Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 367
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Cell ; 186(5): 923-939.e14, 2023 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-36868214

RESUMEN

We conduct high coverage (>30×) whole-genome sequencing of 180 individuals from 12 indigenous African populations. We identify millions of unreported variants, many predicted to be functionally important. We observe that the ancestors of southern African San and central African rainforest hunter-gatherers (RHG) diverged from other populations >200 kya and maintained a large effective population size. We observe evidence for ancient population structure in Africa and for multiple introgression events from "ghost" populations with highly diverged genetic lineages. Although currently geographically isolated, we observe evidence for gene flow between eastern and southern Khoesan-speaking hunter-gatherer populations lasting until ∼12 kya. We identify signatures of local adaptation for traits related to skin color, immune response, height, and metabolic processes. We identify a positively selected variant in the lightly pigmented San that influences pigmentation in vitro by regulating the enhancer activity and gene expression of PDPK1.


Asunto(s)
Aclimatación , Pigmentación de la Piel , Humanos , Secuenciación Completa del Genoma , Densidad de Población , África , Proteínas Quinasas Dependientes de 3-Fosfoinosítido
2.
Cell ; 179(3): 736-749.e15, 2019 10 17.
Artículo en Inglés | MEDLINE | ID: mdl-31626772

RESUMEN

Underrepresentation of Asian genomes has hindered population and medical genetics research on Asians, leading to population disparities in precision medicine. By whole-genome sequencing of 4,810 Singapore Chinese, Malays, and Indians, we found 98.3 million SNPs and small insertions or deletions, over half of which are novel. Population structure analysis demonstrated great representation of Asian genetic diversity by three ethnicities in Singapore and revealed a Malay-related novel ancestry component. Furthermore, demographic inference suggested that Malays split from Chinese ∼24,800 years ago and experienced significant admixture with East Asians ∼1,700 years ago, coinciding with the Austronesian expansion. Additionally, we identified 20 candidate loci for natural selection, 14 of which harbored robust associations with complex traits and diseases. Finally, we show that our data can substantially improve genotype imputation in diverse Asian and Oceanian populations. These results highlight the value of our data as a resource to empower human genetics discovery across broad geographic regions.


Asunto(s)
Genética de Población , Genoma Humano/genética , Selección Genética , Secuenciación Completa del Genoma , Pueblo Asiatico/genética , Femenino , Genotipo , Humanos , Malasia/epidemiología , Masculino , Polimorfismo de Nucleótido Simple/genética , Singapur/epidemiología
3.
Proc Natl Acad Sci U S A ; 120(7): e2201076120, 2023 02 14.
Artículo en Inglés | MEDLINE | ID: mdl-36749728

RESUMEN

Sea turtles represent an ancient lineage of marine vertebrates that evolved from terrestrial ancestors over 100 Mya. The genomic basis of the unique physiological and ecological traits enabling these species to thrive in diverse marine habitats remains largely unknown. Additionally, many populations have drastically declined due to anthropogenic activities over the past two centuries, and their recovery is a high global conservation priority. We generated and analyzed high-quality reference genomes for the leatherback (Dermochelys coriacea) and green (Chelonia mydas) turtles, representing the two extant sea turtle families. These genomes are highly syntenic and homologous, but localized regions of noncollinearity were associated with higher copy numbers of immune, zinc-finger, and olfactory receptor (OR) genes in green turtles, with ORs related to waterborne odorants greatly expanded in green turtles. Our findings suggest that divergent evolution of these key gene families may underlie immunological and sensory adaptations assisting navigation, occupancy of neritic versus pelagic environments, and diet specialization. Reduced collinearity was especially prevalent in microchromosomes, with greater gene content, heterozygosity, and genetic distances between species, supporting their critical role in vertebrate evolutionary adaptation. Finally, diversity and demographic histories starkly contrasted between species, indicating that leatherback turtles have had a low yet stable effective population size, exhibit extremely low diversity compared with other reptiles, and harbor a higher genetic load compared with green turtles, reinforcing concern over their persistence under future climate scenarios. These genomes provide invaluable resources for advancing our understanding of evolution and conservation best practices in an imperiled vertebrate lineage.


