RESUMEN
Multiple sclerosis (MS) is a neuro-inflammatory and neurodegenerative disease that is most prevalent in Northern Europe. Although it is known that inherited risk for MS is located within or in close proximity to immune-related genes, it is unknown when, where and how this genetic risk originated1. Here, by using a large ancient genome dataset from the Mesolithic period to the Bronze Age2, along with new Medieval and post-Medieval genomes, we show that the genetic risk for MS rose among pastoralists from the Pontic steppe and was brought into Europe by the Yamnaya-related migration approximately 5,000 years ago. We further show that these MS-associated immunogenetic variants underwent positive selection both within the steppe population and later in Europe, probably driven by pathogenic challenges coinciding with changes in diet, lifestyle and population density. This study highlights the critical importance of the Neolithic period and Bronze Age as determinants of modern immune responses and their subsequent effect on the risk of developing MS in a changing environment.
Asunto(s)
Predisposición Genética a la Enfermedad , Genoma Humano , Pradera , Esclerosis Múltiple , Humanos , Conjuntos de Datos como Asunto , Dieta/etnología , Dieta/historia , Europa (Continente)/etnología , Predisposición Genética a la Enfermedad/historia , Genética Médica , Historia del Siglo XV , Historia Antigua , Historia Medieval , Migración Humana/historia , Estilo de Vida/etnología , Estilo de Vida/historia , Esclerosis Múltiple/genética , Esclerosis Múltiple/historia , Esclerosis Múltiple/inmunología , Enfermedades Neurodegenerativas/genética , Enfermedades Neurodegenerativas/historia , Enfermedades Neurodegenerativas/inmunología , Densidad de PoblaciónRESUMEN
The Holocene (beginning around 12,000 years ago) encompassed some of the most significant changes in human evolution, with far-reaching consequences for the dietary, physical and mental health of present-day populations. Using a dataset of more than 1,600 imputed ancient genomes1, we modelled the selection landscape during the transition from hunting and gathering, to farming and pastoralism across West Eurasia. We identify key selection signals related to metabolism, including that selection at the FADS cluster began earlier than previously reported and that selection near the LCT locus predates the emergence of the lactase persistence allele by thousands of years. We also find strong selection in the HLA region, possibly due to increased exposure to pathogens during the Bronze Age. Using ancient individuals to infer local ancestry tracts in over 400,000 samples from the UK Biobank, we identify widespread differences in the distribution of Mesolithic, Neolithic and Bronze Age ancestries across Eurasia. By calculating ancestry-specific polygenic risk scores, we show that height differences between Northern and Southern Europe are associated with differential Steppe ancestry, rather than selection, and that risk alleles for mood-related phenotypes are enriched for Neolithic farmer ancestry, whereas risk alleles for diabetes and Alzheimer's disease are enriched for Western hunter-gatherer ancestry. Our results indicate that ancient selection and migration were large contributors to the distribution of phenotypic diversity in present-day Europeans.
