos numéricos , Pandemias/estadística & datos numéricos , Aviación/estadística & datos numéricos , Dengue/transmisión , Humanos , Modelos Estadísticos
20.
PLoS One ; 14(12): e0226970, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31887180

RESUMEN

As the only route formed in the inner Qinghai-Tibet plateau, the Tang-Tibet Ancient Road promoted the extension of the Overland Silk Roads to the inner Qinghai-Tibet plateau. Considering the Complex geographical and environmental factors of inner Qinghai-Tibet Plateau, we constructed a weighted trade route network based on geographical integration factors, and then adopted the principle of minimum cost and the shortest path on the network to simulate the ancient Tang-Tibet Ancient Road. We then compared the locations of known key points documented in the literature, and found a significant correspondence in the Qinghai section. However, there was a certain deviation between the key points recorded in Tibetan section and the simulated route; we found that the reason is the relative oxygen content (ROC) became a limited factor of the choice of the Tibetan section road. Moreover, we argue that the warm and humid climate and the human migration to the hinterland of the Qinghai-Tibet plateau were the fundamental driving forces for the formation of the Tang-Tibet Ancient Road.


Asunto(s)
Clima , Geografía , Migración Humana/historia , Historia Antigua , Humanos , Seda , Tibet
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