| 1. |
- Hyde, K. D., et al.
(författare)
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Global consortium for the classification of fungi and fungus-like taxa
- 2023
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Ingår i: MYCOSPHERE. - : Mushroom Research Foundation. - 2077-7000 .- 2077-7019. ; 14:1, s. 1960-2012
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Tidskriftsartikel (refereegranskat)abstract
- The Global Consortium for the Classification of Fungi and fungus-like taxa is an international initiative of more than 550 mycologists to develop an electronic structure for the classification of these organisms. The members of the Consortium originate from 55 countries/regions worldwide, from a wide range of disciplines, and include senior, mid-career and early-career mycologists and plant pathologists. The Consortium will publish a biannual update of the Outline of Fungi and fungus-like taxa, to act as an international scheme for other scientists. Notes on all newly published taxa at or above the level of species will be prepared and published online on the Outline of Fungi website (https://www.outlineoffungi.org/), and these will be finally published in the biannual edition of the Outline of Fungi and fungus-like taxa. Comments on recent important taxonomic opinions on controversial topics will be included in the biannual outline. For example, 'to promote a more stable taxonomy in Fusarium given the divergences over its generic delimitation', or 'are there too many genera in the Boletales?' and even more importantly, 'what should be done with the tremendously diverse 'dark fungal taxa?' There are undeniable differences in mycologists' perceptions and opinions regarding species classification as well as the establishment of new species. Given the pluralistic nature of fungal taxonomy and its implications for species concepts and the nature of species, this consortium aims to provide a platform to better refine and stabilise fungal classification, taking into consideration views from different parties. In the future, a confidential voting system will be set up to gauge the opinions of all mycologists in the Consortium on important topics. The results of such surveys will be presented to the International Commission on the Taxonomy of Fungi (ICTF) and the Nomenclature Committee for Fungi (NCF) with opinions and percentages of votes for and against. Criticisms based on scientific evidence with regards to nomenclature, classifications, and taxonomic concepts will be welcomed, and any recommendations on specific taxonomic issues will also be encouraged; however, we will encourage professionally and ethically responsible criticisms of others' work. This biannual ongoing project will provide an outlet for advances in various topics of fungal classification, nomenclature, and taxonomic concepts and lead to a community-agreed classification scheme for the fungi and fungus-like taxa. Interested parties should contact the lead author if they would like to be involved in future outlines.
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| 2. |
- Chen, Zhishan, et al.
(författare)
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Fine-mapping analysis including over 254 000 East Asian and European descendants identifies 136 putative colorectal cancer susceptibility genes
- 2024
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) have identified more than 200 common genetic variants independently associated with colorectal cancer (CRC) risk, but the causal variants and target genes are mostly unknown. We sought to fine-map all known CRC risk loci using GWAS data from 100,204 cases and 154,587 controls of East Asian and European ancestry. Our stepwise conditional analyses revealed 238 independent association signals of CRC risk, each with a set of credible causal variants (CCVs), of which 28 signals had a single CCV. Our cis-eQTL/mQTL and colocalization analyses using colorectal tissue-specific transcriptome and methylome data separately from 1299 and 321 individuals, along with functional genomic investigation, uncovered 136 putative CRC susceptibility genes, including 56 genes not previously reported. Analyses of single-cell RNA-seq data from colorectal tissues revealed 17 putative CRC susceptibility genes with distinct expression patterns in specific cell types. Analyses of whole exome sequencing data provided additional support for several target genes identified in this study as CRC susceptibility genes. Enrichment analyses of the 136 genes uncover pathways not previously linked to CRC risk. Our study substantially expanded association signals for CRC and provided additional insight into the biological mechanisms underlying CRC development.
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| 3. |
- Schaller, David, et al.
(författare)
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Corrigendum to “Best match graphs”
- 2021
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Ingår i: Journal of Mathematical Biology. - : Springer Science and Business Media LLC. - 0303-6812 .- 1432-1416. ; 82:6
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Two errors in the article Best Match Graphs (Geiß et al. in JMB 78: 2015–2057, 2019) are corrected. One concerns the tacit assumption that digraphs are sink-free, which has to be added as an additional precondition in Lemma 9, Lemma 11, Theorem 4. Correspondingly, Algorithm 2 requires that its input is sink-free. The second correction concerns an additional necessary condition in Theorem 9 required to characterize best match graphs. The amended results simplify the construction of least resolved trees for n-cBMGs, i.e., Algorithm 1. All other results remain unchanged and are correct as stated.