Asunto(s)
Asiático , Pueblo Europeo , Genoma Humano , Selección Genética , Humanos , Afecto , Agricultura/historia , Alelos , Enfermedad de Alzheimer/genética , Asia/etnología , Asiático/genética , Diabetes Mellitus/genética , Europa (Continente)/etnología , Pueblo Europeo/genética , Agricultores/historia , Sitios Genéticos/genética , Predisposición Genética a la Enfermedad , Genoma Humano/genética , Historia Antigua , Migración Humana , Caza/historia , Familia de Multigenes/genética , Fenotipo , Biobanco del Reino Unido , Herencia Multifactorial/genéticaRESUMEN
BACKGROUND: Inflammatory bowel disease (IBD), Crohn's disease, and ulcerative colitis are chronic autoimmune lifelong diseases with fluctuating activity over time. The treatment includes medical therapy and surgery, however, there is no definite cure. Therefore, the quest for new and supplementary treatment options is imperative to improve patients' general health and quality of life. Physical activity and exercise have been suggested to be elements in both the prevention and supplementary treatment of IBD; however, this is based on limited underpowered trials. Thus, the role of exercise as a treatment option still has to be settled. We aim to investigate the effect of a 12-week exercise intervention in adult patients with moderately active IBD on three categories of outcomes (1) disease-specific health-related quality of life (IBDQ); (2) general health status of the patients, i.e., waist circumference, disease activity by clinical scorings systems (Harvey Bradshaw Index, Simple Clinical Colitis Activity Index), blood pressure, blood lipids, and non-disease specific quality of life (EQ5D) scores; and (3) explorative outcomes on biomarkers (C-reactive protein and fecal calprotectin) plus different biomarkers of immunology (cytokine panel). METHODS: We will apply a superiority design in this open-label randomized clinical trial including 150 patients equally allocated to intervention and usual care. The intervention will be based on a 12-week aerobic exercise program and will include two supervised exercise sessions of 60 min per week, combined with one weekly home training session. We have defined a moderate exercise level as 60-80% of patients' maximum heart rate. The patients in the intervention group will also be offered an online video lesson of 15-25 min on lifestyle guidance, and the same online video lesson will be offered in the comparator group. Questionnaires on quality of life will be forwarded electronically both at inclusion and at the end of the study, and the patients will have blood samples, and fecal samples for calprotectin at baseline, weeks 4 and 8, as well as after 12 weeks (study end). DISCUSSION: This will be a clinical trial investigating the effect of exercise on patients with Crohn's disease and ulcerative colitis. This trial will add to the evidence on the possible effect of exercise and might clarify whether exercise can benefit as a supplementary treatment addendum. Thus, the trial may provide a new patient-active disease management approach. TRIAL REGISTRATION: ClinicalTrials.gov NCT04816812. Date of first registration: March 23, 2021.
Asunto(s)
Colitis Ulcerosa , Enfermedad de Crohn , Enfermedades Inflamatorias del Intestino , Adulto , Humanos , Colitis Ulcerosa/diagnóstico , Colitis Ulcerosa/terapia , Enfermedad de Crohn/diagnóstico , Enfermedad de Crohn/terapia , Calidad de Vida , Enfermedades Inflamatorias del Intestino/diagnóstico , Enfermedades Inflamatorias del Intestino/terapia , Ejercicio Físico , Biomarcadores/metabolismo , Complejo de Antígeno L1 de Leucocito/metabolismoRESUMEN
Background: While osteoporosis is characterized by skeletal fragility due to increased bone turnover and low bone mineral density (BMD), subjects with abdominal obesity and type-2 diabetes have increased risk of bone fractures despite low bone turnover and increased BMD. Diets with increased protein content are reported to increase bone turnover in healthy adults and may be a point of interest in preserving bone strength in subjects with abdominal obesity and/or type-2 diabetes. Methods: We examined the effect of 12-weeks dietary intervention on bone turnover in 64 adults with abdominal obesity using data from the MERITS trial. The trial was a randomized, controlled, double blinded study in which participants were allocated to receive either 60 g/d of whey protein hydrolysate or maltodextrin in combination with either high (30 g/d) or low dietary fiber intake (10 g/d). Primarily, we assessed changes in plasma markers of bone turnover Procollagen type 1 N-terminal propeptide (p1NP), C-terminal telopeptide type-1 collagen (CTX), and parathyroid hormone (PTH) within the four intervention groups. In addition, we measured u-calcium and u-carbamide excretion, 25(OH)D, and BMD by whole body DXA scans. Finally, we compared changes in insulin resistance (Homeostasis-model assessment of insulin resistance, HOMA-IR) with changes in bone turnover markers.The trial was registered at www.clinicaltrials.gov as NCT02931630. Results: Sixty-four subjects were included in the study. We did not find any effect of twelve weeks of high protein or high fiber intake on plasma levels of P1NP or CTX. There was a nonsignificant positive association between protein intake and PTH levels (p=0.06). U-calcium and u-carbamide increased in both protein groups. There was a positive association between change in HOMA-IR and PTH (p=0.042), while changes in P1NP and CTX did not associate to changes in HOMA-IR. Conclusion: Twelve weeks of increased whey protein intake in subjects with abdominal obesity did not affect markers of bone turnover significantly, although tended to increase PTH levels. Dietary fiber intake did not affect bone turnover. We report a positive association between change in HOMA-IR and PTH supporting a hypothesis of insulin resistance as a potential key factor in the expanding field of bone fragility in T2D subjects.
