Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 57
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Am Nat ; 196(1): 9-28, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32552108

RESUMO

Hybrid zones occur as range boundaries for many animal taxa. One model for how hybrid zones form and stabilize is the tension zone model, a version of which predicts that hybrid zone widths are determined by a balance between random dispersal into hybrid zones and selection against hybrids. Here, we examine whether random dispersal and proxies for selection against hybrids (genetic distances between hybridizing pairs) can explain variation in hybrid zone widths across 131 hybridizing pairs of animals. We show that these factors alone can explain ∼40% of the variation in zone width among animal hybrid zones, with dispersal explaining far more of the variation than genetic distances. Patterns within clades were idiosyncratic. Genetic distances predicted hybrid zone widths particularly well for reptiles, while this relationship was opposite tension zone predictions in birds. Last, the data suggest that dispersal and molecular divergence set lower bounds on hybrid zone widths in animals, indicating that there are geographic restrictions on hybrid zone formation. Overall, our analyses reinforce the fundamental importance of dispersal in hybrid zone formation and more generally in the ecology of range boundaries.

2.
Curr Biol ; 30(11): 2026-2036.e3, 2020 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-32330422

RESUMO

Relative brain sizes in birds can rival those of primates, but large-scale patterns and drivers of avian brain evolution remain elusive. Here, we explore the evolution of the fundamental brain-body scaling relationship across the origin and evolution of birds. Using a comprehensive dataset sampling> 2,000 modern birds, fossil birds, and theropod dinosaurs, we infer patterns of brain-body co-variation in deep time. Our study confirms that no significant increase in relative brain size accompanied the trend toward miniaturization or evolution of flight during the theropod-bird transition. Critically, however, theropods and basal birds show weaker integration between brain size and body size, allowing for rapid changes in the brain-body relationship that set the stage for dramatic shifts in early crown birds. We infer that major shifts occurred rapidly in the aftermath of the Cretaceous-Paleogene mass extinction within Neoaves, in which multiple clades achieved higher relative brain sizes because of a reduction in body size. Parrots and corvids achieved the largest brains observed in birds via markedly different patterns. Parrots primarily reduced their body size, whereas corvids increased body and brain size simultaneously (with rates of brain size evolution outpacing rates of body size evolution). Collectively, these patterns suggest that an early adaptive radiation in brain size laid the foundation for subsequent selection and stabilization.

3.
Proc Natl Acad Sci U S A ; 117(9): 5059-5066, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-32041869

RESUMO

The radiation of angiosperms led to the emergence of the vast majority of today's plant species and all our major food crops. Their extraordinary diversification occurred in conjunction with the evolution of a more efficient vascular system for the transport of water, composed of vessel elements. The physical dimensions of these water-conducting specialized cells have played a critical role in angiosperm evolution; they determine resistance to water flow, influence photosynthesis rate, and contribute to plant stature. However, the genetic factors that determine their dimensions are unclear. Here we show that a previously uncharacterized gene, ENLARGED VESSEL ELEMENT (EVE), contributes to the dimensions of vessel elements in Populus, impacting hydraulic conductivity. Our data suggest that EVE is localized in the plasma membrane and is involved in potassium uptake of differentiating xylem cells during vessel development. In plants, EVE first emerged in streptophyte algae, but expanded dramatically among vessel-containing angiosperms. The phylogeny, structure and composition of EVE indicates that it may have been involved in an ancient horizontal gene-transfer event.

4.
New Phytol ; 224(3): 1252-1265, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31617595

RESUMO

If particular traits consistently affect rates of speciation and extinction, broad macroevolutionary patterns can be interpreted as consequences of selection at high levels of the biological hierarchy. Identifying traits associated with diversification rates is difficult because of the wide variety of characters under consideration and the statistical challenges of testing for associations from comparative phylogenetic data. Ploidy (diploid vs polyploid states) and breeding system (self-incompatible vs self-compatible states) are both thought to be drivers of differential diversification in angiosperms. We fit 29 diversification models to extensive trait and phylogenetic data in Solanaceae and investigate how speciation and extinction rate differences are associated with ploidy, breeding system, and the interaction between these traits. We show that diversification patterns in Solanaceae are better explained by breeding system and an additional unobserved factor, rather than by ploidy. We also find that the most common evolutionary pathway to polyploidy in Solanaceae occurs via direct breakdown of self-incompatibility by whole genome duplication, rather than indirectly via breakdown followed by polyploidization. Comparing multiple stochastic diversification models that include complex trait interactions alongside hidden states enhances our understanding of the macroevolutionary patterns in plant phylogenies.

