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1.
Support Care Cancer ; 30(7): 6187-6193, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35438337

RESUMEN

PURPOSE: Stakeholder engagement is increasingly integrated into clinical research processes. We conducted a mixed methods analysis to describe stakeholders' (peer ostomates, ostomy nurses, telehealth engineers) perceptions of their engagement and participation in a multisite, randomized trial of a telehealth-delivered curriculum for cancer survivors with ostomies. METHODS: Stakeholder notes were analyzed using narrative analysis. We constructed a 15-item survey that assessed the following areas: adherence to stakeholder engagement principles, engagement/influence throughout the study process, impact on perceived well-being, and satisfaction. Stakeholders were invited to complete the survey anonymously. Quantitative survey data were tabulated through summary statistics. RESULTS: Across intervention sessions, an average of 7.7 ± 1.4 stakeholders attended and 2.6 ± 1.4 submitted a note per session. The survey response rate was 73% (11/15). Stakeholders reported high agreement that the study adhered to engagement principles (91% reciprocal relationships, 100% co-learning, partnership, and transparency/honesty/trust). They felt highly engaged (18% moderate, 73% great deal) and that they had influence on study initiation (27% moderate, 55% great deal), intervention delivery (9% moderate, 82% great deal), fidelity assessment (18% moderate, 73% great deal), analysis and interpretation (55% moderate, 27% great deal), and dissemination (45% moderate, 45% great deal). They reported high overall satisfaction with roles (91% great deal), believed the program was helpful for participants (91%), and that serving on study team benefited their own well-being (100%). CONCLUSIONS: Our strategy of stakeholder inclusion led to high engagement, input, satisfaction, and belief in success of program, which could be mirrored in other trials.


Asunto(s)
Supervivientes de Cáncer , Estomía , Automanejo , Telemedicina , Humanos , Automanejo/educación , Participación de los Interesados
2.
Support Care Cancer ; 30(2): 1139-1147, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34435212

RESUMEN

OBJECTIVES: An ostomy results in lifelong quality of life changes for a cancer survivor. We describe the greatest challenges reported from a randomized trial of cancer survivors with stomas (ostomies). METHODS: Cancer survivors with ostomies participating in a multi-site randomized prospective trial of an Ostomy Self-Management Telehealth (OSMT) program versus usual care (UC) were surveyed at six months post accrual. An open-ended question requested greatest challenges after ostomy surgery. Quantitative descriptive and qualitative analyses were used to examine greatest challenges reported. RESULTS: A total of 118 trial participants identified greatest challenges with 55 in the OSMT and 63 in the UC. Six conceptual domains were used to code comments-physical, psychological, social, and spiritual quality of life; ostomy-specific issues, and healthcare issues. The OSMT contributed 187 comments, and UC contributed 235 comments. Ostomy specific issues and social well-being had the most comments overall with UC contributing more comments in all domains except physical well-being. Word Clouds revealed post-operative and treatment-related issues and going out in public as the most common challenges in both groups. Word Clouds compared types of ostomies revealing bowel function challenges (colostomy group), difficulties going out in public (ileostomy group), and positive support (urostomy group). CONCLUSIONS: Fewer challenges submitted by the OSMT group provide the beginning evidence of the OSMT program impact. Dominant challenges across both groups were social well-being and ostomy care. Challenges varied by type of ostomy. Findings support long-term care and support for all cancer survivors with ostomies. TRIAL REGISTRATION: NCT02974634.


Asunto(s)
Supervivientes de Cáncer , Neoplasias , Estomía , Automanejo , Telemedicina , Humanos , Estudios Prospectivos , Calidad de Vida
3.
Curr Biol ; 30(24): R1478-R1481, 2020 12 21.
Artículo en Inglés | MEDLINE | ID: mdl-33352129

RESUMEN

The mode and tempo of human dispersal to the far-flung Pacific Islands has been a source of fascination for centuries. New ancient DNA data from the archipelago of Vanuatu shed light on the ancient migrations that shaped the history of human settlement in the Pacific.