Asunto(s)
Diabetes Mellitus Tipo 2 , Resistencia a la Insulina , Adulto , Biomarcadores , Remodelación Ósea , Calcio/metabolismo , Fibras de la Dieta/farmacología , Humanos , Obesidad , Obesidad Abdominal/complicaciones , Hormona Paratiroidea , Urea/farmacología , Proteína de Suero de Leche/farmacologíaRESUMEN
Between 5,000 and 6,000 years ago, many Neolithic societies declined throughout western Eurasia due to a combination of factors that are still largely debated. Here, we report the discovery and genome reconstruction of Yersinia pestis, the etiological agent of plague, in Neolithic farmers in Sweden, pre-dating and basal to all modern and ancient known strains of this pathogen. We investigated the history of this strain by combining phylogenetic and molecular clock analyses of the bacterial genome, detailed archaeological information, and genomic analyses from infected individuals and hundreds of ancient human samples across Eurasia. These analyses revealed that multiple and independent lineages of Y. pestis branched and expanded across Eurasia during the Neolithic decline, spreading most likely through early trade networks rather than massive human migrations. Our results are consistent with the existence of a prehistoric plague pandemic that likely contributed to the decay of Neolithic populations in Europe.
Asunto(s)
Peste/historia , Yersinia pestis/clasificación , Yersinia pestis/patogenicidad , Evolución Biológica , ADN Bacteriano/genética , Europa (Continente) , Genoma Bacteriano , Historia Antigua , Humanos , Pandemias , FilogeniaRESUMEN
The Yamnaya expansions from the western steppe into Europe and Asia during the Early Bronze Age (~3000 BCE) are believed to have brought with them Indo-European languages and possibly horse husbandry. We analyzed 74 ancient whole-genome sequences from across Inner Asia and Anatolia and show that the Botai people associated with the earliest horse husbandry derived from a hunter-gatherer population deeply diverged from the Yamnaya. Our results also suggest distinct migrations bringing West Eurasian ancestry into South Asia before and after, but not at the time of, Yamnaya culture. We find no evidence of steppe ancestry in Bronze Age Anatolia from when Indo-European languages are attested there. Thus, in contrast to Europe, Early Bronze Age Yamnaya-related migrations had limited direct genetic impact in Asia.
Asunto(s)
Pueblo Asiatico/genética , Domesticación , Flujo Genético , Genoma Humano , Caballos , Migración Humana/historia , Animales , Asia , Cromosomas Humanos Y/genética , ADN Antiguo , ADN Mitocondrial/genética , Europa (Continente) , Pradera , Historia Antigua , Humanos , Lenguaje , Secuenciación Completa del GenomaRESUMEN
The Caribbean was one of the last parts of the Americas to be settled by humans, but how and when the islands were first occupied remains a matter of debate. Ancient DNA can help answering these questions, but the work has been hampered by poor DNA preservation. We report the genome sequence of a 1,000-year-old Lucayan Taino individual recovered from the site of Preacher's Cave in the Bahamas. We sequenced her genome to 12.4-fold coverage and show that she is genetically most closely related to present-day Arawakan speakers from northern South America, suggesting that the ancestors of the Lucayans originated there. Further, we find no evidence for recent inbreeding or isolation in the ancient genome, suggesting that the Lucayans had a relatively large effective population size. Finally, we show that the native American components in some present-day Caribbean genomes are closely related to the ancient Taino, demonstrating an element of continuity between precontact populations and present-day Latino populations in the Caribbean.