Asunto(s)
Tortugas , Animales , Ecosistema , Dinámica Poblacional
4.
Plant J ; 117(1): 177-192, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37797086

RESUMEN

'Living fossils', that is, ancient lineages of low taxonomic diversity, represent an exceptional evolutionary heritage, yet we know little about how demographic history and deleterious mutation load have affected their long-term survival and extinction risk. We performed whole-genome sequencing and population genomic analyses on Dipteronia sinensis and D. dyeriana, two East Asian Tertiary relict trees. We found large-scale genome reorganizations and identified species-specific genes under positive selection that are likely involved in adaptation. Our demographic analyses suggest that the wider-ranged D. sinensis repeatedly recovered from population bottlenecks over late Tertiary/Quaternary periods of adverse climate conditions, while the population size of the narrow-ranged D. dyeriana steadily decreased since the late Miocene, especially after the Last Glacial Maximum (LGM). We conclude that the efficient purging of deleterious mutations in D. sinensis facilitated its survival and repeated demographic recovery. By contrast, in D. dyeriana, increased genetic drift and reduced selection efficacy, due to recent severe population bottlenecks and a likely preponderance of vegetative propagation, resulted in fixation of strongly deleterious mutations, reduced fitness, and continuous population decline, with likely detrimental consequences for the species' future viability and adaptive potential. Overall, our findings highlight the significant impact of demographic history on levels of accumulation and purging of putatively deleterious mutations that likely determine the long-term survival and extinction risk of Tertiary relict trees.


Asunto(s)
Fósiles , Endogamia , Árboles , Animales , Variación Genética , Metagenómica , Mutación , Árboles/genética
5.
Mol Biol Evol ; 41(5)2024 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-38636507

RESUMEN

Inferring past demographic history of natural populations from genomic data is of central concern in many studies across research fields. Previously, our group had developed dadi, a widely used demographic history inference method based on the allele frequency spectrum (AFS) and maximum composite-likelihood optimization. However, dadi's optimization procedure can be computationally expensive. Here, we present donni (demography optimization via neural network inference), a new inference method based on dadi that is more efficient while maintaining comparable inference accuracy. For each dadi-supported demographic model, donni simulates the expected AFS for a range of model parameters then trains a set of Mean Variance Estimation neural networks using the simulated AFS. Trained networks can then be used to instantaneously infer the model parameters from future genomic data summarized by an AFS. We demonstrate that for many demographic models, donni can infer some parameters, such as population size changes, very well and other parameters, such as migration rates and times of demographic events, fairly well. Importantly, donni provides both parameter and confidence interval estimates from input AFS with accuracy comparable to parameters inferred by dadi's likelihood optimization while bypassing its long and computationally intensive evaluation process. donni's performance demonstrates that supervised machine learning algorithms may be a promising avenue for developing more sustainable and computationally efficient demographic history inference methods.


Asunto(s)
Frecuencia de los Genes , Modelos Genéticos , Aprendizaje Automático Supervisado , Genética de Población/métodos , Redes Neurales de la Computación , Humanos
6.
Proc Natl Acad Sci U S A ; 119(40): e2123030119, 2022 10 04.
Artículo en Inglés | MEDLINE | ID: mdl-36161902