Asunto(s)
ADN Antiguo , Migración Humana , Humanos , Nativos de Hawái y Otras Islas del Pacífico , Islas del Pacífico , Vanuatu
4.
Mol Biol Evol ; 35(4): 871-886, 2018 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-29301001

RESUMEN

A widely accepted two-wave scenario of human settlement of Oceania involves the first out-of-Africa migration circa 50,000 years ago (ya), and the more recent Austronesian expansion, which reached the Bismarck Archipelago by 3,450 ya. Whereas earlier genetic studies provided evidence for extensive sex-biased admixture between the incoming and the indigenous populations, some archaeological, linguistic, and genetic evidence indicates a more complicated picture of settlement. To study regional variation in Oceania in more detail, we have compiled a genome-wide data set of 823 individuals from 72 populations (including 50 populations from Oceania) and over 620,000 autosomal single nucleotide polymorphisms (SNPs). We show that the initial dispersal of people from the Bismarck Archipelago into Remote Oceania occurred in a "leapfrog" fashion, completely by-passing the main chain of the Solomon Islands, and that the colonization of the Solomon Islands proceeded in a bidirectional manner. Our results also support a divergence between western and eastern Solomons, in agreement with the sharp linguistic divide known as the Tryon-Hackman line. We also report substantial post-Austronesian gene flow across the Solomons. In particular, Santa Cruz (in Remote Oceania) exhibits extraordinarily high levels of Papuan ancestry that cannot be explained by a simple bottleneck/founder event scenario. Finally, we use simulations to show that discrepancies between different methods for dating admixture likely reflect different sensitivities of the methods to multiple admixture events from the same (or similar) sources. Overall, this study points to the importance of fine-scale sampling to understand the complexities of human population history.


Asunto(s)
Genoma Humano , Migración Humana , Nativos de Hawái y Otras Islas del Pacífico/genética , Flujo Génico , Flujo Genético , Humanos , Oceanía , Filogeografía
5.
Nature ; 538(7626): 510-513, 2016 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-27698418

RESUMEN

The appearance of people associated with the Lapita culture in the South Pacific around 3,000 years ago marked the beginning of the last major human dispersal to unpopulated lands. However, the relationship of these pioneers to the long-established Papuan people of the New Guinea region is unclear. Here we present genome-wide ancient DNA data from three individuals from Vanuatu (about 3,100-2,700 years before present) and one from Tonga (about 2,700-2,300 years before present), and analyse them with data from 778 present-day East Asians and Oceanians. Today, indigenous people of the South Pacific harbour a mixture of ancestry from Papuans and a population of East Asian origin that no longer exists in unmixed form, but is a match to the ancient individuals. Most analyses have interpreted the minimum of twenty-five per cent Papuan ancestry in the region today as evidence that the first humans to reach Remote Oceania, including Polynesia, were derived from population mixtures near New Guinea, before their further expansion into Remote Oceania. However, our finding that the ancient individuals had little to no Papuan ancestry implies that later human population movements spread Papuan ancestry through the South Pacific after the first peopling of the islands.


Asunto(s)
Pueblo Asiatico/genética , Genoma Humano/genética , Genómica , Migración Humana/historia , Nativos de Hawái y Otras Islas del Pacífico/genética , Filogenia , Femenino , Genética de Población , Historia Antigua , Humanos , Masculino , Nueva Guinea/etnología , Polinesia/etnología , Tonga , Vanuatu
7.
Science ; 352(6282): 235-9, 2016 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-26989198

RESUMEN

Although Neandertal sequences that persist in the genomes of modern humans have been identified in Eurasians, comparable studies in people whose ancestors hybridized with both Neandertals and Denisovans are lacking. We developed an approach to identify DNA inherited from multiple archaic hominin ancestors and applied it to whole-genome sequences from 1523 geographically diverse individuals, including 35 previously unknown Island Melanesian genomes. In aggregate, we recovered 1.34 gigabases and 303 megabases of the Neandertal and Denisovan genome, respectively. We use these maps of archaic sequences to show that Neandertal admixture occurred multiple times in different non-African populations, characterize genomic regions that are significantly depleted of archaic sequences, and identify signatures of adaptive introgression.