5.
Genome Biol Evol ; 10(11): 2882-2898, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30239709

RESUMO

Genomic data have provided evidence of previously unknown ancient whole genome duplications (WGDs) and highlighted the role of WGDs in the evolution of many eukaryotic lineages. Ancient WGDs often are detected by examining distributions of synonymous substitutions per site (Ks) within a genome, or "Ks plots." For example, WGDs can be detected from Ks plots by using univariate mixture models to identify peaks in Ks distributions. We performed gene family simulation experiments to evaluate the effects of different Ks estimation methods and mixture models on our ability to detect ancient WGDs from Ks plots. The simulation experiments, which accounted for variation in substitution rates and gene duplication and loss rates across gene families, tested the effects of WGD age and gene retention rates following WGD on inferring WGDs from Ks plots. Our simulations reveal limitations of Ks plot analyses. Strict interpretations of mixture model analyses often overestimate the number of WGD events, and Ks plot analyses typically fail to detect WGDs when ≤10% of the duplicated genes are retained following the WGD. However, WGDs can accurately be characterized over an intermediate range of Ks. The simulation results are supported by empirical analyses of transcriptomic data, which also suggest that biases in gene retention likely affect our ability to detect ancient WGDs. Although our results indicate mixture model results should be interpreted with great caution, using node-averaged Ks estimates and applying more appropriate mixture models can improve the accuracy of detecting WGDs.


Assuntos
Modelos Genéticos , Poliploidia , Actinidia , Artemisia , Duplicação Gênica , Família Multigênica , Mutação Silenciosa , Transcriptoma
6.
Nat Ecol Evol ; 2(7): 1120-1127, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29915344

RESUMO

Organismal traits may evolve either gradually or in rapid pulses, but the relative importance of these modes in the generation of species differences is unclear. Additionally, while pulsed evolution is frequently assumed to be associated with speciation events, few studies have explicitly examined how the tempo of trait divergence varies with respect to different geographical phases of speciation, starting with geographic isolation and ending, in many cases, with spatial overlap (sympatry). Here we address these issues by combining divergence time estimates, trait measurements and geographic range data for 952 avian sister species pairs worldwide to examine the tempo and timing of trait divergence in recent speciation events. We show that patterns of divergence in key ecological traits are not gradual, but instead seem to follow a pattern of relative stasis interspersed with evolutionary pulses of varying magnitude. We also find evidence that evolutionary pulses generally precede sympatry, and that greater trait disparity is associated with sympatry. These findings suggest that early pulses of trait divergence promote subsequent transitions to sympatry, rather than occurring after sympatry has been established. Incorporating models with evolutionary pulses of varying magnitude into speciation theory may explain why some species pairs achieve rapid sympatry whereas others undergo prolonged geographical exclusion.


Assuntos
Aves/fisiologia , Especiação Genética , Traços de História de Vida , Animais , Simpatria
7.
Am J Bot ; 105(3): 549-564, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29730880

RESUMO

PREMISE OF THE STUDY: Many ecological and evolutionary processes shape the assembly of organisms into local communities from a regional pool of species. We analyzed phylogenetic and functional diversity to understand community assembly of the ferns of Florida at two spatial scales. METHODS: We built a phylogeny for 125 of the 141 species of ferns in Florida using five chloroplast markers. We calculated mean pairwise dissimilarity (MPD) and mean nearest taxon distance (MNTD) from phylogenetic distances and functional trait data for both spatial scales and compared the results to null models to assess significance. KEY RESULTS: Our results for over vs. underdispersion in functional and phylogenetic diversity differed depending on spatial scale and metric considered. At the county scale, MPD revealed evidence for phylogenetic overdispersion, while MNTD revealed phylogenetic and functional underdispersion, and at the conservation area scale, MPD revealed phylogenetic and functional underdispersion while MNTD revealed evidence only of functional underdispersion. CONCLUSIONS: Our results are consistent with environmental filtering playing a larger role at the smaller, conservation area scale. The smaller spatial units are likely composed of fewer local habitat types that are selecting for closely related species, with the larger-scale units more likely to be composed of multiple habitat types that bring together a larger pool of species from across the phylogeny. Several aspects of fern biology, including their unique physiology and water relations and the importance of the independent gametophyte stage of the life cycle, make ferns highly sensitive to local, microhabitat conditions.


