Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Science ; 369(6511): 1653-1656, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32973032

RESUMO

Ancient DNA has provided new insights into many aspects of human history. However, we lack comprehensive studies of the Y chromosomes of Denisovans and Neanderthals because the majority of specimens that have been sequenced to sufficient coverage are female. Sequencing Y chromosomes from two Denisovans and three Neanderthals shows that the Y chromosomes of Denisovans split around 700 thousand years ago from a lineage shared by Neanderthals and modern human Y chromosomes, which diverged from each other around 370 thousand years ago. The phylogenetic relationships of archaic and modern human Y chromosomes differ from the population relationships inferred from the autosomal genomes and mirror mitochondrial DNA phylogenies, indicating replacement of both the mitochondrial and Y chromosomal gene pools in late Neanderthals. This replacement is plausible if the low effective population size of Neanderthals resulted in an increased genetic load in Neanderthals relative to modern humans.


Assuntos
Evolução Molecular , Características de História de Vida , Homem de Neandertal/genética , Cromossomo Y/genética , Animais , Cromossomos Humanos Y/genética , DNA Antigo , DNA Mitocondrial/genética , Humanos , Masculino , Homem de Neandertal/classificação , Filogenia
2.
Proc Natl Acad Sci U S A ; 111(18): 6666-71, 2014 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-24753607

RESUMO

We present the DNA sequence of 17,367 protein-coding genes in two Neandertals from Spain and Croatia and analyze them together with the genome sequence recently determined from a Neandertal from southern Siberia. Comparisons with present-day humans from Africa, Europe, and Asia reveal that genetic diversity among Neandertals was remarkably low, and that they carried a higher proportion of amino acid-changing (nonsynonymous) alleles inferred to alter protein structure or function than present-day humans. Thus, Neandertals across Eurasia had a smaller long-term effective population than present-day humans. We also identify amino acid substitutions in Neandertals and present-day humans that may underlie phenotypic differences between the two groups. We find that genes involved in skeletal morphology have changed more in the lineage leading to Neandertals than in the ancestral lineage common to archaic and modern humans, whereas genes involved in behavior and pigmentation have changed more on the modern human lineage.


Assuntos
Exoma , Variação Genética , Homem de Neandertal/genética , Substituição de Aminoácidos , Animais , Croácia , DNA/genética , Frequência do Gene , Humanos , Paleontologia , Filogenia , Polimorfismo de Nucleotídeo Único , Sibéria , Espanha
3.
Proc Natl Acad Sci U S A ; 111(6): 2229-34, 2014 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-24469802

RESUMO

One of the main impediments for obtaining DNA sequences from ancient human skeletons is the presence of contaminating modern human DNA molecules in many fossil samples and laboratory reagents. However, DNA fragments isolated from ancient specimens show a characteristic DNA damage pattern caused by miscoding lesions that differs from present day DNA sequences. Here, we develop a framework for evaluating the likelihood of a sequence originating from a model with postmortem degradation-summarized in a postmortem degradation score-which allows the identification of DNA fragments that are unlikely to originate from present day sources. We apply this approach to a contaminated Neandertal specimen from Okladnikov Cave in Siberia to isolate its endogenous DNA from modern human contaminants and show that the reconstructed mitochondrial genome sequence is more closely related to the variation of Western Neandertals than what was discernible from previous analyses. Our method opens up the potential for genomic analysis of contaminated fossil material.


Assuntos
DNA Mitocondrial/isolamento & purificação , Homem de Neandertal/genética , Animais , DNA Mitocondrial/genética , Humanos , Dados de Sequência Molecular , Sibéria
4.
Nature ; 505(7481): 43-9, 2014 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-24352235

RESUMO

We present a high-quality genome sequence of a Neanderthal woman from Siberia. We show that her parents were related at the level of half-siblings and that mating among close relatives was common among her recent ancestors. We also sequenced the genome of a Neanderthal from the Caucasus to low coverage. An analysis of the relationships and population history of available archaic genomes and 25 present-day human genomes shows that several gene flow events occurred among Neanderthals, Denisovans and early modern humans, possibly including gene flow into Denisovans from an unknown archaic group. Thus, interbreeding, albeit of low magnitude, occurred among many hominin groups in the Late Pleistocene. In addition, the high-quality Neanderthal genome allows us to establish a definitive list of substitutions that became fixed in modern humans after their separation from the ancestors of Neanderthals and Denisovans.