Asunto(s)
ADN/genética , Genoma Humano/genética , Nativos de Hawái y Otras Islas del Pacífico/genética , Hombre de Neandertal/genética , Animales , Variación Genética , Humanos , Melanesia , Análisis de Secuencia de ADN
8.
Am J Hum Biol ; 28(3): 431-5, 2016 05.
Artículo en Inglés | MEDLINE | ID: mdl-26450459

RESUMEN

OBJECTIVES: The aims of this study are to characterize the frequency of the derived allele at rs387907171 in populations from the islands of New Britain and Bougainville in Northern Island Melanesia, to confirm its association with lighter hair color, and to refine hypotheses regarding its evolutionary history. METHODS: rs387907171 was genotyped in 93 individuals from New Britain and 101 from Bougainville for whom quantitative assessments of skin and hair pigmentation were available. Combining these with existing data from other Melanesian islands we tested for differences in allele frequencies between islands and for associations with skin and hair pigmentation using ANOVA, including sex, age, and island affiliations as covariates. RESULTS: The derived allele at rs387907171 was observed in a single copy in the New Britain and Bougainville populations genotyped here. Its frequency differs significantly among islands in the region (χ(2) = 206.5, df = 3, P < 0.001). rs387907171 remains significantly, although weakly, associated with lighter hair pigmentation (F = 10.28, R(2) = 0.0125, P = 0.0014). This association increases when sex and age (F = 20.68, R(2) = 0.074, P < 7.92 × 10(-13) ) are included as covariates. CONCLUSIONS: The rs387907171 SNP exhibits strong allele frequency differences among islands in Northern Island Melanesia. Its absence from Bougainville, as well as the weak association with decreased hair color, indicates that additional alleles contribute to the blondism phenotype. Its geographic distribution suggests that a Lapita-mediated model for the dispersal of the derived allele at rs387907171 remains a viable evolutionary scenario. Am. J. Hum. Biol. 28:431-435, 2016. © 2015 Wiley Periodicals, Inc.


Asunto(s)
Frecuencia de los Genes , Color del Cabello/genética , Glicoproteínas de Membrana/genética , Oxidorreductasas/genética , Polimorfismo de Nucleótido Simple , Humanos , Melanesia , Glicoproteínas de Membrana/metabolismo , Oxidorreductasas/metabolismo , Fenotipo
9.
BMC Genet ; 16: 122, 2015 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-26482799

RESUMEN

BACKGROUND: Variation in human skin pigmentation evolved in response to the selective pressure of ultra-violet radiation (UVR). Selection to maintain darker skin in high UVR environments is expected to constrain pigmentation phenotype and variation in pigmentation loci. Consistent with this hypothesis, the gene MC1R exhibits reduced diversity in African populations from high UVR regions compared to low-UVR non-African populations. However, MC1R diversity in non-African populations that have evolved under high-UVR conditions is not well characterized. METHODS: In order to test the hypothesis that MC1R variation has been constrained in Melanesians the coding region of the MC1R gene was sequenced in 188 individuals from Northern Island Melanesia. The role of purifying selection was assessed using a modified McDonald Kreitman's test. Pairwise FST was calculated between Melanesian populations and populations from the 1000 Genomes Project. The SNP rs2228479 was genotyped in a larger sample (n = 635) of Melanesians and tested for associations with skin and hair pigmentation. RESULTS: We observe three nonsynonymous and two synonymous mutations. A modified McDonald Kreitman's test failed to detect a significant signal of purifying selection. Pairwise FST values calculated between the four islands sampled here indicate little regional substructure in MC1R. When compared to African, European, East and South Asian populations, Melanesians do not exhibit reduced population divergence (measured as FST) or a high proportion of haplotype sharing with Africans, as one might expect if ancestral haplotypes were conserved across high UVR populations in and out of Africa. The only common nonsynonymous polymorphism observed, rs2228479, is not significantly associated with skin or hair pigmentation in a larger sample of Melanesians. CONCLUSIONS: The pattern of sequence diversity here does not support a model of strong selective constraint on MC1R in Northern Island Melanesia This absence of strong constraint, as well as the recent population history of the region, may explain the observed frequencies of the derived rs2228479 allele. These results emphasize the complex genetic architecture of pigmentation phenotypes, which are controlled by multiple, possibly interacting loci. They also highlight the role that population history can play in influencing phenotypic diversity in the absence of strong natural selection.


