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1.
Proc Natl Acad Sci U S A ; 121(36): e2317868121, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39159385

RESUMO

Elites played a pivotal role in the formation of post-Roman Europe on both macro- and microlevels during the Early Medieval period. History and archaeology have long focused on their description and identification based on written sources or through their archaeological record. We provide a different perspective on this topic by integrating paleogenomic, archaeological, and isotopic data to gain insights into the role of one such elite group in a Langobard period community near Collegno, Italy dated to the 6-8th centuries CE. Our analysis of 28 newly sequenced genomes together with 24 previously published ones combined with isotope (Sr, C, N) measurements revealed that this community was established by and organized around a network of biologically and socially related individuals likely composed of multiple elite families that over time developed into a single extended pedigree. The community also included individuals with diverse genetic ancestries, maintaining its diversity by integrating newcomers and groups in later stages of its existence. This study highlights how shifts in political power and migration impacted the formation and development of a small rural community within a key region of the former Western Roman Empire after its dissolution and the emergence of a new kingdom. Furthermore, it suggests that Early Medieval elites had the capacity to incorporate individuals from varied backgrounds and that these elites were the result of (political) agency rather than belonging to biologically homogeneous groups.


Assuntos
Arqueologia , Mundo Romano , Humanos , Mundo Romano/história , Itália , História Medieval , Migração Humana/história , História Antiga
2.
Proc Natl Acad Sci U S A ; 121(34): e2405993121, 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39136992

RESUMO

Beluga whales play a critical role in the subsistence economies and cultural heritage of Indigenous communities across the Arctic, yet the effects of Indigenous hunting on beluga whales remain unknown. Here, we integrate paleogenomics, genetic simulations, and stable δ13C and δ15N isotope analysis to investigate 700 y of beluga subsistence hunting in the Mackenzie Delta area of northwestern Canada. Genetic identification of the zooarchaeological remains, which is based on radiocarbon dating, span three time periods (1290 to 1440 CE; 1450 to 1650 CE; 1800 to 1870 CE), indicates shifts across time in the sex ratio of the harvested belugas. The equal number of females and males harvested in 1450 to 1650 CE versus more males harvested in the two other time periods may reflect changes in hunting practices or temporal shifts in beluga availability. We find temporal shifts and sex-based differences in δ13C of the harvested belugas across time, suggesting historical adaptability in the foraging ecology of the whales. We uncovered distinct mitochondrial diversity unique to the Mackenzie Delta belugas, but found no changes in nuclear genomic diversity nor any substructuring across time. Our findings indicate the genomic stability and continuity of the Mackenzie Delta beluga population across the 700 y surveyed, indicating the impact of Inuvialuit subsistence harvests on the genetic diversity of contemporary beluga individuals has been negligible.


Assuntos
Beluga , Animais , Beluga/genética , Territórios do Noroeste , Feminino , Masculino , Caça , Isótopos de Nitrogênio/análise , Isótopos de Carbono/análise , DNA Mitocondrial/genética , Inuíte
3.
Genetics ; 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39013011

RESUMO

Our knowledge of human evolutionary history has been greatly advanced by paleogenomics. Since the 2020s, the study of ancient DNA has increasingly focused on reconstructing the recent past. However, the accuracy of paleogenomic methods in resolving questions of historical and archaeological importance amidst the increased demographic complexity and decreased genetic differentiation remains an open question. We evaluated the performance and behavior of two commonly used methods, qpAdm and the f3-statistic, on admixture inference under a diversity of demographic models and data conditions. We performed two complementary simulation approaches - firstly exploring a wide demographic parameter space under four simple demographic models of varying complexities and configurations using branch-length data from two chromosomes - and secondly, we analyzed a model of Eurasian history composed of 59 populations using whole-genome data modified with ancient DNA conditions such as SNP ascertainment, data missingness, and pseudo-haploidization. We observe population differentiation is the primary factor driving qpAdm performance. Notably, whilst complex gene-flow histories influence which models are classified as plausible, they do not reduce overall performance. Under conditions reflective of the historical period, qpAdm most frequently identifies the true model as plausible amongst a small candidate set of closely related populations. To increase the utility for resolving fine-scaled hypotheses, we provide a heuristic for further distinguishing between candidate models that incorporates qpAdm model P-values and f3-statistics. Finally, we demonstrate a significant performance increase for qpAdm using whole-genome branch-length f2-statistics, highlighting the potential for improved demographic inference that could be achieved with future advancements in f-statistic estimations.