Assuntos
Biodiversidade , Evolução Biológica , Ecologia , Ecossistema , Gleiquênias/genética , Filogenia , Adaptação Biológica , Cloroplastos , Florida , Células Germinativas Vegetais , Modelos Biológicos , Fenótipo , Fenômenos Fisiológicos Vegetais , Análise Espacial , Especificidade da Espécie , Água
8.
Appl Plant Sci ; 6(3): e1035, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29732265

RESUMO

Premise of the Study: Phenotypic data sets are necessary to elucidate the genealogy of life, but assembling phenotypic data for taxa across the tree of life can be technically challenging and prohibitively time consuming. We describe a semi-automated protocol to facilitate and expedite the assembly of phenotypic character matrices of plants from formal taxonomic descriptions. This pipeline uses new natural language processing (NLP) techniques and a glossary of over 9000 botanical terms. Methods and Results: Our protocol includes the Explorer of Taxon Concepts (ETC), an online application that assembles taxon-by-character matrices from taxonomic descriptions, and MatrixConverter, a Java application that enables users to evaluate and discretize the characters extracted by ETC. We demonstrate this protocol using descriptions from Araucariaceae. Conclusions: The NLP pipeline unlocks the phenotypic data found in taxonomic descriptions and makes them usable for evolutionary analyses.

9.
Appl Plant Sci ; 6(3): e1037, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29732267

RESUMO

Premise of the Study: Polyploidy has profound evolutionary consequences for land plants. Despite the availability of large phylogenetic and chromosomal data sets, estimating the rates of polyploidy and chromosomal evolution across the tree of life remains a challenging, computationally complex problem. We introduce the R package chromploid, which allows scientists to perform inference of chromosomal evolution rates across large phylogenetic trees. Methods and Results: chromploid is an open-source package in the R environment that calculates the likelihood function of models of chromosome evolution. Models of discrete character evolution can be customized using chromploid. We demonstrate the performance of the BiChroM model, testing for associations between rates of chromosome doubling (as a proxy for polyploidy) and a binary phenotypic character, within chromploid using simulations and empirical data from Solanum. In simulations, estimated chromosome-doubling rates were unbiased and the variance decreased with larger trees, but distinguishing small differences in rates of chromosome doubling, even from large data sets, remains challenging. In the Solanum data set, a custom model of chromosome number evolution demonstrated higher rates of chromosome doubling in herbaceous species compared to woody. Conclusions: chromploid enables researchers to perform robust likelihood-based inferences using complex models of chromosome number evolution across large phylogenies.

10.
Am J Bot ; 105(3): 614-622, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29603138

RESUMO

Providing science and society with an integrated, up-to-date, high quality, open, reproducible and sustainable plant tree of life would be a huge service that is now coming within reach. However, synthesizing the growing body of DNA sequence data in the public domain and disseminating the trees to a diverse audience are often not straightforward due to numerous informatics barriers. While big synthetic plant phylogenies are being built, they remain static and become quickly outdated as new data are published and tree-building methods improve. Moreover, the body of existing phylogenetic evidence is hard to navigate and access for non-experts. We propose that our community of botanists, tree builders, and informaticians should converge on a modular framework for data integration and phylogenetic analysis, allowing easy collaboration, updating, data sourcing and flexible analyses. With support from major institutions, this pipeline should be re-run at regular intervals, storing trees and their metadata long-term. Providing the trees to a diverse global audience through user-friendly front ends and application development interfaces should also be a priority. Interactive interfaces could be used to solicit user feedback and thus improve data quality and to coordinate the generation of new data. We conclude by outlining a number of steps that we suggest the scientific community should take to achieve global phylogenetic synthesis.