Asunto(s)
Variación Genética , Receptor de Melanocortina Tipo 1/genética , Selección Genética , Pigmentación de la Piel/genética , Adulto , Secuencia de Bases , Frecuencia de los Genes/genética , Estudios de Asociación Genética , Genética de Población , Genoma Humano , Geografía , Haplotipos/genética , Humanos , Melanesia , Fenotipo , Polimorfismo de Nucleótido Simple/genética
10.
Am J Hum Genet ; 94(5): 721-33, 2014 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-24726474

RESUMEN

Archaeology, linguistics, and existing genetic studies indicate that Oceania was settled by two major waves of migration. The first migration took place approximately 40 thousand years ago and these migrants, Papuans, colonized much of Near Oceania. Approximately 3.5 thousand years ago, a second expansion of Austronesian-speakers arrived in Near Oceania and the descendants of these people spread to the far corners of the Pacific, colonizing Remote Oceania. To assess the female contribution of these two human expansions to modern populations and to investigate the potential impact of other migrations, we obtained 1,331 whole mitochondrial genome sequences from 34 populations spanning both Near and Remote Oceania. Our results quantify the magnitude of the Austronesian expansion and demonstrate the homogenizing effect of this expansion on almost all studied populations. With regards to Papuan influence, autochthonous haplogroups support the hypothesis of a long history in Near Oceania, with some lineages suggesting a time depth of 60 thousand years, and offer insight into historical interpopulation dynamics. Santa Cruz, a population located in Remote Oceania, is an anomaly with extreme frequencies of autochthonous haplogroups of Near Oceanian origin; simulations to investigate whether this might reflect a pre-Austronesian versus Austronesian settlement of the island failed to provide unequivocal support for either scenario.


Asunto(s)
ADN Mitocondrial/genética , Migración Humana , Madres/historia , Población/genética , Secuencia de Bases , Femenino , Historia Antigua , Humanos , Datos de Secuencia Molecular , Oceanía
11.
Am J Phys Anthropol ; 153(4): 551-8, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24382639

RESUMEN

Both poor fetal development and accelerated post-natal growth have been linked to adult dyslipidemias in many studies conducted in developed societies. It is not known, however, whether these relationships only characterize populations with typical Western diets or if they also may develop in groups at the early stages of a dietary transition. Our longitudinal study of traditional rural populations in the Southwest Pacific during a period of extremely rapid modernization in diet and life-styles shows a nascent association between child growth retardation, subsequent growth acceleration, and adult lipid values in spite of a continuing prevalence of very low lipid levels. However, our results do not entirely conform to results from populations with "modern" diets. Outcome (i.e., young adult) cholesterol and triglyceride levels are more consistently related to initial measures of body fat and growth in body fat measures than with stature, while outcome apo A-1 is more consistently related to initial stature or stature growth than to measures of body fat. We suggest this may reflect a pattern characteristic of the initial stages of "modernization" associated with dietary change, with stronger and more pervasive relationships emerging only later as populations complete the dietary transition.


Asunto(s)
Estatura , Peso Corporal , Lípidos/sangre , Nativos de Hawái y Otras Islas del Pacífico/estadística & datos numéricos , Cambio Social , Adolescente , Desarrollo del Adolescente , Adulto , Niño , Desarrollo Infantil , Preescolar , Dieta , Femenino , Encuestas Epidemiológicas , Humanos , Lactante , Estudios Longitudinales , Masculino , Melanesia , Adulto Joven
12.
Am J Phys Anthropol ; 153(4): 653-62, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24449225

RESUMEN

Pigmentation of the skin, hair, and eyes is a complex trait controlled by multiple genetic loci. Recently a non-synonymous mutation in the pigmentation candidate gene TYRP1 was shown to be significantly associated with a blond-hair phenotype in populations from the Solomon Islands. The distribution of this mutation in the islands of Northern Island Melanesia, where the blondism phenotype is also prevalent, was unknown. Here, we present data describing the distribution of this allele in 550 individuals sampled from across this region, and test for associations between genotype at this locus and quantitatively measured skin and hair pigmentation phenotype. We report that the frequency of the 93C allele is notably lower than observed in the Solomons (0.12 vs. 0.26). The allele exhibits significant geographic heterogeneity across the islands sampled (χ(2) = 108.4, P < 0.0001). It is observed at its highest frequencies on the islands of New Ireland and New Hanover, while being almost completely absent from the large island of New Britain. Using linear regression with age, sex, and island as covariates we report that, as in the Solomons, the 93C allele is significantly associated with a decrease in hair pigmentation but not skin pigmentation. We discuss the distribution of the 93C allele across the Southwest Pacific in light of its possible place of origin and dispersal.