Asunto(s)
Indio Americano o Nativo de Alaska/genética , Genoma Humano/genética , Migración Humana/estadística & datos numéricos , Adulto , Arqueología , Bahamas , ADN Antiguo , ADN Mitocondrial/genética , Femenino , Genética de Población , Genómica , Hispánicos o Latinos/genética , Historia Antigua , Migración Humana/historia , Humanos , Masculino , Paleontología , Filogenia , Adulto JovenRESUMEN
Despite broad agreement that the Americas were initially populated via Beringia, the land bridge that connected far northeast Asia with northwestern North America during the Pleistocene epoch, when and how the peopling of the Americas occurred remains unresolved. Analyses of human remains from Late Pleistocene Alaska are important to resolving the timing and dispersal of these populations. The remains of two infants were recovered at Upward Sun River (USR), and have been dated to around 11.5 thousand years ago (ka). Here, by sequencing the USR1 genome to an average coverage of approximately 17 times, we show that USR1 is most closely related to Native Americans, but falls basal to all previously sequenced contemporary and ancient Native Americans. As such, USR1 represents a distinct Ancient Beringian population. Using demographic modelling, we infer that the Ancient Beringian population and ancestors of other Native Americans descended from a single founding population that initially split from East Asians around 36 ± 1.5 ka, with gene flow persisting until around 25 ± 1.1 ka. Gene flow from ancient north Eurasians into all Native Americans took place 25-20 ka, with Ancient Beringians branching off around 22-18.1 ka. Our findings support a long-term genetic structure in ancestral Native Americans, consistent with the Beringian 'standstill model'. We show that the basal northern and southern Native American branches, to which all other Native Americans belong, diverged around 17.5-14.6 ka, and that this probably occurred south of the North American ice sheets. We also show that after 11.5 ka, some of the northern Native American populations received gene flow from a Siberian population most closely related to Koryaks, but not Palaeo-Eskimos, Inuits or Kets, and that Native American gene flow into Inuits was through northern and not southern Native American groups. Our findings further suggest that the far-northern North American presence of northern Native Americans is from a back migration that replaced or absorbed the initial founding population of Ancient Beringians.
Asunto(s)
Efecto Fundador , Genoma Humano/genética , Indígenas Norteamericanos/genética , Modelos Genéticos , Filogenia , Alaska , Asia Oriental/etnología , Flujo Génico , Genética de Población , Historia Antigua , Migración Humana , Humanos , Lactante , Ríos , Siberia/etnología , Factores de TiempoRESUMEN
Present-day hunter-gatherers (HGs) live in multilevel social groups essential to sustain a population structure characterized by limited levels of within-band relatedness and inbreeding. When these wider social networks evolved among HGs is unknown. To investigate whether the contemporary HG strategy was already present in the Upper Paleolithic, we used complete genome sequences from Sunghir, a site dated to ~34,000 years before the present, containing multiple anatomically modern human individuals. We show that individuals at Sunghir derive from a population of small effective size, with limited kinship and levels of inbreeding similar to HG populations. Our findings suggest that Upper Paleolithic social organization was similar to that of living HGs, with limited relatedness within residential groups embedded in a larger mating network.
Asunto(s)
Genoma Humano , Conducta Reproductiva/historia , Conducta Social/historia , ADN Antiguo , Historia Antigua , Humanos , Densidad de Población , Federación de RusiaRESUMEN
FADS genes encode fatty acid desaturases that are important for the conversion of short chain polyunsaturated fatty acids (PUFAs) to long chain fatty acids. Prior studies indicate that the FADS genes have been subjected to strong positive selection in Africa, South Asia, Greenland, and Europe. By comparing FADS sequencing data from present-day and Bronze Age (5-3k years ago) Europeans, we identify possible targets of selection in the European population, which suggest that selection has targeted different alleles in the FADS genes in Europe than it has in South Asia or Greenland. The alleles showing the strongest changes in allele frequency since the Bronze Age show associations with expression changes and multiple lipid-related phenotypes. Furthermore, the selected alleles are associated with a decrease in linoleic acid and an increase in arachidonic and eicosapentaenoic acids among Europeans; this is an opposite effect of that observed for selected alleles in Inuit from Greenland. We show that multiple SNPs in the region affect expression levels and PUFA synthesis. Additionally, we find evidence for a gene-environment interaction influencing low-density lipoprotein (LDL) levels between alleles affecting PUFA synthesis and PUFA dietary intake: carriers of the derived allele display lower LDL cholesterol levels with a higher intake of PUFAs. We hypothesize that the selective patterns observed in Europeans were driven by a change in dietary composition of fatty acids following the transition to agriculture, resulting in a lower intake of arachidonic acid and eicosapentaenoic acid, but a higher intake of linoleic acid and α-linolenic acid.