4.
Artigo em Inglês | MEDLINE | ID: mdl-38881417

RESUMO

Using the examples of plague, smallpox, and HIV/AIDS, the present essay argues for the benefits of incorporating the evolutionary histories of pathogens, beyond visible epidemic spikes within human populations, into our understanding of what pandemics actually are as epidemiological phenomena. The pandemic arc - which takes the pathogen as the defining "actor" in a pandemic, from emergence to local proliferation to globalization - offers a framework capable of bringing together disparate aspects not only of the manifestations of disease but also of human involvement in the pandemic process. Pathogens may differ, but there are common patterns in disease emergence and proliferation that distinguish those diseases that become pandemic, dispersed through human communities regionally or globally. The same methods of genomic analysis that allow tracking the evolutionary development of a modern pathogen such as SARS-CoV-2 also allow us to trace pandemics into the past. Reconstruction of these pandemic arcs brings new elements of these stories into view, recovering the experiences of regions and populations hitherto overlooked by Eurocentric narratives. This expanded global history of infectious diseases, in turn, lays a groundwork for reconceiving what ambitions a truly global health might aim for.

5.
Cell ; 187(14): 3531-3540.e13, 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-38942016

RESUMO

A number of species have recently recovered from near-extinction. Although these species have avoided the immediate extinction threat, their long-term viability remains precarious due to the potential genetic consequences of population declines, which are poorly understood on a timescale beyond a few generations. Woolly mammoths (Mammuthus primigenius) became isolated on Wrangel Island around 10,000 years ago and persisted for over 200 generations before becoming extinct around 4,000 years ago. To study the evolutionary processes leading up to the mammoths' extinction, we analyzed 21 Siberian woolly mammoth genomes. Our results show that the population recovered quickly from a severe bottleneck and remained demographically stable during the ensuing six millennia. We find that mildly deleterious mutations gradually accumulated, whereas highly deleterious mutations were purged, suggesting ongoing inbreeding depression that lasted for hundreds of generations. The time-lag between demographic and genetic recovery has wide-ranging implications for conservation management of recently bottlenecked populations.


Assuntos
Extinção Biológica , Genoma , Mamutes , Mutação , Animais , Mamutes/genética , Genoma/genética , Sibéria , Filogenia , Evolução Molecular , Fatores de Tempo
6.
Curr Biol ; 34(9): 2020-2029.e6, 2024 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-38614080

RESUMO

Low genomic diversity is generally indicative of small population size and is considered detrimental by decreasing long-term adaptability.1,2,3,4,5,6 Moreover, small population size may promote gene flow with congeners and outbreeding depression.7,8,9,10,11,12,13 Here, we examine the connection between habitat availability, effective population size (Ne), and extinction by generating a 40× nuclear genome from the extinct blue antelope (Hippotragus leucophaeus). Historically endemic to the relatively small Cape Floristic Region in southernmost Africa,14,15 populations were thought to have expanded and contracted across glacial-interglacial cycles, tracking suitable habitat.16,17,18 However, we found long-term low Ne, unaffected by glacial cycles, suggesting persistence with low genomic diversity for many millennia prior to extinction in ∼AD 1800. A lack of inbreeding, alongside high levels of genetic purging, suggests adaptation to this long-term low Ne and that human impacts during the colonial era (e.g., hunting and landscape transformation), rather than longer-term ecological processes, were central to its extinction. Phylogenomic analyses uncovered gene flow between roan (H. equinus) and blue antelope, as well as between roan and sable antelope (H. niger), approximately at the time of divergence of blue and sable antelope (∼1.9 Ma). Finally, we identified the LYST and ASIP genes as candidates for the eponymous bluish pelt color of the blue antelope. Our results revise numerous aspects of our understanding of the interplay between genomic diversity and evolutionary history and provide the resources for uncovering the genetic basis of this extinct species' unique traits.