Asunto(s)
Color del Cabello/genética , Adulto , Antropología Física , Femenino , Frecuencia de los Genes/genética , Genotipo , Humanos , Masculino , Melanesia/epidemiología , Fenotipo
13.
Am J Phys Anthropol ; 149(3): 435-46, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23042600

RESUMEN

This set of cross-sectional and longitudinal data from children and young adults in certain Bougainville and Solomon Islands populations undergoing rapid modernization during the period 1966-1986 reveals very different responses to essentially the same stimuli-the introduction and widespread availability of western dietary items and reductions in habitual activity. Our analyses of over 2,000 children and young adults first measured in 1966-1972, with follow-up surveys in 1968-1970 and 1985-1986, show changes in overweight/obesity in these communities have their onset around puberty, and are not related to differences in childhood growth stunting. The prevalence of overweight and obesity increased substantially during the period of this study among young adults, particularly women, and in groups with more Polynesian affinities, where the frequency of overweight (BMI ≥ 25) tripled over this 20-year interval. However, the BMI of the more Papuan groups on Bougainville remained remarkably stable, even though they were close to the epicenter of modernization during this period, the Bougainville Copper Mine.


Asunto(s)
Obesidad/epidemiología , Sobrepeso/epidemiología , Adolescente , Adulto , Análisis de Varianza , Estatura , Índice de Masa Corporal , Niño , Preescolar , Estudios Transversales , Femenino , Humanos , Lactante , Estudios Longitudinales , Masculino , Melanesia/epidemiología , Papúa Nueva Guinea/epidemiología , Pubertad
15.
PLoS Genet ; 4(10): e1000239, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18974871

RESUMEN

Recent studies have detailed a remarkable degree of genetic and linguistic diversity in Northern Island Melanesia. Here we utilize that diversity to examine two models of genetic and linguistic coevolution. The first model predicts that genetic and linguistic correspondences formed following population splits and isolation at the time of early range expansions into the region. The second is analogous to the genetic model of isolation by distance, and it predicts that genetic and linguistic correspondences formed through continuing genetic and linguistic exchange between neighboring populations. We tested the predictions of the two models by comparing observed and simulated patterns of genetic variation, genetic and linguistic trees, and matrices of genetic, linguistic, and geographic distances. The data consist of 751 autosomal microsatellites and 108 structural linguistic features collected from 33 Northern Island Melanesian populations. The results of the tests indicate that linguistic and genetic exchange have erased any evidence of a splitting and isolation process that might have occurred early in the settlement history of the region. The correlation patterns are also inconsistent with the predictions of the isolation by distance coevolutionary process in the larger Northern Island Melanesian region, but there is strong evidence for the process in the rugged interior of the largest island in the region (New Britain). There we found some of the strongest recorded correlations between genetic, linguistic, and geographic distances. We also found that, throughout the region, linguistic features have generally been less likely to diffuse across population boundaries than genes. The results from our study, based on exceptionally fine-grained data, show that local genetic and linguistic exchange are likely to obscure evidence of the early history of a region, and that language barriers do not particularly hinder genetic exchange. In contrast, global patterns may emphasize more ancient demographic events, including population splits associated with the early colonization of major world regions.


Asunto(s)
Evolución Biológica , Etnicidad/genética , Variación Genética , Lenguaje , Alelos , Cromosomas Humanos Y/genética , Simulación por Computador , ADN Mitocondrial/genética , Geografía , Humanos , Lingüística , Masculino , Melanesia , Repeticiones de Microsatélite , Modelos Biológicos , Filogenia
16.
J Biol Rhythms ; 23(4): 330-40, 2008 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-18663240

RESUMEN

The daily biological clock regulates the timing of sleep and physiological processes that are of fundamental importance to human health, performance, and well-being. Environmental parameters of relevance to biological clocks include (1) daily fluctuations in light intensity and temperature, and (2) seasonal changes in photoperiod (day length) and temperature; these parameters vary dramatically as a function of latitude and locale. In wide-ranging species other than humans, natural selection has genetically optimized adaptiveness along latitudinal clines. Is there evidence for selection of clock gene alleles along latitudinal/photoperiod clines in humans? A number of polymorphisms in the human clock genes Per2, Per3, Clock, and AANAT have been reported as alleles that could be subject to selection. In addition, this investigation discovered several novel polymorphisms in the human Arntl and Arntl2 genes that may have functional impact upon the expression of these clock transcriptional factors. The frequency distribution of these clock gene polymorphisms is reported for diverse populations of African Americans, European Americans, Ghanaians, Han Chinese, and Papua New Guineans (including 5 subpopulations within Papua New Guinea). There are significant differences in the frequency distribution of clock gene alleles among these populations. Population genetic analyses indicate that these differences are likely to arise from genetic drift rather than from natural selection.