Asunto(s)
Ácido Graso Desaturasas/genética , Ácidos Grasos/genética , Alelos , ADN Antiguo/análisis , Dieta , Grasas de la Dieta/metabolismo , Evolución Molecular , Ácido Graso Desaturasas/metabolismo , Ácidos Grasos/metabolismo , Ácidos Grasos Insaturados/genética , Frecuencia de los Genes/genética , Interacción Gen-Ambiente , Humanos , Ácido Linoleico/genética , Lípidos/genética , Familia de Multigenes/genética , Fenotipo , Polimorfismo de Nucleótido Simple/genética , Análisis de Secuencia de ADN , Población Blanca/genéticaRESUMEN
During the Last Glacial Maximum, continental ice sheets isolated Beringia (northeast Siberia and northwest North America) from unglaciated North America. By around 15 to 14 thousand calibrated radiocarbon years before present (cal. kyr bp), glacial retreat opened an approximately 1,500-km-long corridor between the ice sheets. It remains unclear when plants and animals colonized this corridor and it became biologically viable for human migration. We obtained radiocarbon dates, pollen, macrofossils and metagenomic DNA from lake sediment cores in a bottleneck portion of the corridor. We find evidence of steppe vegetation, bison and mammoth by approximately 12.6 cal. kyr bp, followed by open forest, with evidence of moose and elk at about 11.5 cal. kyr bp, and boreal forest approximately 10 cal. kyr bp. Our findings reveal that the first Americans, whether Clovis or earlier groups in unglaciated North America before 12.6 cal. kyr bp, are unlikely to have travelled by this route into the Americas. However, later groups may have used this north-south passageway.
Asunto(s)
Migración Animal , Migración Humana/historia , Cubierta de Hielo , Animales , Bison/fisiología , ADN/análisis , Ciervos/fisiología , Bosques , Fósiles , Genómica , Sedimentos Geológicos/química , Historia Antigua , Humanos , Mamuts/fisiología , Modelos Teóricos , América del Norte , Polen , Datación Radiométrica , SiberiaRESUMEN
The bacteria Yersinia pestis is the etiological agent of plague and has caused human pandemics with millions of deaths in historic times. How and when it originated remains contentious. Here, we report the oldest direct evidence of Yersinia pestis identified by ancient DNA in human teeth from Asia and Europe dating from 2,800 to 5,000 years ago. By sequencing the genomes, we find that these ancient plague strains are basal to all known Yersinia pestis. We find the origins of the Yersinia pestis lineage to be at least two times older than previous estimates. We also identify a temporal sequence of genetic changes that lead to increased virulence and the emergence of the bubonic plague. Our results show that plague infection was endemic in the human populations of Eurasia at least 3,000 years before any historical recordings of pandemics.
Asunto(s)
Peste/microbiología , Yersinia pestis/clasificación , Yersinia pestis/aislamiento & purificación , Animales , Asia , ADN Bacteriano/genética , Europa (Continente) , Historia Antigua , Historia Medieval , Humanos , Peste/historia , Peste/transmisión , Siphonaptera/microbiología , Diente/microbiología , Yersinia pestis/genéticaRESUMEN
The indigenous people of Greenland, the Inuit, have lived for a long time in the extreme conditions of the Arctic, including low annual temperatures, and with a specialized diet rich in protein and fatty acids, particularly omega-3 polyunsaturated fatty acids (PUFAs). A scan of Inuit genomes for signatures of adaptation revealed signals at several loci, with the strongest signal located in a cluster of fatty acid desaturases that determine PUFA levels. The selected alleles are associated with multiple metabolic and anthropometric phenotypes and have large effect sizes for weight and height, with the effect on height replicated in Europeans. By analyzing membrane lipids, we found that the selected alleles modulate fatty acid composition, which may affect the regulation of growth hormones. Thus, the Inuit have genetic and physiological adaptations to a diet rich in PUFAs.
