scholarly journals Phylogenomics with paralogs

2015 ◽  
Vol 112 (7) ◽  
pp. 2058-2063 ◽  
Author(s):  
Marc Hellmuth ◽  
Nicolas Wieseke ◽  
Marcus Lechner ◽  
Hans-Peter Lenhof ◽  
Martin Middendorf ◽  
...  
Keyword(s):  
Phylogenetic Trees ◽  
Sequence Data ◽  
Gene Families ◽  
Data Sets ◽  
Gene Trees ◽  
Species Trees ◽  
Individual Gene ◽  
Genome Wide Data ◽  
Degree Of Certainty ◽  
Mathematical Phylogenetics

Phylogenomics heavily relies on well-curated sequence data sets that comprise, for each gene, exclusively 1:1 orthologos. Paralogs are treated as a dangerous nuisance that has to be detected and removed. We show here that this severe restriction of the data sets is not necessary. Building upon recent advances in mathematical phylogenetics, we demonstrate that gene duplications convey meaningful phylogenetic information and allow the inference of plausible phylogenetic trees, provided orthologs and paralogs can be distinguished with a degree of certainty. Starting from tree-free estimates of orthology, cograph editing can sufficiently reduce the noise to find correct event-annotated gene trees. The information of gene trees can then directly be translated into constraints on the species trees. Although the resolution is very poor for individual gene families, we show that genome-wide data sets are sufficient to generate fully resolved phylogenetic trees, even in the presence of horizontal gene transfer.

EXACT SOLUTIONS FOR SPECIES TREE INFERENCE FROM DISCORDANT GENE TREES

2013 ◽  
Vol 11 (05) ◽  
pp. 1342005 ◽  
Author(s):  
WEN-CHIEH CHANG ◽  
PAWEŁ GÓRECKI ◽  
OLIVER EULENSTEIN
Keyword(s):  
Exact Solutions ◽  
Gene Tree ◽  
Simulated Data ◽  
Gene Families ◽  
Species Tree ◽  
Data Sets ◽  
Gene Trees ◽  
Species Trees ◽  
Worst Case

Phylogenetic analysis has to overcome the grant challenge of inferring accurate species trees from evolutionary histories of gene families (gene trees) that are discordant with the species tree along whose branches they have evolved. Two well studied approaches to cope with this challenge are to solve either biologically informed gene tree parsimony (GTP) problems under gene duplication, gene loss, and deep coalescence, or the classic RF supertree problem that does not rely on any biological model. Despite the potential of these problems to infer credible species trees, they are NP-hard. Therefore, these problems are addressed by heuristics that typically lack any provable accuracy and precision. We describe fast dynamic programming algorithms that solve the GTP problems and the RF supertree problem exactly, and demonstrate that our algorithms can solve instances with data sets consisting of as many as 22 taxa. Extensions of our algorithms can also report the number of all optimal species trees, as well as the trees themselves. To better asses the quality of the resulting species trees that best fit the given gene trees, we also compute the worst case species trees, their numbers, and optimization score for each of the computational problems. Finally, we demonstrate the performance of our exact algorithms using empirical and simulated data sets, and analyze the quality of heuristic solutions for the studied problems by contrasting them with our exact solutions.

scholarly journals ASTRAL-Pro: Quartet-Based Species-Tree Inference despite Paralogy

2020 ◽  
Vol 37 (11) ◽  
pp. 3292-3307
Author(s):  
Chao Zhang ◽  
Celine Scornavacca ◽  
Erin K Molloy ◽  
Siavash Mirarab
Keyword(s):  
Simulated Data ◽  
Real Data ◽  
Single Copy ◽  
Species Tree ◽  
Alternative Methods ◽  
Data Sets ◽  
Gene Trees ◽  
Species Trees ◽  
Tree Inference ◽  
Genome Wide Data