Asunto(s)
Relojes Biológicos/genética , Ritmo Circadiano/genética , Genes , Población/genética , Transactivadores/genética , Factores de Transcripción ARNTL , Negro o Afroamericano , Alelos , Pueblo Asiatico , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Relojes Biológicos/fisiología , Proteínas CLOCK , Ritmo Circadiano/fisiología , ADN/genética , Frecuencia de los Genes , Ghana , Humanos , Luz , Nueva Guinea , Fotoperiodo , Polimorfismo Genético , Estaciones del Año , Temperatura , Estados Unidos , Población Blanca
17.
PLoS Genet ; 4(1): e19, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18208337

RESUMEN

Human genetic diversity in the Pacific has not been adequately sampled, particularly in Melanesia. As a result, population relationships there have been open to debate. A genome scan of autosomal markers (687 microsatellites and 203 insertions/deletions) on 952 individuals from 41 Pacific populations now provides the basis for understanding the remarkable nature of Melanesian variation, and for a more accurate comparison of these Pacific populations with previously studied groups from other regions. It also shows how textured human population variation can be in particular circumstances. Genetic diversity within individual Pacific populations is shown to be very low, while differentiation among Melanesian groups is high. Melanesian differentiation varies not only between islands, but also by island size and topographical complexity. The greatest distinctions are among the isolated groups in large island interiors, which are also the most internally homogeneous. The pattern loosely tracks language distinctions. Papuan-speaking groups are the most differentiated, and Austronesian or Oceanic-speaking groups, which tend to live along the coastlines, are more intermixed. A small "Austronesian" genetic signature (always <20%) was detected in less than half the Melanesian groups that speak Austronesian languages, and is entirely lacking in Papuan-speaking groups. Although the Polynesians are also distinctive, they tend to cluster with Micronesians, Taiwan Aborigines, and East Asians, and not Melanesians. These findings contribute to a resolution to the debates over Polynesian origins and their past interactions with Melanesians. With regard to genetics, the earlier studies had heavily relied on the evidence from single locus mitochondrial DNA or Y chromosome variation. Neither of these provided an unequivocal signal of phylogenetic relations or population intermixture proportions in the Pacific. Our analysis indicates the ancestors of Polynesians moved through Melanesia relatively rapidly and only intermixed to a very modest degree with the indigenous populations there.


Asunto(s)
Eliminación de Gen , Marcadores Genéticos , Genética de Población , Geografía , Repeticiones de Microsatélite/genética , Mutagénesis Insercional , Nativos de Hawái y Otras Islas del Pacífico/genética , Alelos , Teorema de Bayes , ADN Mitocondrial/genética , Emigración e Inmigración , Frecuencia de los Genes , Flujo Genético , Ligamiento Genético , Variación Genética , Genoma Humano , Haplotipos , Heterocigoto , Humanos , Lenguaje , Modelos Genéticos , Filogenia , Polimorfismo Genético
18.
Genetics ; 177(4): 2195-207, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18073427

RESUMEN

We estimate parameters of a general isolation-with-migration model using resequence data from mitochondrial DNA (mtDNA), the Y chromosome, and two loci on the X chromosome in samples of 25-50 individuals from each of 10 human populations. Application of a coalescent-based Markov chain Monte Carlo technique allows simultaneous inference of divergence times, rates of gene flow, as well as changes in effective population size. Results from comparisons between sub-Saharan African and Eurasian populations estimate that 1500 individuals founded the ancestral Eurasian population approximately 40 thousand years ago (KYA). Furthermore, these small Eurasian founding populations appear to have grown much more dramatically than either African or Oceanian populations. Analyses of sub-Saharan African populations provide little evidence for a history of population bottlenecks and suggest that they began diverging from one another upward of 50 KYA. We surmise that ancestral African populations had already been geographically structured prior to the founding of ancestral Eurasian populations. African populations are shown to experience low levels of mitochondrial DNA gene flow, but high levels of Y chromosome gene flow. In particular, Y chromosome gene flow appears to be asymmetric, i.e., from the Bantu-speaking population into other African populations. Conversely, mitochondrial gene flow is more extensive between non-African populations, but appears to be absent between European and Asian populations.


