scholarly journals A balance index for phylogenetic trees based on quartets

2018 ◽  
Author(s):  
Tomás M. Coronado ◽  
Arnau Mir ◽  
Francesc Rosselló ◽  
Gabriel Valiente
Keyword(s):  
Phylogenetic Trees ◽  
Expected Value ◽  
History Of ◽  
Number Of Leaves ◽  
Time Linear ◽  
Balance Index

AbstractWe define a new balance index for phylogenetic trees based on the symmetry of the evolutive history of every quartet of leaves. This index makes sense for polytomic trees and it can be computed in time linear in the number of leaves. We compute its maximum and minimum values for arbitrary and bifurcating trees, and we provide exact formulas for its expected value and variance for bifurcating trees under Ford’s α-model and Aldous’ β-model and for arbitrary trees under the α-γ-model.

scholarly journals Exploring and Reconstructing Ancestral Anatomies using Ontology-Informed Approaches

2019 ◽  
Vol 3 ◽  
Author(s):  
Sergei Tarasov ◽  
Istvan Miko ◽  
Matthew Yoder ◽  
Josef Uyeda
Keyword(s):  
Phylogenetic Trees ◽  
Character State ◽  
Ancestral Reconstruction ◽  
Anatomy Ontology ◽  
Insect Order ◽  
Ancestral Character State ◽  
Body Regions ◽  
Individual Traits ◽  
History Of ◽  
Complex Characters

Ancestral character state reconstruction has been long used to gain insight into the evolution of individual traits in organisms. However, organismal anatomies (= entire phenotypes) are not merely ensembles of individual traits, rather they are complex systems where traits interact with each other due to anatomical dependencies (when one trait depends on the presence of another trait) and developmental constraints. Comparative phylogenetics has been largely lacking a method for reconstructing the evolution of entire organismal anatomies or organismal body regions. Herein, we present a new approach named PARAMO (Phylogenetic Ancestral Reconstruction of Anatomy by Mapping Ontologies, Tarasov and Uyeda 2019) that takes into account anatomical dependencies and uses stochastic maps (i.e., phylogenetic trees with an instance of mapped evolutionary history of characters, Huelsenbeck et al. 2003) along with anatomy ontologies to reconstruct organismal anatomies. Our approach treats the entire phenotype or its component body regions as single complex characters and allows exploring and comparing phenotypic evolution at different levels of anatomical hierarchy. These complex characters are constructed by ontology-informed amalgamation of elementary characters (i.e., those coded in character matrix) using stochastic maps. In our approach, characters are linked with the terms from an anatomy ontology, which allows viewing them not just as an ensemble of character state tokens but as entities that have their own biological meaning provided by the ontology. This ontology-informed framework provides new opportunities for tracking phenotypic radiations and anatomical evolution of organisms, which we explore using a large dataset for the insect order Hymenoptera (sawflies, wasps, ants and bees).

scholarly journals The Evolutionary History of the Chymase Locus -a Locus Encoding Several of the Major Hematopoietic Serine Proteases

2021 ◽  
Vol 22 (20) ◽  
pp. 10975
Author(s):  
Srinivas Akula ◽  
Zhirong Fu ◽  
Sara Wernersson ◽  
Lars Hellman
Keyword(s):  
Mast Cell ◽  
T Cell ◽  
Serine Proteases ◽  
Phylogenetic Trees ◽  
Granzyme B ◽  
Large Family ◽  
Cathepsin G ◽  
Immune Functions ◽  
New Class ◽  
History Of

Several hematopoietic cells of the immune system store large amounts of proteases in cytoplasmic granules. The absolute majority of these proteases belong to the large family of chymotrypsin-related serine proteases. The chymase locus is one of four loci encoding these granule-associated serine proteases in mammals. The chymase locus encodes only four genes in primates, (1) the gene for a mast-cell-specific chymotryptic enzyme, the chymase; (2) a T-cell-expressed asp-ase, granzyme B; (3) a neutrophil-expressed chymotryptic enzyme, cathepsin G; and (4) a T-cell-expressed chymotryptic enzyme named granzyme H. Interestingly, this locus has experienced a number of quite dramatic expansions during mammalian evolution. This is illustrated by the very large number of functional protease genes found in the chymase locus of mice (15 genes) and rats (18 genes). A separate expansion has also occurred in ruminants, where we find a new class of protease genes, the duodenases, which are expressed in the intestinal region. In contrast, the opossum has only two functional genes in this locus, the mast cell (MC) chymase and granzyme B. This low number of genes may be the result of an inversion, which may have hindered unequal crossing over, a mechanism which may have been a major factor in the expansion within the rodent lineage. The chymase locus can be traced back to early tetrapods as genes that cluster with the mammalian genes in phylogenetic trees can be found in frogs, alligators and turtles, but appear to have been lost in birds. We here present the collected data concerning the evolution of this rapidly evolving locus, and how these changes in gene numbers and specificities may have affected the immune functions in the various tetrapod species.