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| 4. |
- Bruckmann, Carmen, et al.
(författare)
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From modular decomposition trees to rooted median graphs
- 2022
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Ingår i: Discrete Applied Mathematics. - : Elsevier BV. - 0166-218X .- 1872-6771. ; 310, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- The modular decomposition of a symmetric map δ:X×X→Υ (or, equivalently, a set of pairwise-disjoint symmetric binary relations, a 2-structure, or an edge-colored undirected graph) is a natural construction to capture key features of δ in terms of a labeled tree. A map δ is explained by a vertex-labeled rooted tree (T,t) if the label δ(x,y) coincides with the label of the lowest common ancestor of x and y in T, i.e., if δ(x,y)=t(lca(x,y)). Only maps whose modular decomposition does not contain prime nodes, i.e., the symbolic ultrametrics, can be explained in this manner. Here we consider rooted median graphs as a generalization of (modular decomposition) trees to explain symmetric maps. We derive a linear-time algorithm that stepwisely resolves prime vertices in the modular decomposition tree to obtain a rooted and labeled median graph that explains a given symmetric map δ.
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| 5. |
- Hellmuth, Marc, 1980-, et al.
(författare)
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Clustering systems of phylogenetic networks
- 2023
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Ingår i: Theory in biosciences. - 1431-7613 .- 1611-7530. ; :142, s. 301-358
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Tidskriftsartikel (refereegranskat)abstract
- Rooted acyclic graphs appear naturally when the phylogenetic relationship of a set X of taxa involves not only speciations but also recombination, horizontal transfer, or hybridization that cannot be captured by trees. A variety of classes of such networks have been discussed in the literature, including phylogenetic, level-1, tree-child, tree-based, galled tree, regular, or normal networks as models of different types of evolutionary processes. Clusters arise in models of phylogeny as the sets C(v) of descendant taxa of a vertex v. The clustering system CN comprising the clusters of a network N conveys key information on N itself. In the special case of rooted phylogenetic trees, T is uniquely determined by its clustering system CT. Although this is no longer true for networks in general, it is of interest to relate properties of N and CN. Here, we systematically investigate the relationships of several well-studied classes of networks and their clustering systems. The main results are correspondences of classes of networks and clustering systems of the following form: If N is a network of type X, then CN satisfies Y, and conversely if C is a clustering system satisfying Y, then there is network N of type X such that C⊆CN.This, in turn, allows us to investigate the mutual dependencies between the distinct types of networks in much detail.
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| 6. |
- Hellmuth, Marc, et al.
(författare)
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Combining Orthology and Xenology Data in a Common Phylogenetic Tree
- 2021
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Ingår i: Advances in Bioinformatics and Computational Biology. - Cham : Springer. - 9783030918132 - 9783030918149 ; , s. 53-64
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Konferensbidrag (refereegranskat)abstract
- In mathematical phylogenetics, types of events in a gene tree T are formalized by vertex labels t(v) and set-valued edge labels λ(e). The orthology and paralogy relations between genes are a special case of a map δ on the pairs of leaves of T defined by δ(x,y)=q if the last common ancestor lca(x,y) of x and y is labeled by an event type q, e.g., speciation or duplication. Similarly, a map εε with m∈ε(x,y) if m∈λ(e) for at least one edge e along the path from lca(x,y) to y generalizes xenology, i.e., horizontal gene transfer. We show that a pair of maps (δ,ε) derives from a tree (T,t,λ) in this manner if and only if there exists a common refinement of the (unique) least-resolved vertex labeled tree (Tδ,tδ) that explains δ and the (unique) least-resolved edge labeled tree (Tε,λε) that explains ε (provided both trees exist). This result remains true if certain combinations of labels at incident vertices and edges are forbidden.
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| 7. |
- Hellmuth, Marc, et al.