Asunto(s)
Cromosomas Humanos X , Cromosomas Humanos Y , ADN Mitocondrial , Flujo Génico , Genética de Población , Dinámica Poblacional , Secuencia de Bases , Humanos , Cadenas de Markov , Densidad de Población , Grupos Raciales/genética
19.
PLoS One ; 2(2): e248, 2007 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-17327912

RESUMEN

Melanesian populations are known for their diversity, but it has been hard to grasp the pattern of the variation or its underlying dynamic. Using 1,223 mitochondrial DNA (mtDNA) sequences from hypervariable regions 1 and 2 (HVR1 and HVR2) from 32 populations, we found the among-group variation is structured by island, island size, and also by language affiliation. The more isolated inland Papuan-speaking groups on the largest islands have the greatest distinctions, while shore dwelling populations are considerably less diverse (at the same time, within-group haplotype diversity is less in the most isolated groups). Persistent differences between shore and inland groups in effective population sizes and marital migration rates probably cause these differences. We also add 16 whole sequences to the Melanesian mtDNA phylogenies. We identify the likely origins of a number of the haplogroups and ancient branches in specific islands, point to some ancient mtDNA connections between Near Oceania and Australia, and show additional Holocene connections between Island Southeast Asia/Taiwan and Island Melanesia with branches of haplogroup E. Coalescence estimates based on synonymous transitions in the coding region suggest an initial settlement and expansion in the region at approximately 30-50,000 years before present (YBP), and a second important expansion from Island Southeast Asia/Taiwan during the interval approximately 3,500-8,000 YBP. However, there are some important variance components in molecular dating that have been overlooked, and the specific nature of ancestral (maternal) Austronesian influence in this region remains unresolved.


Asunto(s)
Población Negra/genética , ADN Mitocondrial/genética , Variación Genética , Secuencia de Bases , Emigración e Inmigración , Etnicidad/genética , Efecto Fundador , Flujo Génico , Haplotipos/genética , Humanos , Melanesia , Datos de Secuencia Molecular , Nativos de Hawái y Otras Islas del Pacífico/genética , Oceanía/etnología , Filogenia , Alineación de Secuencia , Análisis de Secuencia de ADN , Homología de Secuencia de Ácido Nucleico
20.
Mol Biol Evol ; 23(8): 1628-41, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16754639

RESUMEN

To investigate the paternal population history of populations in Northern Island Melanesia, 685 paternally unrelated males from 36 populations in this region and New Guinea were analyzed at 14 regionally informative binary markers and 7 short tandem repeat (STR) loci from the nonrecombining portion of the Y chromosome. Three newly defined binary markers (K6-P79, K7-P117, and M2-P87) aided in identifying considerable heterozygosity that would have otherwise gone undetected. Judging from their geographic distributions and network analyses of their associated STR profiles, 4 lineages appear to have developed in this region and to be of considerable age: K6-P79, K7-P117, M2-P87, and M2a-P22. The origins of K5-M230 and M-M4 are also confirmed as being located further west, probably in New Guinea. In the 25 adequately sampled populations, the number of different haplogroups ranged from 2 in the single most isolated group (the Aita of Bougainville), to 9, and measures of molecular diversity were generally not particularly low. The resulting pattern contradicts earlier findings that suggested far lower male-mediated diversity and gene exchange rates in the region. However, these earlier studies had not included the newly defined haplogroups. We could only identify a very weak signal of recent male Southeast Asian genetic influence (<10%), which was almost entirely restricted to Austronesian (Oceanic)-speaking groups. This contradicts earlier assumptions on the ancestral composition of these groups and requires a revision of hypotheses concerning the settlement of the islands of the central Pacific, which commenced from this region.


Asunto(s)
Cromosomas Humanos Y , Frecuencia de los Genes , Variación Genética , Haplotipos , Repeticiones de Microsatélite , Filogenia , Alelos , Humanos , Masculino , Melanesia , Nueva Guinea , Polimorfismo de Nucleótido Simple
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