RESUMEN

Lorises are a group of globally threatened strepsirrhine primates that exhibit many unusual physiological and behavioral features, including a low metabolic rate, slow movement, and hibernation. Here, we assembled a chromosome-level genome sequence of the pygmy loris (Xanthonycticebus pygmaeus) and resequenced whole genomes from 50 pygmy lorises and 6 Bengal slow lorises (Nycticebus bengalensis). We found that many gene families involved in detoxification have been specifically expanded in the pygmy loris, including the GSTA gene family, with many newly derived copies functioning specifically in the liver. We detected many genes displaying evolutionary convergence between pygmy loris and koala, including PITRM1. Significant decreases in PITRM1 enzymatic activity in these two species may have contributed to their characteristic low rate of metabolism. We also detected many evolutionarily convergent genes and positively selected genes in the pygmy loris that are involved in muscle development. Functional assays demonstrated the decreased ability of one positively selected gene, MYOF, to up-regulate the fast-type muscle fiber, consistent with the lower proportion of fast-twitch muscle fibers in the pygmy loris. The protein product of another positively selected gene in the pygmy loris, PER2, exhibited weaker binding to the key circadian core protein CRY, a finding that may be related to this species' unusual circadian rhythm. Finally, population genomics analysis revealed that these two extant loris species, which coexist in the same habitat, have exhibited an inverse relationship in terms of their demography over the past 1 million years, implying strong interspecies competition after speciation.


Asunto(s)
Adaptación Biológica , Evolución Biológica , Lorisidae , Adaptación Biológica/genética , Animales , Demografía , Hibernación , Lorisidae/genética , Metagenómica , Metaloendopeptidasas/genética
7.
Proc Natl Acad Sci U S A ; 119(25): e2119281119, 2022 06 21.
Artículo en Inglés | MEDLINE | ID: mdl-35696575

RESUMEN

Haplotype-based analyses have recently been leveraged to interrogate the fine-scale structure in specific geographic regions, notably in Europe, although an equivalent haplotype-based understanding across the whole of Europe with these tools is lacking. Furthermore, study of identity-by-descent (IBD) sharing in a large sample of haplotypes across Europe would allow a direct comparison between different demographic histories of different regions. The UK Biobank (UKBB) is a population-scale dataset of genotype and phenotype data collected from the United Kingdom, with established sampling of worldwide ancestries. The exact content of these non-UK ancestries is largely uncharacterized, where study could highlight valuable intracontinental ancestry references with deep phenotyping within the UKBB. In this context, we sought to investigate the sample of European ancestry captured in the UKBB. We studied the haplotypes of 5,500 UKBB individuals with a European birthplace; investigated the population structure and demographic history in Europe, showing in parallel the variety of footprints of demographic history in different genetic regions around Europe; and expand knowledge of the genetic landscape of the east and southeast of Europe. Providing an updated map of European genetics, we leverage IBD-segment sharing to explore the extent of population isolation and size across the continent. In addition to building and expanding upon previous knowledge in Europe, our results show the UKBB as a source of diverse ancestries beyond Britain. These worldwide ancestries sampled in the UKBB may complement and inform researchers interested in specific communities or regions not limited to Britain.


Asunto(s)
Haplotipos , Población , Bases de Datos Genéticas , Conjuntos de Datos como Asunto , Demografía , Europa (Continente) , Variación Genética , Población/genética
8.
BMC Biol ; 22(1): 18, 2024 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-38273256