(författare)
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Compatibility of partitions with trees, hierarchies, and split systems
- 2022
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Ingår i: Discrete Applied Mathematics. - : Elsevier BV. - 0166-218X .- 1872-6771. ; 314, s. 265-283
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Tidskriftsartikel (refereegranskat)abstract
- The question whether a partition P and a hierarchy H or a tree-like split system S are compatible naturally arises in a wide range of classification problems. In the setting of phylogenetic trees, one asks whether the sets of P coincide with leaf sets of connected components obtained by deleting some edges from the tree T that represents H or S, respectively. More generally, we ask whether a refinement T∗ of T exists such that T∗ and P are compatible in this sense. The latter is closely related to the question as to whether there exists a tree at all that is compatible with P. We report several characterizations for (refinements of) hierarchies and split systems that are compatible with (systems of) partitions. In addition, we provide a linear-time algorithm to check whether refinements of trees and a given partition are compatible. The latter problem becomes NP-complete but fixed-parameter tractable if a system of partitions is considered instead of a single partition. In this context, we also explore the close relationship of the concept of compatibility and so-called Fitch maps.
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| 8. |
- Hellmuth, Marc, et al.
(författare)
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Fitch Graph Completion
- 2023
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Ingår i: Lecture Notes in Computer Science. - 0302-9743 .- 1611-3349. ; , s. 225-237
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Tidskriftsartikel (refereegranskat)
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| 9. |
- Hellmuth, Marc, et al.
(författare)
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Generalized Fitch Graphs III : Symmetrized Fitch maps and Sets of Symmetric Binary Relations that are explained by Unrooted Edge-labeled Trees
- 2021
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Ingår i: Discrete Mathematics & Theoretical Computer Science. - : Centre pour la Communication Scientifique Directe (CCSD). - 1462-7264 .- 1365-8050. ; 23:1
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Tidskriftsartikel (refereegranskat)abstract
- Binary relations derived from labeled rooted trees play an import role in mathematical biology as formal models of evolutionary relationships. The (symmetrized) Fitch relation formalizes xenology as the pairs of genes separated by at least one horizontal transfer event. As a natural generalization, we consider symmetrized Fitch maps, that is, symmetric maps epsilon that assign a subset of colors to each pair of vertices in X and that can be explained by a tree T with edges that are labeled with subsets of colors in the sense that the color m appears in epsilon(x, y) if and only if m appears in a label along the unique path between x and y in T. We first give an alternative characterization of the monochromatic case and then give a characterization of symmetrized Fitch maps in terms of compatibility of a certain set of quartets. We show that recognition of symmetrized Fitch maps is NP-complete. In the restricted case where vertical bar epsilon(x, y)vertical bar <= 1 the problem becomes polynomial, since such maps coincide with class of monochromatic Fitch maps whose graph-representations form precisely the class of complete multi-partite graphs.
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| 10. |
- Korchmaros, Annachiara, et al.
(författare)
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Quasi-best match graphs
- 2023
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Ingår i: Discrete Applied Mathematics. - : Elsevier BV. - 0166-218X .- 1872-6771. ; 331, s. 104-125
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Tidskriftsartikel (refereegranskat)abstract
- Quasi-best match graphs (qBMGs) are a hereditary class of directed, properly vertex -colored graphs. They arise naturally in mathematical phylogenetics as a generalization of best match graphs, which formalize the notion of evolutionary closest relatedness of genes (vertices) in multiple species (vertex colors). They are explained by rooted trees whose leaves correspond to vertices. In contrast to BMGs, qBMGs represent only best matches at a restricted phylogenetic distance. We provide characterizations of qBMGs that give rise to polynomial-time recognition algorithms and identify the BMGs as the qBMGs that are color-sink-free. Furthermore, two-colored qBMGs are characterized as directed graphs satisfying three simple local conditions, two of which have appeared previously, namely bi-transitivity in the sense of Das et al. (2021) and a hierarchy-like structure of out-neighborhoods, i.e., N(x) n N(y) E {N(x), N(y), 0} for any two vertices x and y. Further results characterize qBMGs that can be explained by binary phylogenetic trees.
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