Asunto(s)
Aclimatación/genética , Dieta Alta en Grasa , Ácidos Grasos Omega-3/administración & dosificación , Inuk/genética , Alelos , Regiones Árticas , Estatura/genética , Peso Corporal/genética , Cromosomas Humanos Par 11/genética , Clima , Ácidos Grasos Omega-3/análisis , Femenino , Sitios Genéticos , Genoma Humano/genética , Estudio de Asociación del Genoma Completo , Groenlandia , Humanos , Desequilibrio de Ligamiento , Masculino , Lípidos de la Membrana/análisis , Lípidos de la Membrana/genética , Polimorfismo de Nucleótido Simple , Selección GenéticaRESUMEN
The origin of contemporary Europeans remains contentious. We obtained a genome sequence from Kostenki 14 in European Russia dating from 38,700 to 36,200 years ago, one of the oldest fossils of anatomically modern humans from Europe. We find that Kostenki 14 shares a close ancestry with the 24,000-year-old Mal'ta boy from central Siberia, European Mesolithic hunter-gatherers, some contemporary western Siberians, and many Europeans, but not eastern Asians. Additionally, the Kostenki 14 genome shows evidence of shared ancestry with a population basal to all Eurasians that also relates to later European Neolithic farmers. We find that Kostenki 14 contains more Neandertal DNA that is contained in longer tracts than present Europeans. Our findings reveal the timing of divergence of western Eurasians and East Asians to be more than 36,200 years ago and that European genomic structure today dates back to the Upper Paleolithic and derives from a metapopulation that at times stretched from Europe to central Asia.
Asunto(s)
ADN/genética , Genoma Humano/genética , Población Blanca/genética , ADN/historia , Europa (Continente) , Fósiles , Genómica , Historia Antigua , Humanos , Masculino , Siberia , Población Blanca/historiaRESUMEN
Clovis, with its distinctive biface, blade and osseous technologies, is the oldest widespread archaeological complex defined in North America, dating from 11,100 to 10,700 (14)C years before present (bp) (13,000 to 12,600 calendar years bp). Nearly 50 years of archaeological research point to the Clovis complex as having developed south of the North American ice sheets from an ancestral technology. However, both the origins and the genetic legacy of the people who manufactured Clovis tools remain under debate. It is generally believed that these people ultimately derived from Asia and were directly related to contemporary Native Americans. An alternative, Solutrean, hypothesis posits that the Clovis predecessors emigrated from southwestern Europe during the Last Glacial Maximum. Here we report the genome sequence of a male infant (Anzick-1) recovered from the Anzick burial site in western Montana. The human bones date to 10,705 ± 35 (14)C years bp (approximately 12,707-12,556 calendar years bp) and were directly associated with Clovis tools. We sequenced the genome to an average depth of 14.4× and show that the gene flow from the Siberian Upper Palaeolithic Mal'ta population into Native American ancestors is also shared by the Anzick-1 individual and thus happened before 12,600 years bp. We also show that the Anzick-1 individual is more closely related to all indigenous American populations than to any other group. Our data are compatible with the hypothesis that Anzick-1 belonged to a population directly ancestral to many contemporary Native Americans. Finally, we find evidence of a deep divergence in Native American populations that predates the Anzick-1 individual.
Asunto(s)
Genoma Humano/genética , Indígenas Norteamericanos/genética , Filogenia , Arqueología , Asia/etnología , Huesos , Entierro , Cromosomas Humanos Y/genética , ADN Mitocondrial/genética , Emigración e Inmigración/historia , Europa (Continente)/etnología , Flujo Génico/genética , Haplotipos/genética , Historia Antigua , Humanos , Lactante , Masculino , Modelos Genéticos , Datos de Secuencia Molecular , Montana , Dinámica Poblacional , Datación RadiométricaRESUMEN
Ancient genomic sequences have started to reveal the origin and the demographic impact of farmers from the Neolithic period spreading into Europe. The adoption of farming, stock breeding and sedentary societies during the Neolithic may have resulted in adaptive changes in genes associated with immunity and diet. However, the limited data available from earlier hunter-gatherers preclude an understanding of the selective processes associated with this crucial transition to agriculture in recent human evolution. Here we sequence an approximately 7,000-year-old Mesolithic skeleton discovered at the La Braña-Arintero site in León, Spain, to retrieve a complete pre-agricultural European human genome. Analysis of this genome in the context of other ancient samples suggests the existence of a common ancient genomic signature across western and central Eurasia from the Upper Paleolithic to the Mesolithic. The La Braña individual carries ancestral alleles in several skin pigmentation genes, suggesting that the light skin of modern Europeans was not yet ubiquitous in Mesolithic times. Moreover, we provide evidence that a significant number of derived, putatively adaptive variants associated with pathogen resistance in modern Europeans were already present in this hunter-gatherer.