scholarly journals treeWidget: a BioJS component to visualise phylogenetic trees

F1000Research ◽  
2014 ◽  
Vol 3 ◽  
pp. 49 ◽  
Author(s):  
Fabian Schreiber
Keyword(s):  
Phylogenetic Trees ◽  
Protein Domains ◽  
Gene Families ◽  
Sequence Information ◽  
Gene Duplications ◽  
Link Type ◽  
History Of ◽  
Conservation Patterns ◽  
Evolution Of Gene Families ◽  
The Web

Summary: Phylogenetic trees are widely used to represent the evolution of gene families. As the history of gene families can be complex (including lots of gene duplications), its visualisation can become a difficult task. A good/accurate visualisation of phylogenetic trees - especially on the web - allows easier understanding and interpretation of trees to help to reveal the mechanisms that shape the evolution of a specific set of gene/species. Here, I present treeWidget, a modular BioJS component to visualise phylogenetic trees on the web. Through its modularity, treeWidget can be easily customized to allow the display of sequence information, e.g. protein domains and alignment conservation patterns.Availability: http://github.com/biojs/biojs; http://dx.doi.org/10.5281/zenodo.7707

INFERRING PHYLOGENETIC RELATIONSHIPS AVOIDING FORBIDDEN ROOTED TRIPLETS

2006 ◽  
Vol 04 (01) ◽  
pp. 59-74 ◽  
Author(s):  
YING-JUN HE ◽  
TRINH N. D. HUYNH ◽  
JESPER JANSSON ◽  
WING-KIN SUNG
Keyword(s):  
Approximation Algorithms ◽  
Phylogenetic Tree ◽  
Phylogenetic Trees ◽  
Evolutionary History ◽  
Phylogenetic Network ◽  
Evolutionary Relationships ◽  
Large Set ◽  
Tree Network ◽  
History Of ◽  
Overlapping Sets

To construct a phylogenetic tree or phylogenetic network for describing the evolutionary history of a set of species is a well-studied problem in computational biology. One previously proposed method to infer a phylogenetic tree/network for a large set of species is by merging a collection of known smaller phylogenetic trees on overlapping sets of species so that no (or as little as possible) branching information is lost. However, little work has been done so far on inferring a phylogenetic tree/network from a specified set of trees when in addition, certain evolutionary relationships among the species are known to be highly unlikely. In this paper, we consider the problem of constructing a phylogenetic tree/network which is consistent with all of the rooted triplets in a given set [Formula: see text] and none of the rooted triplets in another given set [Formula: see text]. Although NP-hard in the general case, we provide some efficient exact and approximation algorithms for a number of biologically meaningful variants of the problem.

Visualizing Speciation in Artificial Cichlid Fish

2006 ◽  
Vol 12 (2) ◽  
pp. 243-257 ◽  
Author(s):  
Ross Clement
Keyword(s):  
Phylogenetic Tree ◽  
Phylogenetic Trees ◽  
Cichlid Fish ◽  
Natural Consequence ◽  
Open Problems ◽  
Visualization System ◽  
Low Level ◽  
Wide Range ◽  
Level Information ◽  
History Of

The Cichlid Speciation Project (CSP) is an ALife simulation system for investigating open problems in the speciation of African cichlid fish. The CSP can be used to perform a wide range of experiments that show that speciation is a natural consequence of certain biological systems. A visualization system capable of extracting the history of speciation from low-level trace data and creating a phylogenetic tree has been implemented. Unlike previous approaches, this visualization system presents a concrete trace of speciation, rather than a summary of low-level information from which the viewer can make subjective decisions on how speciation progressed. The phylogenetic trees are a more objective visualization of speciation, and enable automated collection and summarization of the results of experiments. The visualization system is used to create a phylogenetic tree from an experiment that models sympatric speciation.

scholarly journals Jumping through the hoops: the challenges of daffodil (Narcissus) classification

2019 ◽  
Vol 190 (4) ◽  
pp. 389-404 ◽  
Author(s):  
Kálmán Könyves ◽  
John David ◽  
Alastair Culham
Keyword(s):  
Dna Sequences ◽  
Phylogenetic Trees ◽  
Plastid Dna ◽  
Microsatellite Data ◽  
Population Sampling ◽  
Molecular Phylogenetic ◽  
History Of ◽  
Nuclear Microsatellite ◽  
Congruent Group ◽  
First Time

Abstract Hoop-petticoat daffodils are a morphologically congruent group comprised of two distinct lineages in molecular phylogenetic trees of Narcissus. It is possible that the morphological similarity is a product of both historic and current low-level gene flow between these lineages. For the first time, we report population sampling from across the entire range of distribution covering the Iberian Peninsula and Morocco. In total, 455 samples were collected from 59 populations. Plastid DNA sequences of matK and ndhF were generated alongside 11 microsatellite loci to permit comparison between plastid and nuclear lineage histories. The plastid DNA phylogenetic tree was highly congruent with previous molecular studies and supported the recognition of these two lineages of hoop-petticoat daffodils as separate sections. Assignment of samples to sections sometimes differed between plastid DNA and (nuclear) microsatellite data. In these cases, the taxa had previously been the focus of dissent in taxonomic placement based on morphology. These discrepancies could be explained by hybridization and introgression among the two lineages during the evolution of hoop-petticoat daffodils, and shows that placement of species in sections is dependent on the source of data used. This study underlines the complex evolutionary history of Narcissus and highlights the discrepancies between floral morphology and phylogeny, which provides a continuing challenge for the systematics of Narcissus.

scholarly journals Simultaneous Bayesian inference of phylogeny and molecular coevolution

2019 ◽  
Vol 116 (11) ◽  
pp. 5027-5036 ◽  
Author(s):  
Xavier Meyer ◽  
Linda Dib ◽  
Daniele Silvestro ◽  
Nicolas Salamin
Keyword(s):  
16S Rrna ◽  
Phylogenetic Trees ◽  
Organic Molecules ◽  
Evolutionary Process ◽  
Protein Coding ◽  
Rrna Molecule ◽  
Shared Ancestry ◽  
History Of ◽  
Dependent Site ◽  
Synthetic Datasets

Patterns of molecular coevolution can reveal structural and functional constraints within or among organic molecules. These patterns are better understood when considering the underlying evolutionary process, which enables us to disentangle the signal of the dependent evolution of sites (coevolution) from the effects of shared ancestry of genes. Conversely, disregarding the dependent evolution of sites when studying the history of genes negatively impacts the accuracy of the inferred phylogenetic trees. Although molecular coevolution and phylogenetic history are interdependent, analyses of the two processes are conducted separately, a choice dictated by computational convenience, but at the expense of accuracy. We present a Bayesian method and associated software to infer how many and which sites of an alignment evolve according to an independent or a pairwise dependent evolutionary process, and to simultaneously estimate the phylogenetic relationships among sequences. We validate our method on synthetic datasets and challenge our predictions of coevolution on the 16S rRNA molecule by comparing them with its known molecular structure. Finally, we assess the accuracy of phylogenetic trees inferred under the assumption of independence among sites using synthetic datasets, the 16S rRNA molecule and 10 additional alignments of protein-coding genes of eukaryotes. Our results demonstrate that inferring phylogenetic trees while accounting for dependent site evolution significantly impacts the estimates of the phylogeny and the evolutionary process.

scholarly journals Comparative Analysis of Calcium-Dependent Protein Kinase in Cucurbitaceae and Expression Studies in Watermelon

2019 ◽  
Vol 20 (10) ◽  
pp. 2527 ◽  
Author(s):  
Chunhua Wei ◽  
Ruimin Zhang ◽  
Xiaozhen Yang ◽  
Chunyu Zhu ◽  
Hao Li ◽  
...  
Keyword(s):  
Phylogenetic Trees ◽  
Expression Patterns ◽  
Gene Families ◽  
Structural Variations ◽  
Calcium Dependent ◽  
Plot Analysis ◽  
Expression Studies ◽  
History Of ◽  
Dependent Protein ◽  
Male Flowers

Both the calcium-dependent protein kinases (CDPKs) and CDPK-related kinases (CRKs) play numerous roles in plant growth, development, and stress response. Despite genome-wide identification of both families in Cucumis, comparative evolutionary and functional analysis of both CDPKs and CRKs in Cucurbitaceae remain unclear. In this study, we identified 128 CDPK and 56 CRK genes in total in six Cucurbitaceae species (C. lanatus, C. sativus, C. moschata, C. maxima, C. pepo, and L. siceraria). Dot plot analysis indicated that self-duplication of conserved domains contributed to the structural variations of two CDPKs (CpCDPK19 and CpCDPK27) in C. pepo. Using watermelon genome as reference, an integrated map containing 25 loci (16 CDPK and nine CRK loci) was obtained, 16 of which (12 CDPK and four CRK) were shared by all seven Cucurbitaceae species. Combined with exon-intron organizations, topological analyses indicated an ancient origination of groups CDPK IV and CRK. Moreover, the evolutionary scenario of seven modern Cucurbitaceae species could also be reflected on the phylogenetic trees. Expression patterns of ClCDPKs and ClCRKs were studied under different abiotic stresses. Some valuable genes were uncovered for future gene function exploration. For instance, both ClCDPK6 and its ortholog CsCDPK14 in cucumber could be induced by salinity, while ClCDPK6 and ClCDPK16, as well as their orthologs in Cucumis, maintained high expression levels in male flowers. Collectively, these results provide insights into the evolutionary history of two gene families in Cucurbitaceae, and indicate a subset of candidate genes for functional characterizations in the future.

scholarly journals Sterol and genomic analyses validate the sponge biomarker hypothesis

2016 ◽  
Vol 113 (10) ◽  
pp. 2684-2689 ◽  
Author(s):  
David A. Gold ◽  
Jonathan Grabenstatter ◽  
Alex de Mendoza ◽  
Ana Riesgo ◽  
Iñaki Ruiz-Trillo ◽  
...  
Keyword(s):  
Phylogenetic Trees ◽  
Duplication Event ◽  
Cambrian Explosion ◽  
Living Animal ◽  
Molecular Fossil ◽  
Molecular Fossils ◽  
Genomic Analyses ◽  
History Of ◽  
Salpingoeca Rosetta ◽  
Close Relatives

Molecular fossils (or biomarkers) are key to unraveling the deep history of eukaryotes, especially in the absence of traditional fossils. In this regard, the sterane 24-isopropylcholestane has been proposed as a molecular fossil for sponges, and could represent the oldest evidence for animal life. The sterane is found in rocks ∼650–540 million y old, and its sterol precursor (24-isopropylcholesterol, or 24-ipc) is synthesized today by certain sea sponges. However, 24-ipc is also produced in trace amounts by distantly related pelagophyte algae, whereas only a few close relatives of sponges have been assayed for sterols. In this study, we analyzed the sterol and gene repertoires of four taxa (Salpingoeca rosetta,Capsaspora owczarzaki,Sphaeroforma arctica, andCreolimax fragrantissima), which collectively represent the major living animal outgroups. We discovered that all four taxa lack C30sterols, including 24-ipc. By building phylogenetic trees for key enzymes in 24-ipc biosynthesis, we identified a candidate gene (carbon-24/28 sterol methyltransferase, orSMT) responsible for 24-ipc production. Our results suggest that pelagophytes and sponges independently evolved C30sterol biosynthesis through clade-specificSMTduplications. Using a molecular clock approach, we demonstrate that the relevant spongeSMTduplication event overlapped with the appearance of 24-isopropylcholestanes in the Neoproterozoic, but that the algalSMTduplication event occurred later in the Phanerozoic. Subsequently, pelagophyte algae and their relatives are an unlikely alternative to sponges as a source of Neoproterozoic 24-isopropylcholestanes, consistent with growing evidence that sponges evolved long before the Cambrian explosion ∼542 million y ago.

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