Assuntos
Disseminação de Informação , Gestão da Informação , Filogenia , Plantas/genética , DNA de Plantas , Humanos , Tecnologia da Informação , Análise de Sequência de DNA
11.
Evolution ; 71(5): 1138-1148, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28295270

RESUMO

Although numerous studies have surveyed the frequency with which different plant characters are associated with polyploidy, few statistical tools are available to identify the factors that potentially facilitate polyploidy. We describe a new probabilistic model, BiChroM, designed to associate the frequency of polyploidy and chromosomal change with a binary phenotypic character in a phylogeny. BiChroM provides a robust statistical framework for testing differences in rates of polyploidy associated with phenotypic characters along a phylogeny while simultaneously allowing for evolutionary transitions between character states. We used BiChroM to test whether polyploidy is more frequent in woody or herbaceous plants, based on tree with 4711 eudicot species. Although polyploidy occurs in woody species, rates of chromosome doubling were over six times higher in herbaceous species. Rates of single chromosome increases or decreases were also far higher in herbaceous than woody species. Simulation experiments indicate that BiChroM performs well with little to no bias and relatively little variance at a wide range of tree depths when trees have at least 500 taxa. Thus, BiChroM provides a first step toward a rigorous statistical framework for assessing the traits that facilitate polyploidy.


Assuntos
Evolução Biológica , Filogenia , Poliploidia , Cromossomos , Árvores
12.
PeerJ ; 4: e2187, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27547523

RESUMO

Phylogenetic trees can reveal the origins of endosymbiotic lineages of bacteria and detect patterns of co-evolution with their hosts. Although taxon sampling can greatly affect phylogenetic and co-evolutionary inference, most hypotheses of endosymbiont relationships are based on few available bacterial sequences. Here we examined how different sampling strategies of Gammaproteobacteria sequences affect estimates of the number of endosymbiont lineages in parasitic sucking lice (Insecta: Phthirapatera: Anoplura). We estimated the number of louse endosymbiont lineages using both newly obtained and previously sequenced 16S rDNA bacterial sequences and more than 42,000 16S rDNA sequences from other Gammaproteobacteria. We also performed parametric and nonparametric bootstrapping experiments to examine the effects of phylogenetic error and uncertainty on these estimates. Sampling of 16S rDNA sequences affects the estimates of endosymbiont diversity in sucking lice until we reach a threshold of genetic diversity, the size of which depends on the sampling strategy. Sampling by maximizing the diversity of 16S rDNA sequences is more efficient than randomly sampling available 16S rDNA sequences. Although simulation results validate estimates of multiple endosymbiont lineages in sucking lice, the bootstrap results suggest that the precise number of endosymbiont origins is still uncertain.

13.
Am J Bot ; 103(7): 1175-86, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27206462

RESUMO

PREMISE OF THE STUDY: Whole-genome duplications (WGDs) can rapidly increase genome size in angiosperms. Yet their mean genome size is not correlated with ploidy. We compared three hypotheses to explain the constancy of genome size means across ploidies. The genome downsizing hypothesis suggests that genome size will decrease by a given percentage after a WGD. The genome size threshold hypothesis assumes that taxa with large genomes or large monoploid numbers will fail to undergo or survive WGDs. Finally, the genome downsizing and threshold hypothesis suggests that both genome downsizing and thresholds affect the relationship between genome size means and ploidy. METHODS: We performed nonparametric bootstrap simulations to compare observed angiosperm genome size means among species or genera against simulated genome sizes under the three different hypotheses. We evaluated the hypotheses using a decision theory approach and estimated the expected percentage of genome downsizing. KEY RESULTS: The threshold hypothesis improves the approximations between mean genome size and simulated genome size. At the species level, the genome downsizing with thresholds hypothesis best explains the genome size means with a 15% genome downsizing percentage. In the genus level simulations, the monoploid number threshold hypothesis best explains the data. CONCLUSIONS: Thresholds of genome size and monoploid number added to genome downsizing at species level simulations explain the observed means of angiosperm genome sizes, and monoploid number is important for determining the genome size mean at the genus level.