Abstract Phylogenetic inference from genome-wide data (phylogenomics) has revolutionized the study of evolution because it enables accounting for discordance among evolutionary histories across the genome. To this end, summary methods have been developed to allow accurate and scalable inference of species trees from gene trees. However, most of these methods, including the widely used ASTRAL, can only handle single-copy gene trees and do not attempt to model gene duplication and gene loss. As a result, most phylogenomic studies have focused on single-copy genes and have discarded large parts of the data. Here, we first propose a measure of quartet similarity between single-copy and multicopy trees that accounts for orthology and paralogy. We then introduce a method called ASTRAL-Pro (ASTRAL for PaRalogs and Orthologs) to find the species tree that optimizes our quartet similarity measure using dynamic programing. By studying its performance on an extensive collection of simulated data sets and on real data sets, we show that ASTRAL-Pro is more accurate than alternative methods.

scholarly journals Phylogenetic signal is associated with the degree of variation in root-to-tip distances

2020 ◽  
Author(s):  
Mezzalina Vankan ◽  
Simon Y.W. Ho ◽  
Carolina Pardo-Diaz ◽  
David A. Duchêne
Keyword(s):  
Sequence Data ◽  
Phylogenetic Signal ◽  
Gene Tree ◽  
Phylogenetic Inference ◽  
Genomic Region ◽  
Published Data ◽  
Data Sets ◽  
Gene Trees ◽  
Species Trees ◽  
Data Set

AbstractThe phylogenetic information contained in sequence data is partly determined by the overall rate of nucleotide substitution in the genomic region in question. However, phylogenetic signal is affected by various other factors, such as heterogeneity in substitution rates across lineages. These factors might be able to predict the phylogenetic accuracy of any given gene in a data set. We examined the association between the accuracy of phylogenetic inference across genes and several characteristics of branch lengths in phylogenomic data. In a large number of published data sets, we found that the accuracy of phylogenetic inference from genes was consistently associated with their mean statistical branch support and variation in their gene tree root-to-tip distances, but not with tree length and stemminess. Therefore, a signal of constant evolutionary rates across lineages appears to be beneficial for phylogenetic inference. Identifying the causes of variation in root-to-tip lengths in gene trees also offers a potential way forward to increase congruence in the signal across genes and improve estimates of species trees from phylogenomic data sets.

scholarly journals Reconstructing the Phylogeny of Corynebacteriales while Accounting for Horizontal Gene Transfer

2020 ◽  
Vol 12 (4) ◽  
pp. 381-395
Author(s):  
Nilson Da Rocha Coimbra ◽  
Aristoteles Goes-Neto ◽  
Vasco Azevedo ◽  
Aïda Ouangraoua
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Phylogenetic Trees ◽  
Bacterial Species ◽  
Gene Tree ◽  
Gene Families ◽  
Common Mechanism ◽  
Species Trees ◽  
Bacterial Phylogeny ◽  
Homologous Genes

Abstract Horizontal gene transfer is a common mechanism in Bacteria that has contributed to the genomic content of existing organisms. Traditional methods for estimating bacterial phylogeny, however, assume only vertical inheritance in the evolution of homologous genes, which may result in errors in the estimated phylogenies. We present a new method for estimating bacterial phylogeny that accounts for the presence of genes acquired by horizontal gene transfer between genomes. The method identifies and corrects putative transferred genes in gene families, before applying a gene tree-based summary method to estimate bacterial species trees. The method was applied to estimate the phylogeny of the order Corynebacteriales, which is the largest clade in the phylum Actinobacteria. We report a collection of 14 phylogenetic trees on 360 Corynebacteriales genomes. All estimated trees display each genus as a monophyletic clade. The trees also display several relationships proposed by past studies, as well as new relevant relationships between and within the main genera of Corynebacteriales: Corynebacterium, Mycobacterium, Nocardia, Rhodococcus, and Gordonia. An implementation of the method in Python is available on GitHub at https://github.com/UdeS-CoBIUS/EXECT (last accessed April 2, 2020).

scholarly journals Linking Branch Lengths across Sets of Loci Provides the Highest Statistical Support for Phylogenetic Inference

2019 ◽  
Vol 37 (4) ◽  
pp. 1202-1210 ◽  
Author(s):  
David A Duchêne ◽  
K Jun Tong ◽  
Charles S P Foster ◽  
Sebastián Duchêne ◽  
Robert Lanfear ◽  
...  
Keyword(s):  
Empirical Data ◽  
Sequence Data ◽  
Branch Length ◽  
Data Sets ◽  
Gene Trees ◽  
Data Set ◽  
Branch Lengths ◽  
Statistical Support ◽  
Distinct Branch ◽  
Consistent Support

Abstract Evolution leaves heterogeneous patterns of nucleotide variation across the genome, with different loci subject to varying degrees of mutation, selection, and drift. In phylogenetics, the potential impacts of partitioning sequence data for the assignment of substitution models are well appreciated. In contrast, the treatment of branch lengths has received far less attention. In this study, we examined the effects of linking and unlinking branch-length parameters across loci or subsets of loci. By analyzing a range of empirical data sets, we find consistent support for a model in which branch lengths are proportionate between subsets of loci: gene trees share the same pattern of branch lengths, but form subsets that vary in their overall tree lengths. These models had substantially better statistical support than models that assume identical branch lengths across gene trees, or those in which genes form subsets with distinct branch-length patterns. We show using simulations and empirical data that the complexity of the branch-length model with the highest support depends on the length of the sequence alignment and on the numbers of taxa and loci in the data set. Our findings suggest that models in which branch lengths are proportionate between subsets have the highest statistical support under the conditions that are most commonly seen in practice. The results of our study have implications for model selection, computational efficiency, and experimental design in phylogenomics.

scholarly journals Recent Progress on Methods for Estimating and Updating Large Phylogenies

2021 ◽  
Author(s):  
Paul Zaharias ◽  
Tandy Warnow
Keyword(s):  
Sequence Data ◽  
Incomplete Lineage Sorting ◽  
Divide And Conquer ◽  
Estimation Methods ◽  
Gene Trees ◽  
Species Trees ◽  
Lineage Sorting ◽  
Multiple Sequence ◽  
Large Gene ◽  
Large Trees

With the increased availability of sequence data and even of fully sequenced and assembled genomes, phylogeny estimation of very large trees (even of hundreds of thousands of sequences) is now a goal for some biologists. Yet, the construction of these phylogenies is a complex pipeline presenting analytical and computational challenges, especially when the number of sequences is very large. In the last few years, new methods have been developed that aim to enable highly accurate phylogeny estimations on these large datasets, including divide-and-conquer techniques for multiple sequence alignment and/or tree estimation, methods that can estimate species trees from multi-locus datasets while addressing heterogeneity due to biological processes (e.g., incomplete lineage sorting and gene duplication and loss), and methods to add sequences into large gene trees or species trees. Here we present some of these recent advances and discuss opportunities for future improvements.

scholarly journals No-U-Turn sampling for phylogenetic trees

2021 ◽  
Author(s):  
Johannes Wahle
Keyword(s):  
Monte Carlo ◽  
Phylogenetic Trees ◽  
Sequence Data ◽  
Real Data ◽  
Correlated Data ◽  
Data Sets ◽  
Acceptance Probability ◽  
New States ◽  
Gradient Based ◽  
Efficient Exploration

The inference of phylogenetic trees from sequence data has become a staple in evolutionary research. Bayesian inference of such trees is predominantly based on the Metropolis-Hastings algorithm. For high dimensional and correlated data this algorithm is known to be inefficient. There are gradient based algorithms to speed up such inference. Building on recent research which uses gradient based approaches for the inference of phylogenetic trees in a Bayesian framework, I present an algorithm which is capable of performing No-U-Turn sampling for phylogenetic trees. As an extension to Hamiltonian Monte Carlo methods, No-U-Turn sampling comes with the same benefits, such as proposing distant new states with a high acceptance probability, but eliminates the need to manually tune hyper parameters. Evaluated on real data sets, the new sampler shows that it converges faster to the target distribution. The results also indicate that a higher number of topologies are traversed during sampling by the new algorithm in comparison to traditional Markov Chain Monte Carlo approaches. This new algorithm leads to a more efficient exploration of the posterior distribution of phylogenetic tree topologies.

scholarly journals A new (old) approach to genotype-based phylogenomic inference within species, with an example from the saguaro cactus (Carnegiea gigantea)

2020 ◽  
Author(s):  
Michael J. Sanderson ◽  
Alberto Búrquez ◽  
Dario Copetti ◽  
Michelle M. McMahon ◽  
Yichao Zeng ◽  
...  
Keyword(s):  
Large Scale ◽  
Sequence Data ◽  
Rooted Tree ◽  
Diploid Species ◽  
Morphological Characters ◽  
Data Sets ◽  
Genotype Data ◽  
Species Trees ◽  
Chromosome Inversion ◽  
Diploid Genotype

AbstractGenome sequence data are routinely being used to infer phylogenetic history within and between closely related diploid species, but few tree inference methods are specifically tailored to diploid genotype data. Here we re-examine the method of “polymorphism parsimony” (Inger 1967; Farris 1978; Felsenstein 1979), originally introduced to study morphological characters and chromosome inversion polymorphisms, to evaluate its utility for unphased diploid genotype data in large scale phylogenomic data sets. We show that it is equivalent to inferring species trees by minimizing deep coalescences—assuming an infinite sites model. Two potential advantages of this approach are scalability and estimation of a rooted tree. As with some other single nucleotide polymorphism (SNP) based methods, it requires thinning of data sets to statistically independent sites, and we describe a genotype-based test for phylogenetic independence. To evaluate this approach in genome scale data, we construct intraspecific phylogenies for 10 populations of the saguaro cactus using 200 Gbp of resequencing data, and then use these methods to test whether the population with highest genetic diversity corresponds to the root of the genotype trees. Results were highly congruent with the (unrooted) trees obtained using SVDquartets, a scalable alternative method of phylogenomic inference.

scholarly journals Species Tree Estimation from Genome-wide Data with Guenomu

2015 ◽  
Author(s):  
Leonardo de Oliveira Martins ◽  
David Posada
Keyword(s):  
Incomplete Lineage Sorting ◽  
Gene Tree ◽  
Gene Families ◽  
Species Tree ◽  
Gene Trees ◽  
Species Trees ◽  
Lineage Sorting ◽  
Multiple Sources ◽  
Reconstruction Methods ◽  
Tree Topologies

The history of particular genes and that of the species that carry them can be different due to different reasons. In particular, gene trees and species trees can truly differ due to well-known evolutionary processes like gene duplication and loss, lateral gene transfer or incomplete lineage sorting. Different species tree reconstruction methods have been developed to take this incongruence into account, which can be divided grossly into supertree and supermatrix approaches. Here, we introduce a new Bayesian hierarchical model that we have recently developed and implemented in the program Guenomu, that considers multiple sources of gene tree/species tree disagreement. Guenomu takes as input the posterior distributions of unrooted gene tree topologies for multiple gene families, in order to estimate the posterior distribution of rooted species tree topologies.

Estimating phylogenetic relationships despite discordant gene trees across loci: the species tree of a diverse species group of feather mites (Acari: Proctophyllodidae)

Parasitology ◽  
2011 ◽  
Vol 138 (13) ◽  
pp. 1750-1759 ◽  
Author(s):  
LACEY L. KNOWLES ◽  
PAVEL B. KLIMOV
Keyword(s):  
Phylogenetic Relationships ◽  
Species Interactions ◽  
Sequence Data ◽  
Species Group ◽  
Species Tree ◽  
Terminal Branch ◽  
Gene Trees ◽  
Species Trees ◽  
Feather Mites ◽  
History Of

SUMMARYWith the increased availability of multilocus sequence data, the lack of concordance of gene trees estimated for independent loci has focused attention on both the biological processes producing the discord and the methodologies used to estimate phylogenetic relationships. What has emerged is a suite of new analytical tools for phylogenetic inference – species tree approaches. In contrast to traditional phylogenetic methods that are stymied by the idiosyncrasies of gene trees, approaches for estimating species trees explicitly take into account the cause of discord among loci and, in the process, provides a direct estimate of phylogenetic history (i.e. the history of species divergence, not divergence of specific loci). We illustrate the utility of species tree estimates with an analysis of a diverse group of feather mites, the pinnatus species group (genus Proctophyllodes). Discord among four sequenced nuclear loci is consistent with theoretical expectations, given the short time separating speciation events (as evident by short internodes relative to terminal branch lengths in the trees). Nevertheless, many of the relationships are well resolved in a Bayesian estimate of the species tree; the analysis also highlights ambiguous aspects of the phylogeny that require additional loci. The broad utility of species tree approaches is discussed, and specifically, their application to groups with high speciation rates – a history of diversification with particular prevalence in host/parasite systems where species interactions can drive rapid diversification.

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