Assuntos
Fósseis , Genoma/genética , Homem de Neandertal/genética , África , Animais , Cavernas , Variações do Número de Cópias de DNA/genética , Feminino , Fluxo Gênico/genética , Frequência do Gene , Heterozigoto , Humanos , Endogamia , Modelos Genéticos , Homem de Neandertal/classificação , Filogenia , Densidade Demográfica , Sibéria/etnologia , Falanges dos Dedos do Pé/anatomia & histologia
5.
Science ; 338(6104): 222-6, 2012 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-22936568

RESUMO

We present a DNA library preparation method that has allowed us to reconstruct a high-coverage (30×) genome sequence of a Denisovan, an extinct relative of Neandertals. The quality of this genome allows a direct estimation of Denisovan heterozygosity indicating that genetic diversity in these archaic hominins was extremely low. It also allows tentative dating of the specimen on the basis of "missing evolution" in its genome, detailed measurements of Denisovan and Neandertal admixture into present-day human populations, and the generation of a near-complete catalog of genetic changes that swept to high frequency in modern humans since their divergence from Denisovans.


Assuntos
Variação Genética , Genoma Humano/genética , Heterozigoto , Homem de Neandertal/genética , Alelos , Animais , Sequência de Bases , Fósseis , Fluxo Gênico , Biblioteca Gênica , Humanos , Dados de Sequência Molecular , Análise de Sequência de DNA
6.
Nature ; 468(7327): 1053-60, 2010 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-21179161

RESUMO

Using DNA extracted from a finger bone found in Denisova Cave in southern Siberia, we have sequenced the genome of an archaic hominin to about 1.9-fold coverage. This individual is from a group that shares a common origin with Neanderthals. This population was not involved in the putative gene flow from Neanderthals into Eurasians; however, the data suggest that it contributed 4-6% of its genetic material to the genomes of present-day Melanesians. We designate this hominin population 'Denisovans' and suggest that it may have been widespread in Asia during the Late Pleistocene epoch. A tooth found in Denisova Cave carries a mitochondrial genome highly similar to that of the finger bone. This tooth shares no derived morphological features with Neanderthals or modern humans, further indicating that Denisovans have an evolutionary history distinct from Neanderthals and modern humans.


Assuntos
Fósseis , Fluxo Gênico , Genoma/genética , Hominidae/classificação , Hominidae/genética , Animais , Ásia , DNA Mitocondrial/genética , Europa (Continente) , Falanges dos Dedos da Mão/química , Humanos , Melanesia , Dados de Sequência Molecular , Filogenia , Sibéria , Dente/anatomia & histologia , Dente/química
7.
Nature ; 464(7290): 894-7, 2010 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-20336068

RESUMO

With the exception of Neanderthals, from which DNA sequences of numerous individuals have now been determined, the number and genetic relationships of other hominin lineages are largely unknown. Here we report a complete mitochondrial (mt) DNA sequence retrieved from a bone excavated in 2008 in Denisova Cave in the Altai Mountains in southern Siberia. It represents a hitherto unknown type of hominin mtDNA that shares a common ancestor with anatomically modern human and Neanderthal mtDNAs about 1.0 million years ago. This indicates that it derives from a hominin migration out of Africa distinct from that of the ancestors of Neanderthals and of modern humans. The stratigraphy of the cave where the bone was found suggests that the Denisova hominin lived close in time and space with Neanderthals as well as with modern humans.


Assuntos
DNA Mitocondrial/genética , Genoma Mitocondrial/genética , Hominidae/classificação , Hominidae/genética , Filogenia , África/etnologia , Animais , DNA Mitocondrial/isolamento & purificação , Emigração e Imigração , Extinção Biológica , Falanges dos Dedos da Mão , Humanos , Dados de Sequência Molecular , Alinhamento de Sequência , Sibéria , Fatores de Tempo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...