Assuntos
Antílopes , Extinção Biológica , Densidade Demográfica , Animais , Antílopes/genética , Antílopes/fisiologia , Variação Genética , Fluxo Gênico , Adaptação Fisiológica/genética , Ecossistema , Genoma
7.
Microbiome ; 11(1): 243, 2023 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-37926832

RESUMO

BACKGROUND: The analysis of ancient oral metagenomes from archaeological human and animal samples is largely confounded by contaminant DNA sequences from modern and environmental sources. Existing methods for Microbial Source Tracking (MST) estimate the proportions of environmental sources, but do not perform well on ancient metagenomes. We developed a novel method called decOM for Microbial Source Tracking and classification of ancient and modern metagenomic samples using k-mer matrices. RESULTS: We analysed a collection of 360 ancient oral, modern oral, sediment/soil and skin metagenomes, using stratified five-fold cross-validation. decOM estimates the contributions of these source environments in ancient oral metagenomic samples with high accuracy, outperforming two state-of-the-art methods for source tracking, FEAST and mSourceTracker. CONCLUSIONS: decOM is a high-accuracy microbial source tracking method, suitable for ancient oral metagenomic data sets. The decOM method is generic and could also be adapted for MST of other ancient and modern types of metagenomes. We anticipate that decOM will be a valuable tool for MST of ancient metagenomic studies. Video Abstract.


Assuntos
Metagenoma , Metagenômica , Animais , Humanos , Metagenômica/métodos
8.
bioRxiv ; 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-38014190

RESUMO

Paleogenomics has expanded our knowledge of human evolutionary history. Since the 2020s, the study of ancient DNA has increased its focus on reconstructing the recent past. However, the accuracy of paleogenomic methods in answering questions of historical and archaeological importance amidst the increased demographic complexity and decreased genetic differentiation within the historical period remains an open question. We used two simulation approaches to evaluate the limitations and behavior of commonly used methods, qpAdm and the f3-statistic, on admixture inference. The first is based on branch-length data simulated from four simple demographic models of varying complexities and configurations. The second, an analysis of Eurasian history composed of 59 populations using whole-genome data modified with ancient DNA conditions such as SNP ascertainment, data missingness, and pseudo-haploidization. We show that under conditions resembling historical populations, qpAdm can identify a small candidate set of true sources and populations closely related to them. However, in typical ancient DNA conditions, qpAdm is unable to further distinguish between them, limiting its utility for resolving fine-scaled hypotheses. Notably, we find that complex gene-flow histories generally lead to improvements in the performance of qpAdm and observe no bias in the estimation of admixture weights. We offer a heuristic for admixture inference that incorporates admixture weight estimate and P-values of qpAdm models, and f3-statistics to enhance the power to distinguish between multiple plausible candidates. Finally, we highlight the future potential of qpAdm through whole-genome branch-length f2-statistics, demonstrating the improved demographic inference that could be achieved with advancements in f-statistic estimations.

9.
Curr Biol ; 33(18): 3951-3961.e11, 2023 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-37633281

RESUMO

As the collapse of the Western Roman Empire accelerated during the 4th and 5th centuries, arriving "barbarian" groups began to establish new communities in the border provinces of the declining (and eventually former) empire. This was a time of significant cultural and political change throughout not only these border regions but Europe as a whole.1,2 To better understand post-Roman community formation in one of these key frontier zones after the collapse of the Hunnic movement, we generated new paleogenomic data for a set of 38 burials from a time series of three 5th century cemeteries3,4,5 at Lake Balaton, Hungary. We utilized a comprehensive sampling approach to characterize these cemeteries along with data from 38 additional burials from a previously published mid-6th century site6 and analyzed them alongside data from over 550 penecontemporaneous individuals.7,8,9,10,11,12,13,14,15,16,17,18,19 The range of genetic diversity in all four of these local burial communities is extensive and wider ranging than penecontemporaneous Europeans sequenced to date. Despite many commonalities in burial customs and demography, we find that there were substantial differences in genetic ancestry between the sites. We detect evidence of northern European gene flow into the Lake Balaton region. Additionally, we observe a statistically significant association between dress artifacts and genetic ancestry among 5th century genetically female burials. Our analysis shows that the formation of early Medieval communities was a multifarious process even at a local level, consisting of genetically heterogeneous groups.


Assuntos
Arqueologia , Cemitérios , Humanos , Feminino , Cemitérios/história , Cultura , Sequência de Bases , Europa (Continente)
10.
Future Microbiol ; 18: 681-693, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37584528

RESUMO

The analysis of past epidemics and pandemics, either spontaneous or of human origin, may revise the physical history of microbiota and create a temporal context in our understanding regarding pathogen attributes like virulence, evolution, transmission and disease dynamics. The data of high-tech scientific methods seem reliable, but their interpretation may still be biased when tackling events of the distant past. Such endeavors should be adjusted to other cognitive resources including historical accounts reporting the events of interest and references in alien medical cultures and terminologies; the latter may contextualize them differently from current practices. Thus 'historical microbiology' emerges. Validating such resources requires utmost care, as these may be susceptible to different biases regarding the interpretation of facts and phenomena; biases partly due to methodological limitations.


Bacteria and viruses have always impacted humankind. They do this directly by causing illness or indirectly by destroying crops and threatening livestock. We can learn a lot by studying disease events of the past ­ for example, we can see how bacteria and viruses have changed over time and predict how they might change in the future. This knowledge could be important to understanding present disease events and predicting future ones. In this review, we propose the concept of 'historical microbiology', which encourages collaboration between scientists, doctors, historians and linguists to provide historical, linguistic and cultural context to our scientific understanding of diseases of the past.


Assuntos
Bolsas de Estudo , Paleopatologia , Humanos , Paleopatologia/métodos , Pandemias
11.
Vavilovskii Zhurnal Genet Selektsii ; 27(4): 373-382, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37465192

RESUMO

The results of studies in Quaternary geology, archeology, paleoanthropology and human genetics demonstrate that the ancestors of Native Americans arrived in mid-latitude North America mainly along the Pacific Northwest Coast, but had previously inhabited the Arctic and during the last glacial maximum were in a refugium in Beringia, a land bridge connecting Eurasia and North America. The gene pool of Native Americans is represented by unique haplogroups of mitochondrial DNA and the Y chromosome, the evolutionary age of which ranges from 13 to 22 thousand years. The results of a paleogenomic analysis also show that during the last glacial maximum Beringia was populated by human groups that had arisen as a result of interaction between the most ancient Upper Paleolithic populations of Northern Eurasia and newcomer groups from East Asia. Approximately 20 thousand years ago the Beringian populations began to form, and the duration of their existence in relative isolation is estimated at about 5 thousand years. Thus, the adaptation of the Beringians to the Arctic conditions could have taken several millennia. The adaptation of Amerindian ancestors to high latitudes and cold climates is supported by genomic data showing that adaptive genetic variants in Native Americans are associated with various metabolic pathways: melanin production processes in the skin, hair and eyes, the functioning of the cardiovascular system, energy metabolism and immune response characteristics. Meanwhile, the analysis of the existing hypotheses about the selection of some genetic variants in the Beringian ancestors of the Amerindians in connection with adaptation to the Arctic conditions (for example, in the FADS, ACTN3, EDAR genes) shows the ambiguity of the testing results, which may be due to the loss of some traces of the "Beringian" adaptation in the gene pools of modern Native Americans. The most optimal strategy for further research seems to be the search for adaptive variant.

12.
Annu Rev Virol ; 10(1): 49-75, 2023 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-37268008

RESUMO

Humans have battled viruses for millennia. However, directly linking the symptomatology of disease outbreaks to specific viral pathogens was not possible until the twentieth century. With the advent of the genomic era and the development of advanced protocols for isolation, sequencing, and analysis of ancient nucleic acids from diverse human remains, the identification and characterization of ancient viruses became feasible. Recent studies have provided invaluable information about past epidemics and made it possible to examine assumptions and inferences on the origin and evolution of certain viral families. In parallel, the study of ancient viruses also uncovered their importance in the evolution of the human lineage and their key roles in shaping major events in human history. In this review, we describe the strategies used for the study of ancient viruses, along with their limitations, and provide a detailed account of what past viral infections have revealed about human history.


Assuntos
Viroses , Vírus , Humanos , Genômica , Viroses/genética , Vírus/genética , Surtos de Doenças , Genoma Viral
13.
Curr Biol ; 33(11): 2350-2358.e7, 2023 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-37207647

RESUMO

The 17th-century colonization of North America brought thousands of Europeans to Indigenous lands in the Delaware region, which comprises the eastern boundary of the Chesapeake Bay in what is now the Mid-Atlantic region of the United States.1 The demographic features of these initial colonial migrations are not uniformly characterized, with Europeans and European-Americans migrating to the Delaware area from other countries and neighboring colonies as single persons or in family units of free persons, indentured servants, or tenant farmers.2 European colonizers also instituted a system of racialized slavery through which they forcibly transported thousands of Africans to the Chesapeake region. Historical information about African-descended individuals in the Delaware region is limited, with a population estimate of less than 500 persons by 1700 CE.3,4 To shed light on the population histories of this period, we analyzed low-coverage genomes of 11 individuals from the Avery's Rest archaeological site (circa 1675-1725 CE), located in Delaware. Previous osteological and mitochondrial DNA (mtDNA) sequence analyses showed a southern group of eight individuals of European maternal descent, buried 15-20 feet from a northern group of three individuals of African maternal descent.5 Autosomal results further illuminate genomic similarities to Northwestern European reference populations or West and West-Central African reference populations, respectively. We also identify three generations of maternal kin of European ancestry and a paternal parent-offspring relationship between an adult and child of African ancestry. These findings expand our understanding of the origins and familial relationships in late 17th and early 18th century North America.


Assuntos
População Negra , Migração Humana , Adulto , Criança , Humanos , População Negra/genética , Delaware , DNA Mitocondrial/genética , Genética Populacional , Haplótipos , Brancos
14.
Am J Biol Anthropol ; 181(4): 527-534, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37052272

RESUMO

In the United States, the Native American Graves Protection and Repatriation Act (NAGPRA) provides a specific framework for the disposition of Native American Ancestral remains within its purview. However, samples such as a bone fragment, tooth, or other biological tissue taken from the remains of these Ancestors have been treated by institutions and researchers as independent of the individual from whom they were removed and used in destructive research such as paleogenomic and other archaeometric analyses without consultation, consent, and collaboration from Native American communities; are not cared for in keeping with the current best practices for Indigenous Ancestors; and are not likely to be repatriated to their communities. Here, we demonstrate that any biological samples removed from Ancestors who are covered under NAGPRA must also be handled according to the stipulations defined for "human remains" within the legislation. As such, we are not proposing a change to existing legislation, but rather best practices, specific to the context of the United States and NAGPRA, relating to the use of and care for biological samples taken from Native American Ancestors.


Assuntos
Indígena Americano ou Nativo do Alasca , Cultura , Corpo Humano , Direitos Humanos , Indígenas Norte-Americanos , Humanos , Estados Unidos , Rituais Fúnebres , Direitos Humanos/legislação & jurisprudência
15.
Elife ; 122023 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-37070964

RESUMO

Archaeological cobs from Paredones and Huaca Prieta (Peru) represent some of the oldest maize known to date, yet they present relevant phenotypic traits corresponding to domesticated maize. This contrasts with the earliest Mexican macro-specimens from Guila Naquitz and San Marcos, which are phenotypically intermediate for these traits, even though they date more recently in time. To gain insights into the origins of ancient Peruvian maize, we sequenced DNA from three Paredones specimens dating ~6700-5000 calibrated years before present (BP), conducting comparative analyses with two teosinte subspecies (Zea mays ssp. mexicana and parviglumis) and extant maize, that include highland and lowland landraces from Mesoamerica and South America. We show that Paredones maize originated from the same domestication event as Mexican maize and was domesticated by ~6700 BP, implying rapid dispersal followed by improvement. Paredones maize shows no relevant gene flow from mexicana, smaller than that observed in teosinte parviglumis. Thus, Paredones samples represent the only maize without confounding mexicana variation found to date. It also harbors significantly fewer alleles previously found to be adaptive to highlands, but not of alleles adaptive to lowlands, supporting a lowland migration route. Our overall results imply that Paredones maize originated in Mesoamerica, arrived in Peru without mexicana introgression through a rapid lowland migration route, and underwent improvements in both Mesoamerica and South America.


The plant we know today as maize or corn began its story 9,000 years ago in modern-day Mexico, when farmers of the Balsas River basin started to carefully breed its ancestor, the wild grass teosinte parviglumis. Recent discoveries suggest the crop may have started to travel to South America before its domestication was fully complete, leading to a complex history of semi-tamed lineages evolving in parallel in different regions. For example, 5,300-year-old corn specimens found in Tehuacán, in central Mexico, still genetically and morphologically resemble teosinte. Meanwhile, cobs harvested about 6,700 to 5,000 years ago on the northern coast of Peru ­ 3800km away from where maize was first domesticated ­ look like the ones we know today. Vallebueno-Estrada et al. aimed to explore the evolutionary history of this Peruvian maize, which was discovered at the archaeological coastal site of Paredones. To do so, they extracted and sequenced its genetic information, and compared these sequences with those from modern varieties of lowland and highland maize, as well as from teosinte parviglumis and teosinte mexicana. The analyses showed that the ancestor of the Paredones maize emerged from teosinte parviglumis like any other lineage, but that it was already domesticated when it started to spread South; by the time it was present in Peru 6,700 years ago, it was genetically closer to modern-day crops. This early departure is consistent with the fact that the Paredones specimens lacked teosinte mexicana genetic variants; this highland relative of lowland parviglumis is believed to have interbred with maize lineages from Central America more recently, when these were brought to higher altitudes. The presence of genetic marks tailored to low-elevation regions suggested that the Paredones maize lineage migrated through a coastal corridor connecting Central and South America, arriving in northern Peru about 2,500 years after first arising from teosinte parviglumis in Central America around 9,000 years ago. Under the care of rapidly developing Central Andean societies, the crop then evolved to adapt to its local conditions. Maize today has spread to all continents besides Antarctica; we produce more of it than wheat, rice or any other grain. How our modern varieties will adapt to the environmental constraints brought by climate change remains unclear. By peering into the history of maize, Vallebueno-Estrada et al. hope to find genetic variations which could inform new breeding strategies that improve the future of this crop.


Assuntos
Domesticação , Zea mays , Peru , Zea mays/genética , América do Sul , México
16.
Genome Biol Evol ; 15(3)2023 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-36930529

RESUMO

Studies of ancient DNA have transformed our understanding of human evolution. Paleogenomics can also reveal historic and prehistoric agents of disease, including endemic, epidemic, and pandemic pathogens. Viruses-and in particular those with single- or double-stranded DNA genomes-are an important part of the paleogenomic revolution, preserving within some remains or environmental samples for tens of thousands of years. The results of these studies capture the public imagination, as well as giving scientists a unique perspective on some of the more slowly evolving viruses which cause disease. In this review, we revisit the first studies of historical virus genetic material in the 1990s, through to the genomic revolution of recent years. We look at how paleogenomics works for viral pathogens, such as the need for careful precautions against modern contamination and robust computational pipelines to identify and analyze authenticated viral sequences. We discuss the insights into virus evolution which have been gained through paleogenomics, concentrating on three DNA viruses in particular: parvovirus B19, herpes simplex virus 1, and smallpox. As we consider recent worldwide transmission of monkeypox and synthetic biology tools that allow the potential reconstruction of extinct viruses, we show that studying historical and ancient virus evolution has never been more topical.


Assuntos
Genômica , Vírus , Humanos , Genômica/métodos , DNA Antigo , Paleontologia , DNA , Vírus/genética
17.
Plant J ; 114(6): 1243-1266, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36919199

RESUMO

Grasses derive from a family of monocotyledonous plants that includes crops of major economic importance such as wheat, rice, sorghum and barley, sharing a common ancestor some 100 million years ago. The genomic attributes of plant adaptation remain obscure and the consequences of recurrent whole genome duplications (WGD) or polyploidization events, a major force in plant evolution, remain largely speculative. We conducted a comparative analysis of omics data from ten grass species to unveil structural (inversions, fusions, fissions, duplications, substitutions) and regulatory (expression and methylation) basis of genome plasticity, as possible attributes of plant long lasting evolution and adaptation. The present study demonstrates that diverged polyploid lineages sharing a common WGD event often present the same patterns of structural changes and evolutionary dynamics, but these patterns are difficult to generalize across independent WGD events as a result of non-WGD factors such as selection and domestication of crops. Polyploidy is unequivocally linked to the evolutionary success of grasses during the past 100 million years, although it remains difficult to attribute this success to particular genomic consequences of polyploidization, suggesting that polyploids harness the potential of genome duplication, at least partially, in lineage-specific ways. Overall, the present study clearly demonstrates that post-polyploidization reprogramming is more complex than traditionally reported in investigating single species and calls for a critical and comprehensive comparison across independently polyploidized lineages.