Asunto(s)
Alelos , Fósiles , Inmunidad/genética , Pigmentación/genética , Población Blanca/genética , Agricultura/historia , Evolución Biológica , Cuevas , Color del Ojo/genética , Genoma Humano/genética , Genómica , Historia Antigua , Humanos , Intolerancia a la Lactosa/genética , Masculino , Polimorfismo de Nucleótido Simple/genética , Análisis de Componente Principal , Esqueleto , Pigmentación de la Piel/genética , España/etnologíaRESUMEN
Despite decades of research, the roles of climate and humans in driving the dramatic extinctions of large-bodied mammals during the Late Quaternary period remain contentious. Here we use ancient DNA, species distribution models and the human fossil record to elucidate how climate and humans shaped the demographic history of woolly rhinoceros, woolly mammoth, wild horse, reindeer, bison and musk ox. We show that climate has been a major driver of population change over the past 50,000 years. However, each species responds differently to the effects of climatic shifts, habitat redistribution and human encroachment. Although climate change alone can explain the extinction of some species, such as Eurasian musk ox and woolly rhinoceros, a combination of climatic and anthropogenic effects appears to be responsible for the extinction of others, including Eurasian steppe bison and wild horse. We find no genetic signature or any distinctive range dynamics distinguishing extinct from surviving species, emphasizing the challenges associated with predicting future responses of extant mammals to climate and human-mediated habitat change.
Asunto(s)
Biota , Cambio Climático/historia , Extinción Biológica , Actividades Humanas/historia , Mamíferos/fisiología , Animales , Teorema de Bayes , Bison , ADN Mitocondrial/análisis , ADN Mitocondrial/genética , Europa (Continente) , Fósiles , Variación Genética , Geografía , Historia Antigua , Caballos , Humanos , Mamíferos/genética , Mamuts , Datos de Secuencia Molecular , Dinámica Poblacional , Reno , Siberia , Especificidad de la Especie , Factores de TiempoRESUMEN
We report here the genome sequence of an ancient human. Obtained from approximately 4,000-year-old permafrost-preserved hair, the genome represents a male individual from the first known culture to settle in Greenland. Sequenced to an average depth of 20x, we recover 79% of the diploid genome, an amount close to the practical limit of current sequencing technologies. We identify 353,151 high-confidence single-nucleotide polymorphisms (SNPs), of which 6.8% have not been reported previously. We estimate raw read contamination to be no higher than 0.8%. We use functional SNP assessment to assign possible phenotypic characteristics of the individual that belonged to a culture whose location has yielded only trace human remains. We compare the high-confidence SNPs to those of contemporary populations to find the populations most closely related to the individual. This provides evidence for a migration from Siberia into the New World some 5,500 years ago, independent of that giving rise to the modern Native Americans and Inuit.
Asunto(s)
Criopreservación , Extinción Biológica , Genoma Humano/genética , Inuk/genética , Emigración e Inmigración/historia , Genética de Población , Genómica , Genotipo , Groenlandia , Cabello , Historia Antigua , Humanos , Masculino , Fenotipo , Filogenia , Polimorfismo de Nucleótido Simple/genética , Análisis de Secuencia de ADN , Siberia/etnologíaRESUMEN
It is difficult to obtain fossil data from the 10% of Earth's terrestrial surface that is covered by thick glaciers and ice sheets, and hence, knowledge of the paleoenvironments of these regions has remained limited. We show that DNA and amino acids from buried organisms can be recovered from the basal sections of deep ice cores, enabling reconstructions of past flora and fauna. We show that high-altitude southern Greenland, currently lying below more than 2 kilometers of ice, was inhabited by a diverse array of conifer trees and insects within the past million years. The results provide direct evidence in support of a forested southern Greenland and suggest that many deep ice cores may contain genetic records of paleoenvironments in their basal sections.