Assuntos
Tamanho do Genoma/genética , Genoma de Planta/genética , Magnoliopsida/genética , Ploidias , Evolução Biológica , Simulação por Computador , Modelos Lineares
14.
Genome Biol Evol ; 8(4): 1023-37, 2016 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-26988251

RESUMO

Whole-genome duplications (WGDs) have helped shape the genomes of land plants, and recent evidence suggests that the genomes of all angiosperms have experienced at least two ancient WGDs. In plants, WGDs often are followed by rapid fractionation, in which many homeologous gene copies are lost. Thus, it can be extremely difficult to identify, let alone characterize, ancient WGDs. In this study, we use a new maximum likelihood estimator to test for evidence of ancient WGDs in land plants and estimate the fraction of new genes copies that are retained following a WGD using gene count data, the number of gene copies in gene families. We identified evidence of many putative ancient WGDs in land plants and found that the genome fractionation rates vary tremendously among ancient WGDs. Analyses of WGDs within Brassicales also indicate that background gene duplication and loss rates vary across land plants, and different gene families have different probabilities of being retained following a WGD. Although our analyses are largely robust to errors in duplication and loss rates and the choice of priors, simulations indicate that this method can have trouble detecting multiple WGDs that occur on the same branch, especially when the gene retention rates for ancient WGDs are very low. They also suggest that we should carefully evaluate evidence for some ancient plant WGD hypotheses.


Assuntos
Evolução Molecular , Duplicação Gênica , Genoma de Planta , Plantas/genética , Arabidopsis/genética , Simulação por Computador , Deleção de Genes , Magnoliopsida/genética , Modelos Genéticos , Filogenia , Poliploidia
16.
Proc Natl Acad Sci U S A ; 112(41): 12764-9, 2015 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-26385966

RESUMO

Reconstructing the phylogenetic relationships that unite all lineages (the tree of life) is a grand challenge. The paucity of homologous character data across disparately related lineages currently renders direct phylogenetic inference untenable. To reconstruct a comprehensive tree of life, we therefore synthesized published phylogenies, together with taxonomic classifications for taxa never incorporated into a phylogeny. We present a draft tree containing 2.3 million tips-the Open Tree of Life. Realization of this tree required the assembly of two additional community resources: (i) a comprehensive global reference taxonomy and (ii) a database of published phylogenetic trees mapped to this taxonomy. Our open source framework facilitates community comment and contribution, enabling the tree to be continuously updated when new phylogenetic and taxonomic data become digitally available. Although data coverage and phylogenetic conflict across the Open Tree of Life illuminate gaps in both the underlying data available for phylogenetic reconstruction and the publication of trees as digital objects, the tree provides a compelling starting point for community contribution. This comprehensive tree will fuel fundamental research on the nature of biological diversity, ultimately providing up-to-date phylogenies for downstream applications in comparative biology, ecology, conservation biology, climate change, agriculture, and genomics.


Assuntos
Classificação/métodos , Filogenia , Animais , Humanos
17.
BMC Evol Biol ; 15: 194, 2015 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-26377000

RESUMO

BACKGROUND: Although homologous recombination affects the efficacy of selection in populations, the pattern of recombination rate evolution and its effects on genome evolution across plants are largely unknown. Recombination can reduce genome size by enabling the removal of LTR retrotransposons, alter codon usage by GC biased gene conversion, contribute to complex histories of gene duplication and loss through tandem duplication, and enhance purifying selection on genes. Therefore, variation in recombination rate across species may explain some of the variation in genomic architecture as well as rates of molecular evolution. We used phylogenetic comparative methods to investigate the evolution of global meiotic recombination rate in angiosperms and its effects on genome architecture and selection at the molecular level using genetic maps and genome sequences from thirty angiosperm species. RESULTS: Recombination rate is negatively correlated with genome size, which is likely caused by the removal of LTR retrotransposons. After correcting recombination rates for euchromatin content, we also found an association between global recombination rate and average gene family size. This suggests a role for recombination in the preservation of duplicate genes or expansion of gene families. An analysis of the correlation between the ratio of nonsynonymous to synonymous substitution rates (dN/dS) and recombination rate in 3748 genes indicates that higher recombination rates are associated with an increased efficacy of purifying selection, suggesting that global recombination rates affect variation in rates of molecular evolution across distantly related angiosperm species, not just between populations. We also identified shifts in dN/dS for recombination proteins that are associated with shifts in global recombination rate across our sample of angiosperms. CONCLUSIONS: Although our analyses only reveal correlations, not mechanisms, and do not include potential covariates of recombination rate, like effective population size, they suggest that global recombination rates may play an important role in shaping the macroevolutionary patterns of gene and genome evolution in plants. Interspecific recombination rate variation is tightly correlated with genome size as well as variation in overall LTR retrotransposon abundances. Recombination may shape gene-to-gene variation in dN/dS between species, which might impact the overall gene duplication and loss rates.


Assuntos
Evolução Molecular , Magnoliopsida/genética , Evolução Biológica , DNA de Cloroplastos/genética , DNA de Plantas/genética , Genômica , Filogenia , Isolamento Reprodutivo
18.
Appl Plant Sci ; 3(2)2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25699217

RESUMO

UNLABELLED: • PREMISE OF THE STUDY: While numerous software packages enable scientists to evaluate molecular data and transform them for phylogenetic analyses, few such tools exist for phenomic data. We introduce MatrixConverter, a program that helps expedite and facilitate the transformation of raw phenomic character data into discrete character matrices that can be used in most evolutionary inference programs. • METHODS AND RESULTS: MatrixConverter is an open source program written in Java; a platform-independent binary executable, as well as sample data sets and a user's manual, are available at https://github.com/gburleigh/MatrixConverter/tree/master/distribution. MatrixConverter has a simple, intuitive user interface that enables the user to immediately begin scoring phenomic characters. We demonstrate the performance of MatrixConverter on a phenomic data set from cycads. • CONCLUSIONS: New technologies and software make it possible to obtain phenomic data from species across the tree of life, and MatrixConverter helps to transform these new data for evolutionary or ecological inference.

19.
PLoS Biol ; 13(1): e1002033, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25562316

RESUMO

Despite a large and multifaceted effort to understand the vast landscape of phenotypic data, their current form inhibits productive data analysis. The lack of a community-wide, consensus-based, human- and machine-interpretable language for describing phenotypes and their genomic and environmental contexts is perhaps the most pressing scientific bottleneck to integration across many key fields in biology, including genomics, systems biology, development, medicine, evolution, ecology, and systematics. Here we survey the current phenomics landscape, including data resources and handling, and the progress that has been made to accurately capture relevant data descriptions for phenotypes. We present an example of the kind of integration across domains that computable phenotypes would enable, and we call upon the broader biology community, publishers, and relevant funding agencies to support efforts to surmount today's data barriers and facilitate analytical reproducibility.


Assuntos
Estudos de Associação Genética , Animais , Biologia Computacional , Curadoria de Dados , Bases de Dados Factuais/normas , Interação Gene-Ambiente , Genômica , Humanos , Fenótipo , Padrões de Referência , Reprodutibilidade dos Testes , Terminologia como Assunto
20.
Mol Phylogenet Evol ; 84: 53-63, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25550149

RESUMO

Birds are the most diverse tetrapod class, with about 10,000 extant species that represent a remarkable evolutionary radiation in which most taxa arose during a short period of time. There has been a tremendous increase in the amount of molecular data available from birds, and more than two-thirds of these species have some sequence data available. Here we assembled these available sequence data from birds to estimate a large-scale avian phylogeny. We performed an unconstrained maximum likelihood analysis of a sparse supermatrix comprising 22 nuclear loci and seven mitochondrial regions from 6714 species. We inferred a phylogeny with a backbone remarkably similar to that obtained by detailed analyses of multigene datasets, yet with the addition of thousands of more taxa. All orders were monophyletic with generally high support. While most families and genera were well supported, a number of them, especially within the oscine passerines, had little or no support. This likely reflects problems with the circumscription of these genera and families. Our results indicate that the amount of sequence data currently available is sufficient to produce a robust estimate of the avian tree of life using current methods of inference. The availability of a tree that is unconstrained by prior information, with branch lengths that have a direct connection to the underlying data, should be useful for comparative methods, taxonomic revisions, and prioritizing taxa that should be targeted for additional data collection.


Assuntos
Evolução Biológica , Aves/classificação , Filogenia , Animais , Núcleo Celular/genética , Genes Mitocondriais , Funções Verossimilhança , Alinhamento de Sequência , Análise de Sequência de DNA
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA