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1.
Cell ; 177(4): 1010-1021.e32, 2019 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-30981557

RESUMO

Genome sequences are known for two archaic hominins-Neanderthals and Denisovans-which interbred with anatomically modern humans as they dispersed out of Africa. We identified high-confidence archaic haplotypes in 161 new genomes spanning 14 island groups in Island Southeast Asia and New Guinea and found large stretches of DNA that are inconsistent with a single introgressing Denisovan origin. Instead, modern Papuans carry hundreds of gene variants from two deeply divergent Denisovan lineages that separated over 350 thousand years ago. Spatial and temporal structure among these lineages suggest that introgression from one of these Denisovan groups predominantly took place east of the Wallace line and continued until near the end of the Pleistocene. A third Denisovan lineage occurs in modern East Asians. This regional mosaic suggests considerable complexity in archaic contact, with modern humans interbreeding with multiple Denisovan groups that were geographically isolated from each other over deep evolutionary time.


Assuntos
Introgressão Genética/genética , Haplótipos/genética , Hominidae/genética , Animais , Povo Asiático/genética , Evolução Biológica , Fluxo Gênico , Variação Genética/genética , Genoma Humano/genética , Humanos , Indonésia , Homem de Neandertal/genética , Oceania
2.
Nat Immunol ; 20(10): 1299-1310, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31534238

RESUMO

Resisting and tolerating microbes are alternative strategies to survive infection, but little is known about the evolutionary mechanisms controlling this balance. Here genomic analyses of anatomically modern humans, extinct Denisovan hominins and mice revealed a TNFAIP3 allelic series with alterations in the encoded immune response inhibitor A20. Each TNFAIP3 allele encoded substitutions at non-catalytic residues of the ubiquitin protease OTU domain that diminished IκB kinase-dependent phosphorylation and activation of A20. Two TNFAIP3 alleles encoding A20 proteins with partial phosphorylation deficits seemed to be beneficial by increasing immunity without causing spontaneous inflammatory disease: A20 T108A;I207L, originating in Denisovans and introgressed in modern humans throughout Oceania, and A20 I325N, from an N-ethyl-N-nitrosourea (ENU)-mutagenized mouse strain. By contrast, a rare human TNFAIP3 allele encoding an A20 protein with 95% loss of phosphorylation, C243Y, caused spontaneous inflammatory disease in humans and mice. Analysis of the partial-phosphorylation A20 I325N allele in mice revealed diminished tolerance of bacterial lipopolysaccharide and poxvirus inoculation as tradeoffs for enhanced immunity.


Assuntos
Infecções por Poxviridae/imunologia , Poxviridae/fisiologia , Domínios Proteicos/genética , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/genética , Alelos , Animais , Extinção Biológica , Humanos , Imunidade , Inflamação , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mutação de Sentido Incorreto/genética , Fosforilação
3.
Am J Hum Genet ; 109(1): 50-65, 2022 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-34919805

RESUMO

Lack of diversity in human genomics limits our understanding of the genetic underpinnings of complex traits, hinders precision medicine, and contributes to health disparities. To map genetic effects on gene regulation in the underrepresented Indonesian population, we have integrated genotype, gene expression, and CpG methylation data from 115 participants across three island populations that capture the major sources of genomic diversity in the region. In a comparison with European datasets, we identify eQTLs shared between Indonesia and Europe as well as population-specific eQTLs that exhibit differences in allele frequencies and/or overall expression levels between populations. By combining local ancestry and archaic introgression inference with eQTLs and methylQTLs, we identify regulatory loci driven by modern Papuan ancestry as well as introgressed Denisovan and Neanderthal variation. GWAS colocalization connects QTLs detected here to hematological traits, and further comparison with European datasets reflects the poor overall transferability of GWAS statistics across diverse populations. Our findings illustrate how population-specific genetic architecture, local ancestry, and archaic introgression drive variation in gene regulation across genetically distinct and in admixed populations and highlight the need for performing association studies on non-European populations.


Assuntos
Regulação da Expressão Gênica , Genética Populacional , Genoma Humano , Locos de Características Quantitativas , Biologia Computacional/métodos , Metilação de DNA , Bases de Dados Genéticas , Estudo de Associação Genômica Ampla , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Indonésia , Masculino , Modelos Genéticos , Anotação de Sequência Molecular , Herança Multifatorial , Característica Quantitativa Herdável , Seleção Genética , Sequenciamento Completo do Genoma
4.
PLoS Genet ; 18(12): e1010470, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36480515

RESUMO

Modern humans have admixed with multiple archaic hominins. Papuans, in particular, owe up to 5% of their genome to Denisovans, a sister group to Neanderthals whose remains have only been identified in Siberia and Tibet. Unfortunately, the biological and evolutionary significance of these introgression events remain poorly understood. Here we investigate the function of both Denisovan and Neanderthal alleles characterised within a set of 56 genomes from Papuan individuals. By comparing the distribution of archaic and non-archaic variants we assess the consequences of archaic admixture across a multitude of different cell types and functional elements. We observe an enrichment of archaic alleles within cis-regulatory elements and transcribed regions of the genome, with Denisovan variants strongly affecting elements active within immune-related cells. We identify 16,048 and 10,032 high-confidence Denisovan and Neanderthal variants that fall within annotated cis-regulatory elements and with the potential to alter the affinity of multiple transcription factors to their cognate DNA motifs, highlighting a likely mechanism by which introgressed DNA can impact phenotypes. Lastly, we experimentally validate these predictions by testing the regulatory potential of five Denisovan variants segregating within Papuan individuals, and find that two are associated with a significant reduction of transcriptional activity in plasmid reporter assays. Together, these data provide support for a widespread contribution of archaic DNA in shaping the present levels of modern human genetic diversity, with different archaic ancestries potentially affecting multiple phenotypic traits within non-Africans.


Assuntos
Evolução Molecular , Hominidae , Sistema Imunitário , Homem de Neandertal , Humanos , Hominidae/genética , Homem de Neandertal/genética , Papua Nova Guiné
5.
Mol Biol Evol ; 39(3)2022 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-35294555

RESUMO

Island Southeast Asia (ISEA) and Oceania host one of the world's richest assemblages of human phenotypic, linguistic, and cultural diversity. Despite this, the region's male genetic lineages are globally among the last to remain unresolved. We compiled ∼9.7 Mb of Y chromosome (chrY) sequence from a diverse sample of over 380 men from this region, including 152 first reported here. The granularity of this data set allows us to fully resolve and date the regional chrY phylogeny. This new high-resolution tree confirms two main population bursts: multiple rapid diversifications following the region's initial settlement ∼50 kya, and extensive expansions <6 kya. Notably, ∼40-25 kya the deep rooting local lineages of C-M130, M-P256, and S-B254 show almost no further branching events in ISEA, New Guinea, and Australia, matching a similar pause in diversification seen in maternal mitochondrial DNA lineages. The main local lineages start diversifying ∼25 kya, at the time of the last glacial maximum. This improved chrY topology highlights localized events with important historical implications, including pre-Holocene contact between Mainland and ISEA, potential interactions between Australia and the Papuan world, and a sustained period of diversification following the flooding of the ancient Sunda and Sahul continents as the insular landscape observed today formed. The high-resolution phylogeny of the chrY presented here thus enables a detailed exploration of past isolation, interaction, and change in one of the world's least understood regions.


Assuntos
Povo Asiático , DNA Mitocondrial , Sudeste Asiático , DNA Mitocondrial/genética , Humanos , Masculino , Mitocôndrias/genética , Filogenia
6.
Fungal Genet Biol ; 169: 103827, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37640199

RESUMO

Vegetative incompatibility is a fungal allorecognition system characterised by the inability of genetically distinct conspecific fungal strains to form a viable heterokaryon and is controlled by multiple polymorphic loci termed vic (vegetative incompatibility) or het (heterokaryon incompatibility). We have genetically identified and characterised the first vic locus in the economically important, plant-pathogenic, necrotrophic fungus Botrytis cinerea. A bulked segregant approach coupled with whole genome Illumina sequencing of near-isogenic lines of B. cinerea was used to map a vic locus to a 60-kb region of the genome. Within that locus, we identified two adjacent, highly polymorphic open reading frames, Bcvic1 and Bcvic2, which encode predicted proteins that contain domain architectures implicated in vegetative incompatibility in other filamentous fungi. Bcvic1 encodes a predicted protein containing a putative serine esterase domain, a NACHT family of NTPases domain, and several Ankyrin repeats. Bcvic2 encodes a putative syntaxin protein containing a SNARE domain; such proteins typically function in vesicular transport. Deletion of Bcvic1 and Bcvic2 individually had no effect on vegetative incompatibility. However, deletion of the region containing both Bcvic1 and Bcvic2 resulted in mutant lines that were severely restricted in growth and showed loss of vegetative incompatibility. Complementation of these mutants by ectopic expression restored the growth and vegetative incompatibility phenotype, indicating that Bcvic1 and Bcvic2 are controlling vegetative incompatibility at this vic locus.


Assuntos
Proteínas Fúngicas , Genes Fúngicos , Sequência de Aminoácidos , Genes Fúngicos/genética , Proteínas Fúngicas/genética , Botrytis/genética
7.
PLoS Genet ; 16(5): e1008749, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32453742

RESUMO

Indonesia is the world's fourth most populous country, host to striking levels of human diversity, regional patterns of admixture, and varying degrees of introgression from both Neanderthals and Denisovans. However, it has been largely excluded from the human genomics sequencing boom of the last decade. To serve as a benchmark dataset of molecular phenotypes across the region, we generated genome-wide CpG methylation and gene expression measurements in over 100 individuals from three locations that capture the major genomic and geographical axes of diversity across the Indonesian archipelago. Investigating between- and within-island differences, we find up to 10.55% of tested genes are differentially expressed between the islands of Sumba and New Guinea. Variation in gene expression is closely associated with DNA methylation, with expression levels of 9.80% of genes correlating with nearby promoter CpG methylation, and many of these genes being differentially expressed between islands. Genes identified in our differential expression and methylation analyses are enriched in pathways involved in immunity, highlighting Indonesia's tropical role as a source of infectious disease diversity and the strong selective pressures these diseases have exerted on humans. Finally, we identify robust within-island variation in DNA methylation and gene expression, likely driven by fine-scale environmental differences across sampling sites. Together, these results strongly suggest complex relationships between DNA methylation, transcription, archaic hominin introgression and immunity, all jointly shaped by the environment. This has implications for the application of genomic medicine, both in critically understudied Indonesia and globally, and will allow a better understanding of the interacting roles of genomic and environmental factors shaping molecular and complex phenotypes.


Assuntos
Metilação de DNA , Etnicidade/genética , Interação Gene-Ambiente , Transcriptoma , Ilhas de CpG , Meio Ambiente , Epigênese Genética/fisiologia , Etnicidade/estatística & dados numéricos , Perfilação da Expressão Gênica/estatística & dados numéricos , Genética Populacional , Estudo de Associação Genômica Ampla/estatística & dados numéricos , Genômica/métodos , Humanos , Indonésia/epidemiologia , Ilhas/epidemiologia , Ilhas do Pacífico/epidemiologia , Linhagem , Fenótipo , Polimorfismo de Nucleotídeo Único , RNA-Seq
8.
BMC Biol ; 20(1): 144, 2022 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-35706021

RESUMO

BACKGROUND: Fungi exhibit astonishing diversity with multiple major phenotypic transitions over the kingdom's evolutionary history. As part of this process, fungi developed hyphae, adapted to land environments (terrestrialization), and innovated their sexual structures. These changes also helped fungi establish ecological relationships with other organisms (animals and plants), but the genomic basis of these changes remains largely unknown. RESULTS: By systematically analyzing 304 genomes from all major fungal groups, together with a broad range of eukaryotic outgroups, we have identified 188 novel orthogroups associated with major changes during the evolution of fungi. Functional annotations suggest that many of these orthogroups were involved in the formation of key trait innovations in extant fungi and are functionally connected. These innovations include components for cell wall formation, functioning of the spindle pole body, polarisome formation, hyphal growth, and mating group signaling. Innovation of mitochondria-localized proteins occurred widely during fungal transitions, indicating their previously unrecognized importance. We also find that prokaryote-derived horizontal gene transfer provided a small source of evolutionary novelty with such genes involved in key metabolic pathways. CONCLUSIONS: The overall picture is one of a relatively small number of novel genes appearing at major evolutionary transitions in the phylogeny of fungi, with most arising de novo and horizontal gene transfer providing only a small additional source of evolutionary novelty. Our findings contribute to an increasingly detailed portrait of the gene families that define fungal phyla and underpin core features of extant fungi.


Assuntos
Evolução Molecular , Fungos , Animais , Fungos/genética , Transferência Genética Horizontal , Filogenia , Plantas/genética
9.
BMC Biol ; 20(1): 246, 2022 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-36329441

RESUMO

BACKGROUND: Scab, caused by the biotrophic fungus Venturia inaequalis, is the most economically important disease of apples worldwide. During infection, V. inaequalis occupies the subcuticular environment, where it secretes virulence factors, termed effectors, to promote host colonization. Consistent with other plant-pathogenic fungi, many of these effectors are expected to be non-enzymatic proteins, some of which can be recognized by corresponding host resistance proteins to activate plant defences, thus acting as avirulence determinants. To develop durable control strategies against scab, a better understanding of the roles that these effector proteins play in promoting subcuticular growth by V. inaequalis, as well as in activating, suppressing, or circumventing resistance protein-mediated defences in apple, is required. RESULTS: We generated the first comprehensive RNA-seq transcriptome of V. inaequalis during colonization of apple. Analysis of this transcriptome revealed five temporal waves of gene expression that peaked during early, mid, or mid-late infection. While the number of genes encoding secreted, non-enzymatic proteinaceous effector candidates (ECs) varied in each wave, most belonged to waves that peaked in expression during mid-late infection. Spectral clustering based on sequence similarity determined that the majority of ECs belonged to expanded protein families. To gain insights into function, the tertiary structures of ECs were predicted using AlphaFold2. Strikingly, despite an absence of sequence similarity, many ECs were predicted to have structural similarity to avirulence proteins from other plant-pathogenic fungi, including members of the MAX, LARS, ToxA and FOLD effector families. In addition, several other ECs, including an EC family with sequence similarity to the AvrLm6 avirulence effector from Leptosphaeria maculans, were predicted to adopt a KP6-like fold. Thus, proteins with a KP6-like fold represent another structural family of effectors shared among plant-pathogenic fungi. CONCLUSIONS: Our study reveals the transcriptomic profile underpinning subcuticular growth by V. inaequalis and provides an enriched list of ECs that can be investigated for roles in virulence and avirulence. Furthermore, our study supports the idea that numerous sequence-unrelated effectors across plant-pathogenic fungi share common structural folds. In doing so, our study gives weight to the hypothesis that many fungal effectors evolved from ancestral genes through duplication, followed by sequence diversification, to produce sequence-unrelated but structurally similar proteins.


Assuntos
Ascomicetos , Malus , Ascomicetos/genética , Doenças das Plantas/microbiologia , Fungos do Gênero Venturia , Malus/genética , Malus/microbiologia
10.
Mol Biol Evol ; 38(11): 5107-5121, 2021 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-34383935

RESUMO

The settlement of Sahul, the lost continent of Oceania, remains one of the most ancient and debated human migrations. Modern New Guineans inherited a unique genetic diversity tracing back 50,000 years, and yet there is currently no model reconstructing their past population dynamics. We generated 58 new whole-genome sequences from Papua New Guinea, filling geographical gaps in previous sampling, specifically to address alternative scenarios of the initial migration to Sahul and the settlement of New Guinea. Here, we present the first genomic models for the settlement of northeast Sahul considering one or two migrations from Wallacea. Both models fit our data set, reinforcing the idea that ancestral groups to New Guinean and Indigenous Australians split early, potentially during their migration in Wallacea where the northern route could have been favored. The earliest period of human presence in Sahul was an era of interactions and gene flow between related but already differentiated groups, from whom all modern New Guineans, Bismarck islanders, and Indigenous Australians descend. The settlement of New Guinea was probably initiated from its southeast region, where the oldest archaeological sites have been found. This was followed by two migrations into the south and north lowlands that ultimately reached the west and east highlands. We also identify ancient gene flows between populations in New Guinea, Australia, East Indonesia, and the Bismarck Archipelago, emphasizing the fact that the anthropological landscape during the early period of Sahul settlement was highly dynamic rather than the traditional view of extensive isolation.


Assuntos
Etnicidade , Migração Humana , Austrália , Humanos , Papua Nova Guiné , Filogenia
11.
Plant Cell ; 31(7): 1466-1487, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31023841

RESUMO

The merging of distinct genomes, allopolyploidization, is a widespread phenomenon in plants. It generates adaptive potential through increased genetic diversity, but examples demonstrating its exploitation remain scarce. White clover (Trifolium repens) is a ubiquitous temperate allotetraploid forage crop derived from two European diploid progenitors confined to extreme coastal or alpine habitats. We sequenced and assembled the genomes and transcriptomes of this species complex to gain insight into the genesis of white clover and the consequences of allopolyploidization. Based on these data, we estimate that white clover originated ∼15,000 to 28,000 years ago during the last glaciation when alpine and coastal progenitors were likely colocated in glacial refugia. We found evidence of progenitor diversity carryover through multiple hybridization events and show that the progenitor subgenomes have retained integrity and gene expression activity as they traveled within white clover from their original confined habitats to a global presence. At the transcriptional level, we observed remarkably stable subgenome expression ratios across tissues. Among the few genes that show tissue-specific switching between homeologous gene copies, we found flavonoid biosynthesis genes strongly overrepresented, suggesting an adaptive role of some allopolyploidy-associated transcriptional changes. Our results highlight white clover as an example of allopolyploidy-facilitated niche expansion, where two progenitor genomes, adapted and confined to disparate and highly specialized habitats, expanded to a ubiquitous global presence after glaciation-associated allopolyploidization.


Assuntos
Genômica , Poliploidia , Trifolium/genética , Vias Biossintéticas/genética , Mapeamento Cromossômico , Flavonoides/biossíntese , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Geografia , Hibridização Genética , Camada de Gelo , Fatores de Tempo
12.
J Evol Biol ; 35(8): 1126-1137, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35830478

RESUMO

Hybridization is a route to speciation that occurs widely across the eukaryote tree of life. The success of allopolyploids (hybrid species with increased ploidy) and homoploid hybrids (with unchanged ploidy) is well documented. However, their formation and establishment is not straightforward, with a suite of near-instantaneous and longer term biological repercussions faced by the new species. Central to these challenges is the rewiring of gene regulatory networks following the merger of distinct genomes inherited from both parental species. Research on the evolution of hybrid gene expression has largely involved studies on a single hybrid species or a few gene families. Here, we present the first standardized transcriptome-wide study exploring the fates of genes following hybridization across three kingdoms: animals, plants and fungi. Within each kingdom, we pair an allopolyploid system with a closely related homoploid hybrid to decouple the influence of increased ploidy from genome merger. Genome merger, not changes in ploidy, has the greatest effect on posthybridization expression patterns across all study systems. Strikingly, we find that differentially expressed genes in parent species preferentially switch to more similar expression in hybrids across all kingdoms, likely as a consequence of regulatory trans-acting cross-talk within the hybrid nucleus. We also highlight the prevalence of gene loss or silencing among extremely differentially expressed genes in hybrid species across all kingdoms. These shared patterns suggest that the evolutionary process of hybridization leads to common high-level expression outcomes, regardless of the particular species or kingdom.


Assuntos
Hibridização Genética , Transcriptoma , Animais , Eucariotos/genética , Genoma , Ploidias
13.
Nature ; 538(7626): 510-513, 2016 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-27698418

RESUMO

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


Assuntos
Povo Asiático/genética , Genoma Humano/genética , Genômica , Migração Humana/história , Havaiano Nativo ou Outro Ilhéu do Pacífico/genética , Filogenia , Feminino , Genética Populacional , História Antiga , Humanos , Masculino , Nova Guiné/etnologia , Polinésia/etnologia , Tonga , Vanuatu
14.
Genomics ; 113(6): 4267-4275, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34774981

RESUMO

Epichloe fungi are endophytes of cool season grasses, both wild species and commercial cultivars, where they may exhibit mutualistic or pathogenic lifestyles. The Epichloe-grass symbiosis is of great interest to agricultural research for the fungal bioprotective properties conferred to host grasses but also serves as an ideal system to study the evolution of fungal plant-pathogens in natural environments. Here, we assembled and annotated gapless chromosome-level genomes of two pathogenic Epichloe sibling species. Both genomes have a bipartite genome organization, with blocks of highly syntenic gene-rich regions separated by blocks of AT-rich DNA. The AT-rich regions show an extensive signature of RIP (repeat-induced point mutation) and the expansion of this compartment accounts for the large difference in genome size between the two species. This study reveals how the rapid evolution of repeat structure can drive divergence between closely related taxa and highlights the evolutionary role of dynamic compartments in fungal genomes.


Assuntos
Epichloe , Cromossomos , Endófitos/genética , Epichloe/genética , Evolução Molecular , Genoma Fúngico , Poaceae/genética , Simbiose/genética
15.
Am J Hum Genet ; 102(1): 58-68, 2018 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-29304377

RESUMO

At the dawn of the second millennium, the expansion of the Indian Ocean trading network aligned with the emergence of an outward-oriented community along the East African coast to create a cosmopolitan cultural and trading zone known as the Swahili Corridor. On the basis of analyses of new genome-wide genotyping data and uniparental data in 276 individuals from coastal Kenya and the Comoros islands, along with large-scale genetic datasets from the Indian Ocean rim, we reconstruct historical population dynamics to show that the Swahili Corridor is largely an eastern Bantu genetic continuum. Limited gene flows from the Middle East can be seen in Swahili and Comorian populations at dates corresponding to historically documented contacts. However, the main admixture event in southern insular populations, particularly Comorian and Malagasy groups, occurred with individuals from Island Southeast Asia as early as the 8th century, reflecting an earlier dispersal from this region. Remarkably, our results support recent archaeological and linguistic evidence-based suggestions that the Comoros archipelago was the earliest location of contact between Austronesian and African populations in the Swahili Corridor.


Assuntos
Fluxo Gênico , Genética Populacional , Ásia , Austrália , Comores , Variação Genética , Humanos , Quênia , Polimorfismo de Nucleotídeo Único/genética
16.
Environ Microbiol ; 23(6): 3251-3264, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33939870

RESUMO

Fungi have evolved diverse lifestyles and adopted pivotal new roles in both natural ecosystems and human environments. However, the molecular mechanisms underlying their adaptation to new lifestyles are obscure. Here, we hypothesize that genes shared across all species with the same lifestyle, but absent in genera with alternative lifestyles, are crucial to that lifestyle. By analysing dozens of species within four genera in a fungal order, with each genus following a different lifestyle, we find that genus-specific genes are typically few in number. Notably, not all genus-specific genes appear to derive from de novo birth, with most instead reflecting recurrent loss across the fungi. Importantly, however, a subset of these genus-specific genes are shared by fungi with the same lifestyle in quite different evolutionary orders, thus supporting the view that some genus-specific genes are necessary for specific lifestyles. These lifestyle-specific genes are enriched for key functional classes and often exhibit specialized expression patterns. Genus-specific selection also contributes to lifestyle transitions, and is especially associated with intensity of pathogenesis. Our study, therefore, suggests that fungal adaptation to new lifestyles often requires just a small number of core genes, with gene turnover and positive selection playing complementary roles.


Assuntos
Hypocreales , Ecossistema , Fungos/genética , Genômica , Humanos , Estilo de Vida , Filogenia
17.
Environ Microbiol ; 23(4): 2116-2131, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33350014

RESUMO

Recent studies have identified key genes that control the symbiotic interaction between Epichloë festucae and Lolium perenne. Here we report on the identification of specific E. festucae genes that control host infection. Deletion of setB, which encodes a homologue of the H3K36 histone methyltransferase Set2/KMT3, reduced histone H3K36 trimethylation and led to severe defects in colony growth and hyphal development. The E. festucae ΔclrD mutant, which lacks the gene encoding the homologue of the H3K9 methyltransferase KMT1, displays similar developmental defects. Both mutants are completely defective in their ability to infect L. perenne. Alleles that complement the culture and plant phenotypes of both mutants also complement the histone methylation defects. Co-inoculation of either ΔsetB or ΔclrD with the wild-type strain enables these mutants to colonize the host. However, successful colonization by the mutants resulted in death or stunting of the host plant. Transcriptome analysis at the early infection stage identified four fungal candidate genes, three of which encode small-secreted proteins, that are differentially regulated in these mutants compared to wild type. Deletion of crbA, which encodes a putative carbohydrate binding protein, resulted in significantly reduced host infection rates by E. festucae.


Assuntos
Epichloe , Epichloe/genética , Epichloe/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Histonas/genética , Metiltransferases/genética , Poaceae , Simbiose/genética
18.
Environ Microbiol ; 23(9): 5289-5304, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33989447

RESUMO

Some Serratia entomophila isolates have been successfully exploited in biopesticides due to their ability to cause amber disease in larvae of the Aotearoa (New Zealand) endemic pasture pest, Costelytra giveni. Anti-feeding prophage and ABC toxin complex virulence determinants are encoded by a 153-kb single-copy conjugative plasmid (pADAP; amber disease-associated plasmid). Despite growing understanding of the S. entomophila pADAP model plasmid, little is known about the wider plasmid family. Here, we sequence and analyse mega-plasmids from 50 Serratia isolates that induce variable disease phenotypes in the C. giveni insect host. Mega-plasmids are highly conserved within S. entomophila, but show considerable divergence in Serratia proteamaculans with other variants in S. liquefaciens and S. marcescens, likely reflecting niche adaption. In this study to reconstruct ancestral relationships for a complex mega-plasmid system, strong co-evolution between Serratia species and their plasmids were found. We identify 12 distinct mega-plasmid genotypes, all sharing a conserved gene backbone, but encoding highly variable accessory regions including virulence factors, secondary metabolite biosynthesis, Nitrogen fixation genes and toxin-antitoxin systems. We show that the variable pathogenicity of Serratia isolates is largely caused by presence/absence of virulence clusters on the mega-plasmids, but notably, is augmented by external chromosomally encoded factors.


Assuntos
Besouros , Animais , Larva , Plasmídeos/genética , Prófagos/genética , Virulência/genética
19.
PLoS Genet ; 14(10): e1007467, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30356280

RESUMO

Structural features of genomes, including the three-dimensional arrangement of DNA in the nucleus, are increasingly seen as key contributors to the regulation of gene expression. However, studies on how genome structure and nuclear organisation influence transcription have so far been limited to a handful of model species. This narrow focus limits our ability to draw general conclusions about the ways in which three-dimensional structures are encoded, and to integrate information from three-dimensional data to address a broader gamut of biological questions. Here, we generate a complete and gapless genome sequence for the filamentous fungus, Epichloë festucae. We use Hi-C data to examine the three-dimensional organisation of the genome, and RNA-seq data to investigate how Epichloë genome structure contributes to the suite of transcriptional changes needed to maintain symbiotic relationships with the grass host. Our results reveal a genome in which very repeat-rich blocks of DNA with discrete boundaries are interspersed by gene-rich sequences that are almost repeat-free. In contrast to other species reported to date, the three-dimensional structure of the genome is anchored by these repeat blocks, which act to isolate transcription in neighbouring gene-rich regions. Genes that are differentially expressed in planta are enriched near the boundaries of these repeat-rich blocks, suggesting that their three-dimensional orientation partly encodes and regulates the symbiotic relationship formed by this organism.


Assuntos
DNA Fúngico/genética , Epichloe/genética , Regulação Fúngica da Expressão Gênica , Genoma Fúngico/genética , Sequências Repetitivas de Ácido Nucleico/genética , Sequência Rica em At/genética , DNA Fúngico/química , Proteínas Fúngicas/genética , Sequência Rica em GC/genética , Perfilação da Expressão Gênica/métodos , Hifas/genética , Análise de Sequência de DNA/métodos , Simbiose/genética
20.
BMC Med Inform Decis Mak ; 21(1): 281, 2021 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-34641870

RESUMO

BACKGROUND: An Informatics Consult has been proposed in which clinicians request novel evidence from large scale health data resources, tailored to the treatment of a specific patient. However, the availability of such consultations is lacking. We seek to provide an Informatics Consult for a situation where a treatment indication and contraindication coexist in the same patient, i.e., anti-coagulation use for stroke prevention in a patient with both atrial fibrillation (AF) and liver cirrhosis. METHODS: We examined four sources of evidence for the effect of warfarin on stroke risk or all-cause mortality from: (1) randomised controlled trials (RCTs), (2) meta-analysis of prior observational studies, (3) trial emulation (using population electronic health records (N = 3,854,710) and (4) genetic evidence (Mendelian randomisation). We developed prototype forms to request an Informatics Consult and return of results in electronic health record systems. RESULTS: We found 0 RCT reports and 0 trials recruiting for patients with AF and cirrhosis. We found broad concordance across the three new sources of evidence we generated. Meta-analysis of prior observational studies showed that warfarin use was associated with lower stroke risk (hazard ratio [HR] = 0.71, CI 0.39-1.29). In a target trial emulation, warfarin was associated with lower all-cause mortality (HR = 0.61, CI 0.49-0.76) and ischaemic stroke (HR = 0.27, CI 0.08-0.91). Mendelian randomisation served as a drug target validation where we found that lower levels of vitamin K1 (warfarin is a vitamin K1 antagonist) are associated with lower stroke risk. A pilot survey with an independent sample of 34 clinicians revealed that 85% of clinicians found information on prognosis useful and that 79% thought that they should have access to the Informatics Consult as a service within their healthcare systems. We identified candidate steps for automation to scale evidence generation and to accelerate the return of results. CONCLUSION: We performed a proof-of-concept Informatics Consult for evidence generation, which may inform treatment decisions in situations where there is dearth of randomised trials. Patients are surprised to know that their clinicians are currently not able to learn in clinic from data on 'patients like me'. We identify the key challenges in offering such an Informatics Consult as a service.


Assuntos
Fibrilação Atrial , Acidente Vascular Cerebral , Anticoagulantes/uso terapêutico , Fibrilação Atrial/tratamento farmacológico , Humanos , Informática , Encaminhamento e Consulta , Acidente Vascular Cerebral/tratamento farmacológico , Resultado do Tratamento , Varfarina/uso terapêutico
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