Assuntos
Genoma de Planta , Poaceae , Poaceae/genética , Genoma de Planta/genética , Filogenia , Evolução Molecular , Grão Comestível/genética , Poliploidia , Duplicação Gênica
18.
Curr Biol ; 33(7): 1365-1371.e3, 2023 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-36963383

RESUMO

Ancient DNA has revealed multiple episodes of admixture in human prehistory during geographic expansions associated with cultural innovations. One important example is the expansion of Neolithic agricultural groups out of the Near East into Europe and their consequent admixture with Mesolithic hunter-gatherers.1,2,3,4 Ancient genomes from this period provide an opportunity to study the role of admixture in providing new genetic variation for selection to act upon, and also to identify genomic regions that resisted hunter-gatherer introgression and may thus have contributed to agricultural adaptations. We used genome-wide DNA from 677 individuals spanning Mesolithic and Neolithic Europe to infer ancestry deviations in the genomes of admixed individuals and to test for natural selection after admixture by testing for deviations from a genome-wide null distribution. We find that the region around the pigmentation-associated gene SLC24A5 shows the greatest overrepresentation of Neolithic local ancestry in the genome (|Z| = 3.46). In contrast, we find the greatest overrepresentation of Mesolithic ancestry across the major histocompatibility complex (MHC; |Z| = 4.21), a major immunity locus, which also shows allele frequency deviations indicative of selection following admixture (p = 1 × 10-56). This could reflect negative frequency-dependent selection on MHC alleles common in Neolithic populations or that Mesolithic alleles were positively selected for and facilitated adaptation in Neolithic populations to pathogens or other environmental factors. Our study extends previous results that highlight immune function and pigmentation as targets of adaptation in more recent populations to selection processes in the Stone Age.


Assuntos
DNA , Fazendeiros , Humanos , Europa (Continente) , Alelos , Seleção Genética
19.
Struct Chem ; 34(2): 733-736, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36776693

RESUMO

The Nobel Assembly at Karolinska Institutet awarded the 2022 Nobel Prize in Physiology or Medicine to a Swedish geneticist, Svante Pääbo, for his discoveries concerning the genomes of extinct hominins and human evolution, for the sequencing of the genome of the Neanderthal, the discovery of a previously unknown hominin, Denisova, and the establishment of a new scientific discipline, paleogenomics.

20.
C R Biol ; 345(4): 111-128, 2023 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-36847121

RESUMO

The concept of translational research, which originated in the medical field in the 1980s, consists in improving the efficient transfer of research results obtained in a species (which can be considered as a model or pivot) to all the species for which these results are of interest for its improvement in Agriculture. In this context, comparative genomics is an important tool for translational research, effectively identifying genes controlling common functions between species. Editing and phenotyping tools must thus allow the functional validation of the gene conserved within the species for which the knowledge has been extrapolated, that is to say transferred, and the identification of the best alleles and associated genotypes for exploitation in current breeding programs.


Le concept de recherche translationnelle, issu du domaine médical dans les années 80, consiste à améliorer le transfert efficace des résultats de recherche obtenus chez une espèce (pouvant être considéré comme modèle ou pivot) à l'ensemble des espèces pour lesquelles ces résultats sont d'intérêt pour son amélioration en agriculture. Dans ce contexte, la génomique comparée constitue un outil important de la recherche translationnelle en identifiant efficacement les gènes contrôlant des fonctions communes entre espèces. Les outils d'édition génomique, de criblage de diversité génétique et de phénotypage doivent ainsi permettre la validation fonctionnelle du gène conservé au sein de l'espèce chez laquelle la connaissance a été extrapolée à partir de l'espèce pivot, c'est-à-dire transférée, ainsi que l'identification des meilleurs allèles et génotypes associés pour leur exploitation dans les programmes actuels de sélection.


Assuntos
Melhoramento Vegetal , Pesquisa Translacional Biomédica , Melhoramento Vegetal/métodos , Genômica/métodos , Produtos Agrícolas/genética , Genótipo , Genoma de Planta/genética
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