RESUMEN

BACKGROUND: The underrepresentation of Hmong-Mien (HM) people in Asian genomic studies has hindered our comprehensive understanding of the full landscape of their evolutionary history and complex trait architecture. South China is a multi-ethnic region and indigenously settled by ethnolinguistically diverse HM, Austroasiatic (AA), Tai-Kadai (TK), Austronesian (AN), and Sino-Tibetan (ST) people, which is regarded as East Asia's initial cradle of biodiversity. However, previous fragmented genetic studies have only presented a fraction of the landscape of genetic diversity in this region, especially the lack of haplotype-based genomic resources. The deep characterization of demographic history and natural-selection-relevant genetic architecture of HM people was necessary. RESULTS: We reported one HM-specific genomic resource and comprehensively explored the fine-scale genetic structure and adaptative features inferred from the genome-wide SNP data of 440 HM individuals from 33 ethnolinguistic populations, including previously unreported She. We identified solid genetic differentiation between HM people and Han Chinese at 7.64‒15.86 years ago (kya) and split events between southern Chinese inland (Miao/Yao) and coastal (She) HM people in the middle Bronze Age period and the latter obtained more gene flow from Ancient Northern East Asians. Multiple admixture models further confirmed that extensive gene flow from surrounding ST, TK, and AN people entangled in forming the gene pool of Chinese coastal HM people. Genetic findings of isolated shared unique ancestral components based on the sharing alleles and haplotypes deconstructed that HM people from the Yungui Plateau carried the breadth of previously unknown genomic diversity. We identified a direct and recent genetic connection between Chinese inland and Southeast Asian HM people as they shared the most extended identity-by-descent fragments, supporting the long-distance migration hypothesis. Uniparental phylogenetic topology and network-based phylogenetic relationship reconstruction found ancient uniparental founding lineages in southwestern HM people. Finally, the population-specific biological adaptation study identified the shared and differentiated natural selection signatures among inland and coastal HM people associated with physical features and immune functions. The allele frequency spectrum of cancer susceptibility alleles and pharmacogenomic genes showed significant differences between HM and northern Chinese people. CONCLUSIONS: Our extensive genetic evidence combined with the historical documents supported the view that ancient HM people originated from the Yungui regions associated with ancient "Three-Miao tribes" descended from the ancient Daxi-Qujialing-Shijiahe people. Then, some have recently migrated rapidly to Southeast Asia, and some have migrated eastward and mixed respectively with Southeast Asian indigenes, Liangzhu-related coastal ancient populations, and incoming southward ST people. Generally, complex population migration, admixture, and adaptation history contributed to the complicated patterns of population structure of geographically diverse HM people.


Asunto(s)
Pueblos del Este de Asia , Genética de Población , Humanos , China , Genómica , Haplotipos , Filogenia
9.
BMC Genomics ; 25(1): 373, 2024 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-38627659

RESUMEN

The common dolphin (Delphinus delphis) is widely distributed worldwide and well adapted to various habitats. Animal genomes store clues about their pasts, and can reveal the genes underlying their evolutionary success. Here, we report the first high-quality chromosome-level genome of D. delphis. The assembled genome size was 2.56 Gb with a contig N50 of 63.85 Mb. Phylogenetically, D. delphis was close to Tursiops truncatus and T. aduncus. The genome of D. delphis exhibited 428 expanded and 1,885 contracted gene families, and 120 genes were identified as positively selected. The expansion of the HSP70 gene family suggested that D. delphis has a powerful system for buffering stress, which might be associated with its broad adaptability, longevity, and detoxification capacity. The expanded IFN-α and IFN-ω gene families, as well as the positively selected genes encoding tripartite motif-containing protein 25, peptidyl-prolyl cis-trans isomerase NIMA-interacting 1, and p38 MAP kinase, were all involved in pathways for antiviral, anti-inflammatory, and antineoplastic mechanisms. The genome data also revealed dramatic fluctuations in the effective population size during the Pleistocene. Overall, the high-quality genome assembly and annotation represent significant molecular resources for ecological and evolutionary studies of Delphinus and help support their sustainable treatment and conservation.


Asunto(s)
Delfín Común , Animales , Evolución Biológica , Cromosomas/genética , Inmunidad Innata/genética , Filogenia
10.
Mol Biol Evol ; 40(11)2023 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-37713621

RESUMEN

Conservation genetic analyses of many endangered species have been based on genotyping of microsatellite loci and sequencing of short fragments of mtDNA. The increase in power and resolution afforded by whole genome approaches may challenge conclusions made on limited numbers of loci and maternally inherited haploid markers. Here, we provide a matched comparison of whole genome sequencing versus microsatellite and control region (CR) genotyping for Eurasian otters (Lutra lutra). Previous work identified four genetically differentiated "stronghold" populations of otter in Britain, derived from regional populations that survived the population crash of the 1950s-1980s. Using whole genome resequencing data from 45 samples from across the British stronghold populations, we confirmed some aspects of population structure derived from previous marker-driven studies. Importantly, we showed that genomic signals of the population crash bottlenecks matched evidence from otter population surveys. Unexpectedly, two strongly divergent mitochondrial lineages were identified that were undetectable using CR fragments, and otters in the east of England were genetically distinct and surprisingly variable. We hypothesize that this previously unsuspected variability may derive from past releases of Eurasian otters from other, non-British source populations in England around the time of the population bottleneck. Our work highlights that even reasonably well-studied species may harbor genetic surprises, if studied using modern high-throughput sequencing methods.


Asunto(s)
Nutrias , Animales , Nutrias/genética , Reino Unido , ADN Mitocondrial/genética , Especies en Peligro de Extinción , Genómica
11.
Mol Biol Evol ; 40(3)2023 03 04.
Artículo en Inglés | MEDLINE | ID: mdl-36661852

RESUMEN

Novel technologies for recovering DNA information from archaeological and historical specimens have made available an ever-increasing amount of temporally spaced genetic samples from natural populations. These genetic time series permit the direct assessment of patterns of temporal changes in allele frequencies and hold the promise of improving power for the inference of selection. Increased time resolution can further facilitate testing hypotheses regarding the drivers of past selection events such as the incidence of plant and animal domestication. However, studying past selection processes through ancient DNA (aDNA) still involves considerable obstacles such as postmortem damage, high fragmentation, low coverage, and small samples. To circumvent these challenges, we introduce a novel Bayesian framework for the inference of temporally variable selection based on genotype likelihoods instead of allele frequencies, thereby enabling us to model sample uncertainties resulting from the damage and fragmentation of aDNA molecules. Also, our approach permits the reconstruction of the underlying allele frequency trajectories of the population through time, which allows for a better understanding of the drivers of selection. We evaluate its performance through extensive simulations and demonstrate its utility with an application to the ancient horse samples genotyped at the loci for coat coloration. Our results reveal that incorporating sample uncertainties can further improve the inference of selection.


Asunto(s)
ADN Antiguo , ADN , Animales , Caballos/genética , Teorema de Bayes , Frecuencia de los Genes , ADN/genética , Factores de Tiempo , Modelos Genéticos
12.
Mol Biol Evol ; 40(12)2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37987559

RESUMEN

Even in the genomics era, the phylogeny of Neotropical small felids comprised in the genus Leopardus remains contentious. We used whole-genome resequencing data to construct a time-calibrated consensus phylogeny of this group, quantify phylogenomic discordance, test for interspecies introgression, and assess patterns of genetic diversity and demographic history. We infer that the Leopardus radiation started in the Early Pliocene as an initial speciation burst, followed by another in its subgenus Oncifelis during the Early Pleistocene. Our findings challenge the long-held notion that ocelot (Leopardus pardalis) and margay (L. wiedii) are sister species and instead indicate that margay is most closely related to the enigmatic Andean cat (L. jacobita), whose whole-genome data are reported here for the first time. In addition, we found that the newly sampled Andean tiger cat (L. tigrinus pardinoides) population from Colombia associates closely with Central American tiger cats (L. tigrinus oncilla). Genealogical discordance was largely attributable to incomplete lineage sorting, yet was augmented by strong gene flow between ocelot and the ancestral branch of Oncifelis, as well as between Geoffroy's cat (L. geoffroyi) and southern tiger cat (L. guttulus). Contrasting demographic trajectories have led to disparate levels of current genomic diversity, with a nearly tenfold difference in heterozygosity between Andean cat and ocelot, spanning the entire range of variability found in extant felids. Our analyses improved our understanding of the speciation history and diversity patterns in this felid radiation, and highlight the benefits to phylogenomic inference of embracing the many heterogeneous signals scattered across the genome.


Asunto(s)
Felidae , Tigres , Animales , Filogenia , Felidae/genética , Evolución Biológica , Flujo Génico
13.
BMC Plant Biol ; 24(1): 39, 2024 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-38195447

RESUMEN

BACKGROUND: Quercus aliena is a major montane tree species of subtropical and temperate forests in China, with important ecological and economic value. In order to reveal the species' population dynamics, genetic diversity, genetic structure, and association with mountain habitats during the evolutionary process, we re-sequenced the genomes of 72 Q. aliena individuals. RESULTS: The whole chloroplast and nuclear genomes were used for this study. Phylogenetic analysis using the chloroplast genome dataset supported four clades of Q. aliena, while the nuclear dataset supported three major clades. Sex-biased dispersal had a critical role in causing discordance between the chloroplast and nuclear genomes. Population structure analysis showed two groups in Q. aliena. The effective population size sharply declined 1 Mya, coinciding with the Poyang Glaciation in Eastern China. Using genotype-climate association analyses, we found a positive correlation between allele frequency variation in SNPs and temperature, suggesting the species has the capacity to adapt to changing temperatures. CONCLUSION: Overall, this study illustrates the genetic divergence, genomic variation, and evolutionary processes behind the demographic history of Q. aliena.


Asunto(s)
Quercus , Humanos , Quercus/genética , Filogenia , Genómica , Densidad de Población , Dinámica Poblacional
14.
Planta ; 259(2): 45, 2024 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-38281265

RESUMEN

MAIN CONCLUSION: The divergence of subsect. Gerardianae was likely triggered by the uplift of the Qinghai-Tibetan Plateau and adjacent mountains. Pinus bungeana might have probably experienced expansion since Last Interglacial period. Historical geological and climatic oscillations have profoundly affected patterns of nucleotide variability, evolutionary history, and species divergence in numerous plants of the Northern Hemisphere. However, how long-lived conifers responded to geological and climatic fluctuations in East Asia remain poorly understood. Here, based on paternally inherited chloroplast genomes and maternally inherited mitochondrial DNA markers, we investigated the population demographic history and molecular evolution of subsect. Gerardianae (only including three species, Pinus bungeana, P. gerardiana, and P. squamata) of Pinus. A low level of nucleotide diversity was found in P. bungeana (π was 0.00016 in chloroplast DNA sequences, and 0.00304 in mitochondrial DNAs). The haplotype-based phylogenetic topology and unimodal distributions of demographic analysis suggested that P. bungeana probably originated in the southern Qinling Mountains and experienced rapid population expansion since Last Interglacial period. Phylogenetic analysis revealed that P. gerardiana and P. squamata had closer genetic relationship. The species divergence of subsect. Gerardianae occurred about 27.18 million years ago (Mya) during the middle to late Oligocene, which was significantly associated with the uplift of the Qinghai-Tibetan Plateau and adjacent mountains from the Eocene to the mid-Pliocene. The molecular evolutionary analysis showed that two chloroplast genes (psaI and ycf1) were under positive selection, the genetic lineages of P. bungeana exhibited higher transition and nonsynonymous mutations, which were involved with the strongly environmental adaptation. These findings shed light on the population evolutionary history of white pine species and provide striking insights for comprehension of their species divergence and molecular evolution.


Asunto(s)
Genoma del Cloroplasto , Pinus , Filogenia , Pinus/genética , Genoma del Cloroplasto/genética , Evolución Molecular , ADN de Cloroplastos/genética , ADN Mitocondrial/genética , Nucleótidos , Demografía , Variación Genética
15.
New Phytol ; 242(5): 2353-2368, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38515228

RESUMEN

Evolutionary radiation, a pivotal aspect of macroevolution, offers valuable insights into evolutionary processes. The genus Pinus is the largest genus in conifers with c . 90% of the extant species emerged in the Miocene, which signifies a case of rapid diversification. Despite this remarkable history, our understanding of the mechanisms driving radiation within this expansive genus has remained limited. Using exome capture sequencing and a fossil-calibrated phylogeny, we investigated the divergence history, niche diversification, and introgression among 13 closely related Eurasian species spanning climate zones from the tropics to the boreal Arctic. We detected complex introgression among lineages in subsection Pinus at all stages of the phylogeny. Despite this widespread gene exchange, each species maintained its genetic identity and showed clear niche differentiation. Demographic analysis unveiled distinct population histories among these species, which further influenced the nucleotide diversity and efficacy of purifying and positive selection in each species. Our findings suggest that radiation in the Eurasian pines was likely fueled by interspecific recombination and further reinforced by their adaptation to distinct environments. Our study highlights the constraints and opportunities for evolutionary change, and the expectations of future adaptation in response to environmental changes in different lineages.


Asunto(s)
Flujo Génico , Filogenia , Pinus , Pinus/genética , Pinus/efectos de la radiación , Evolución Biológica , Variación Genética , Especificidad de la Especie , Europa (Continente) , Especiación Genética
16.
New Phytol ; 242(2): 774-785, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38389217

RESUMEN

C4 photosynthesis is a key innovation in land plant evolution, but its immediate effects on population demography are unclear. We explore the early impact of the C4 trait on the trajectories of C4 and non-C4 populations of the grass Alloteropsis semialata. We combine niche models projected into paleoclimate layers for the last 5 million years with demographic models based on genomic data. The initial split between C4 and non-C4 populations was followed by a larger expansion of the ancestral C4 population, and further diversification led to the unparalleled expansion of descendant C4 populations. Overall, C4 populations spread over three continents and achieved the highest population growth, in agreement with a broader climatic niche that rendered a large potential range over time. The C4 populations that remained in the region of origin, however, experienced lower population growth, rather consistent with local geographic constraints. Moreover, the posterior transfer of some C4-related characters to non-C4 counterparts might have facilitated the recent expansion of non-C4 populations in the region of origin. Altogether, our findings support that C4 photosynthesis provided an immediate demographic advantage to A. semialata populations, but its effect might be masked by geographic contingencies.


Asunto(s)
Fotosíntesis , Poaceae , Poaceae/genética , Fenotipo , Demografía
17.
Mol Ecol ; : e17475, 2024 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-39021282

RESUMEN

The last glacial period is known to have greatly influenced the demographic history of temperate forest trees, with important range contractions and post-glacial expansions that led to the formation of multiple genetic lineages and secondary contact zones in the Northern Hemisphere. These dynamics have been extensively studied for European and North American species but are still poorly understood in other temperate regions of rich biodiversity such as the Caucasus. Our study helps filling that gap by deciphering the genomic landscapes of F. orientalis across the South Caucasus. The use of genome-wide data confirmed a past demographic history strongly influenced by the Last Glacial Maximum, revealing two disjunct glacial refugia in the Colchis and Hyrcanian regions. The resulting patterns of genetic diversity, load and differentiation are not always concordant across the region, with genetic load pinpointing the location of the glacial refugia more efficiently than genetic diversity alone. The Hyrcanian forests show depleted genetic diversity and substantial isolation, even if long-distance gene flow is still present with the main centre of diversity in the Greater Caucasus. Finally, we characterize a strong heterogeneity of genetic diversity and differentiation along the species chromosomes, with noticeably a first chromosome showing low diversity and weak differentiation.

18.
Mol Ecol ; : e17367, 2024 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-38686435

RESUMEN

Population genomics analysis holds great potential for informing conservation of endangered populations. We focused on a controversial case of European whitefish (Coregonus spp.) populations. The endangered North Sea houting is the only coregonid fish that tolerates oceanic salinities and was previously considered a species (C. oxyrhinchus) distinct from European lake whitefish (C. lavaretus). However, no firm evidence for genetic-based salinity adaptation has been available. Also, studies based on microsatellite and mitogenome data suggested surprisingly recent divergence (c. 2500 years bp) between houting and lake whitefish. These data types furthermore have provided no evidence for possible inbreeding. Finally, a controversial taxonomic revision recently classified all whitefish in the region as C. maraena, calling conservation priorities of houting into question. We used whole-genome and ddRAD sequencing to analyse six lake whitefish populations and the only extant indigenous houting population. Demographic inference indicated post-glacial expansion and divergence between lake whitefish and houting occurring not long after the Last Glaciation, implying deeper population histories than previous analyses. Runs of homozygosity analysis suggested not only high inbreeding (FROH up to 30.6%) in some freshwater populations but also FROH up to 10.6% in the houting prompting conservation concerns. Finally, outlier scans provided evidence for adaptation to high salinities in the houting. Applying a framework for defining conservation units based on current and historical reproductive isolation and adaptive divergence led us to recommend that the houting be treated as a separate conservation unit regardless of species status. In total, the results underscore the potential of genomics to inform conservation practices, in this case clarifying conservation units and highlighting populations of concern.

19.
Mol Phylogenet Evol ; 195: 108055, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38485106

RESUMEN

Comparative phylogeographic studies of closely related species sharing co-distribution areas can elucidate the role of shared historical factors and environmental changes in shaping their phylogeographic pattern. The bean bugs, Riptortus pedestris and Riptortus linearis, which both inhabit subtropical regions in East Asia, are recognized as highly destructive soybean pests. Many previous studies have investigated the biological characteristics, pheromones, chemicals and control mechanisms of these two pests, but few studies have explored their phylogeographic patterns and underlying factors. In this study, we generated a double-digest restriction site-associated DNA sequencing (ddRAD-seq) dataset to investigate phylogeographic patterns and construct ecological niche models (ENM) for both Riptortus species. Our findings revealed similar niche occupancies and population genetic structures between the two species, with each comprising two phylogeographic lineages (i.e., the mainland China and the Indochina Peninsula clades) that diverged approximately 0.1 and 0.3 million years ago, respectively. This divergence likely resulted from the combined effects of temperatures variation and geographical barriers in the mountainous regions of Southwest China. Further demographic history and ENM analyses suggested that both pests underwent rapid expansion prior to the Last Glacial Maximum (LGM). Furthermore, ENM predicts a northward shift of both pests into new soybean-producing regions due to global warming. Our study indicated that co-distribution soybean pests with overlapping ecological niches and similar life histories in subtropical regions of East Asia exhibit congruent phylogeographic and demographic patterns in response to shared historical biogeographic drivers.


Asunto(s)
Glycine max , Heterópteros , Animales , Glycine max/genética , Filogenia , Variación Genética , Evolución Molecular , ADN Mitocondrial/genética , Filogeografía , Asia Oriental , Heterópteros/genética
20.
Mol Phylogenet Evol ; 194: 108042, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38401812

RESUMEN

Climate changes at larger scales have influenced dispersal and range shifts of many taxa in East Asia. The fascicularis species group of macaques is composed of four species and is widely distributed in Southeast and East Asia. However, its phylogeography and demographic histories are currently poorly understood. Herein, we assembled autosomal, mitogenome, and Y-chromosome data for 106 individuals, and combined them with 174 mtDNA dloop haplotypes of this species group, with particular focus on the demographic histories and dispersal routes of Macaca fuscata, M. cyclopis, and M. mulatta. The results showed: (1) three monophyletic clades for M. fuscata, M. cyclopis, and M. mulatta based on the multiple genomics analyses; (2) the disparate demographic trajectories of the three species after their split ∼1.0 Ma revealed that M. cyclopis and M. fuscata were derived from an ancestral M. mulatta population; (3) the speciation time of M. cyclopis was later than that of M. fuscata, and their divergence time occurred at the beginning of "Ryukyu Coral Sea Stage" (1.0-0.2 Ma) when the East China Sea land bridge was completely submerged by the sea level rose; and (4) the three parallel rivers (Nujiang, Lancangjiang, and Jinshajiang) of Southwestern China divided M. mulatta into Indian and Chinese genetic populations ∼200 kya. These results shed light on understanding not only the evolutionary history of the fascicularis species group but also the formation mechanism of faunal diversity in East Asia during the Pleistocene.


Asunto(s)
Macaca fuscata , Macaca , Animales , Filogeografía , Filogenia , Macaca fuscata/genética , Macaca/genética , Asia Oriental , ADN Mitocondrial/genética , Genómica , Demografía
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA