Less rigid than phylogenetic trees, phylogenetic networks allow the description of a wider range of evolutionary events. In this note, we explain how to extend the rank invariants from phylogenetic trees to phylogenetic networks evolving under the general Markov model and the equivariant models.
Phylogenetic diversity indices such as the Fair Proportion (FP) index are frequently discussed as prioritization criteria in biodiversity conservation. They rank species according to their contribution to overall diversity by taking into account the unique and shared evolutionary history of each species as indicated by its placement in an underlying phylogenetic tree. Traditionally, phylogenetic trees were inferred from single genes and the resulting gene trees were assumed to be a valid estimate for the species tree, i.e., the "true" evolutionary history of the species under consideration. Ho…
'Tree-based' phylogenetic networks proposed by Francis and Steel have attracted much attention of theoretical biologists in the last few years. At the heart of the definitions of tree-based phylogenetic networks is the notion of 'support trees', about which there are numerous algorithmic problems that are important for evolutionary data analysis. Recently, Hayamizu (arXiv:1811.05849 [math.CO]) proved a structure theorem for tree-based phylogenetic networks and obtained linear-time and linear-delay algorithms for many basic problems on support trees, such as counting, optimisation, and enumerat…
Matrix representations and distance metrics for unlabeled ranked phylogenetic networks
University of Wisconsin-Madison(威斯康星大学麦迪逊分校);Wisconsin Institute for Discovery, University of Wisconsin-Madison(威斯康星发现研究所,威斯康星大学麦迪逊分校);Stanford University(斯坦福大学);Stanford Medicine(斯坦福医学院);Department of Plant Pathology, University of Wisconsin-Madison(威斯康星大学麦迪逊分校植物病理学系)
Planning for the protection of species often involves difficult choices about which species to prioritize, given constrained resources. One way of prioritizing species is to consider their "evolutionary distinctiveness", i.e. their relative evolutionary isolation on a phylogenetic tree. Several evolutionary isolation metrics or phylogenetic diversity indices have been introduced in the literature, among them the so-called Fair Proportion index (also known as the "evolutionary distinctiveness" score). This index apportions the total diversity of a tree among all leaves, thereby providing a simp…
We introduce and investigate the space of \emph{equidistant} $X$-\emph{cactuses}. These are rooted, arc weighted, phylogenetic networks with leaf set $X$, where $X$ is a finite set of species, and all leaves have the same distance from the root. The space contains as a subset the space of ultrametric trees on $X$ that was introduced by Gavryushkin and Drummond. We show that equidistant-cactus space is a CAT(0)-metric space which implies, for example, that there are unique geodesic paths between points. As a key step to proving this, we present a combinatorial result concerning \emph{ranked} ro…
By fixing all parameters in a phylogenetic likelihood model except for one branch length, one obtains a one-dimensional likelihood function. In this work, we introduce a mathematical framework to characterize the shapes of such one-dimensional phylogenetic likelihood functions. This framework is based on analyses of algebraic structures on the space of all frequency patterns with respect to a polynomial representation of the likelihood functions. Using this framework, we provide conditions under which the one-dimensional phylogenetic likelihood functions are guaranteed to have at most one stat…
A binary phylogenetic network on a taxon set $X$ is a rooted acyclic digraph in which the degree of each nonleaf node is three and its leaves (i.e.degree-one nodes) are uniquely labeled with the taxa of $X$. It is tree-child if each nonleaf node has at least one child of indegree one. A set of binary phylogenetic trees may or may not be simultaneously displayed in a binary tree-child network. Necessary conditions for multiple phylogenetic trees being simultaneously displayed in a tree-child network are given here. In particular, it is proved that any two phylogenetic trees can always simultane…
Tree-based networks are a class of phylogenetic networks that attempt to formally capture what is meant by "tree-like" evolution. A given non-tree-based phylogenetic network, however, might appear to be very close to being tree-based, or very far. In this paper, we formalise the notion of proximity to tree-based for unrooted phylogenetic networks, with a range of proximity measures. These measures also provide characterisations of tree-based networks. One measure in particular, related to the nearest neighbour interchange operation, allows us to define the notion of "tree-based rank". This pro…
Semialgebraic Conditions for Identifying Triangles in Phylogenetic Networks
New Jersey Institute of Technology(新泽理工学院);University of Wisconsin Madison(威斯康星大学麦迪逊分校);University of Hawai‘i at Mānoa(夏威夷大学马诺阿分校);The College of Wooster(伍斯特学院);North Carolina State University(北卡罗来纳州立大学)
Galled trees are studied as a recombination model in population genetics. This class of phylogenetic networks is generalized into tree-child, galled and reticulation-visible network classes by relaxing a structural condition imposed on galled trees. We count tree-child networks through enumerating their component graphs. Explicit counting formulas are also given for galled trees through their relationship to ordered trees, phylogenetic networks with few reticulations and phylogenetic networks in which the child of each reticulation is a leaf.
Invariants for complicated objects such as those arising in phylogenetics, whether they are invariants as matrices, polynomials, or other mathematical structures, are important tools for distinguishing and working with such objects. In this paper, we generalize a complete polynomial invariant on trees to a class of phylogenetic networks called separable networks, which will include orchard networks. Networks are becoming increasingly important for their ability to represent reticulation events, such as hybridization, in evolutionary history. We provide a function from the space of internally m…
Generalizing matrix representations to fully heterochronous ranked tree shapes
Fred Hutchinson Cancer Research Center(弗雷德·哈钦森癌症研究中心);Howard Hughes Medical Institute(霍华德·休斯医学研究所);Stanford University(斯坦福大学);Stanford School of Medicine(斯坦福医学院);University of Washington(华盛顿大学)
Modelling the substitution of nucleotides along a phylogenetic tree is usually done by a hidden Markov process. This allows to define a distribution of characters at the leaves of the trees and one might be able to obtain polynomial relationships among the probabilities of different characters. The study of these polynomials and the geometry of the algebraic varieties defined by them can be used to reconstruct phylogenetic trees. However, not all points in these algebraic varieties have biological sense. In this paper, we explore the extent to which adding semi-algebraic conditions arising fro…
Selective inference is considered for testing trees and edges in phylogenetic tree selection from molecular sequences. This improves the previously proposed approximately unbiased test by adjusting the selection bias when testing many trees and edges at the same time. The newly proposed selective inference $p$-value is useful for testing selected edges to claim that they are significantly supported if $p>1-α$, whereas the non-selective $p$-value is still useful for testing candidate trees to claim that they are rejected if $p<α$. The selective $p$-value controls the type-I error conditioned on…
Stockholm University(斯德哥尔摩大学);Leipzig University(莱比锡大学);University of Vienna(维也纳大学);Max Planck Institute for Mathematics in the Sciences(马普科学数学研究所);Universidad Nacional de Colombia(哥伦比亚国立大学);Santa Fe Institute(圣塔菲研究所)
Galled trees are studied as a recombination model in theoretic population genetics. This class of phylogenetic networks has been generalized to tree-child networks, normal networks and tree-based networks by relaxing a structural condition. Although these networks are simple, their topological structures have yet to be fully understood. It is well-known that all phylogenetic trees on $n$ taxa can be generated by the insertion of the $n$-th taxa to each edge of all the phylogenetic trees on $n-1$ taxa. We prove that all tree-child networks with $k$ reticulate nodes on $n$ taxa can be uniquely g…
Graph construction in QUBO-based recursive phylogenetic tree reconstruction
Graduate School of Media and Governance, Keio University(庆应义塾大学媒体治理研究生院);Human Biology-Microbiome-Quantum Research Center (WPI-Bio2Q), Keio University(庆应义塾大学生物学-微生物组-量子研究中心 (WPI-Bio2Q));Keio University Sustainable Quantum Artificial Intelligence Center (KSQAIC), Keio University(庆应义塾大学可持续量子人工智能中心 (KSQAIC))
Galled trees are widely studied as a recombination model in population genetics. This class of phylogenetic networks is generalized into galled networks by relaxing a structural condition. In this work, a linear recurrence formula is given for counting 1-galled networks, which are galled networks satisfying the condition that each reticulate node has only one leaf descendant. Since every galled network consists of a set of 1-galled networks stacked one on top of the other, a method is also presented to count and enumerate galled networks.
PhylaFlow: Hybrid Flow Matching in Billera-Holmes-Vogtmann Tree Space for Phylogenetic Inference
Eric and Wendy Schmidt Center, Broad Institute of MIT and Harvard(埃里克和wendy Schmidt中心,MIT和哈佛大学Broad研究所);Department of Biomedical Informatics, Harvard Medical School(哈佛医学院生物医学信息学系);Centennial High School(Centennial高中);Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard(传染病与微生物组计划,MIT和哈佛大学Broad研究所)