{| style="float:right;" |- | |- | |} A phylogenetic tree is a tree (graph theory) showing the evolutionary interrelationships among various species or other entities that are believed to have a common descent. A ''phylogenetic tree'' is a form of a cladogram. In a phylogenetic tree, each node with descendants represents the most recent common ancestor of the descendants, and edge lengths correspond to time estimates. Each node in a phylogenetic tree is called a taxonomic unit. Internal nodes are generally referred to as Hypothetical Taxonomic Units (HTUs) as they cannot be directly observed. A ''rooted'' phylogenetic tree is a directed graph tree with a unique node corresponding to the (usually imputation (statistics)) most recent common ancestor of all the entities at the leaves of the tree. Figure 1 depicts a rooted phylogenetic tree, which has been colored according to the ''three-domain system'' (Carl Woese 1998). An ''unrooted'' phylogenetic tree is, loosely speaking, a tree derived from a rooted phylogenetic tree by omitting the root. More precisely, it is a forest of rooted phylogenetic trees depicted so that the roots are all linked. Figure 2 depicts an unrooted phylogenetic tree¹ for myosin, a gene family of proteins. Links to other pictures are given in the ''#Pictures on the web'' subsection below. There are three main methods of constructing phylogenetic trees: distance-based methods such as neighbour-joining, parsimony-based methods such as maximum parsimony, and character-based methods such as maximum likelihood or Bayesian inference. ==Caveats== *By their very nature, phylogenetic trees hide any hybridization and horizontal gene transfer (Woese 2002) that may have taken place. For these reasons, the proposed PhyloCode (see ''external links'' below) does not assume a tree structure. *The phylogenetic tree of a single gene or protein taken from a group of species often differs from similar trees for the same group of species, and therefore great care is needed in inferring phylogenetic relationships amongst species. *Trees that do not include extinct species must also be interpreted with care. ==See also== * dendrogram * endosymbiosis * phylogeny * evolutionary tree * taxonomy * tree structure ==Footnote== # T. Hodge, M.J.T.V. Cope (2000) ''A Myosin Family Tree''. Journal of Cell Science 113, 3353-3354. See also the Myosin external link below. ==References== *C.R. Woese, 1998. The Universal Ancestor. ''Proceedings of the National Academy of Sciences'' 95: 6854-6859. *C.R. Woese, 2002. On the evolution of cells. ''Proceedings of the National Academy of Sciences'' 99: 8742-8747. ==External links== === Pictures on the web === *[http://tolweb.org/tree/eukaryotes/accessory/treeoverview.html Phylogenetic Trees Based on 16s rDNA] *[http://www.ii.uib.no/~tim/treeOfLifeImagePage.html A 3D View] *[http://ycc.biosci.arizona.edu/nomenclature_system/fig1.html Human Y-Chromosome 2002 Phylogenetic Tree] ===General=== *[http://www.ohiou.edu/phylocode/index.html PhyloCode] *[http://www.mrc-lmb.cam.ac.uk/myosin/trees/trees.html A Multiple Alignment of 139 Myosin Sequences and a Phylogenetic Tree] *[http://tolweb.org/tree Tree of Life Web Project] *[http://www.the-scientist.com/yr2002/sep/research1_020916.html B.A. Maher, ''Uprooting the Tree of Life'', 16:18 (Sep. 16, 2002); subscription only] __NOTOC__ Phylogenetics vi:C%C3%A2y ph%C3%A1t sinh ch%E1%BB%A7ng lo%E1%BA%A1i
Very stylish. User:Wetman 10:07, 19 Nov 2003 (UTC)~ Some information on how phylogentic trees are computed from genome sequences would be nice. There doesn't seem to be awfully much material on that on the web. User:62.227.165.193 20:34, 10 Apr 2004 (UTC) ==Invitation== Work is currently in progress on a page entitled Views of Creationists and mainstream scientists compared. Also currently being worked upon is Wikipedia: NPOV (Comparison of views in science) giving guidelines for this type of page. It is meant to be a set of guidelines for NPOV in this setting. People knowledgable in many areas of science and the philosophy of science are greatly needed here. And all are needed to ensure the guidelines correctly represent NPOV in this setting. :) User:Barnaby dawson 22:09, 29 Dec 2004 (UTC)
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Words begining with Phylogenetic_tree:
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Phylogenetic tree
{| style="float:right;" |- | |- | |} A phylogenetic tree is a tree (graph theory) showing the evolutionary interrelationships among various species or other entities that are believed to have a common descent. A ''phylogenetic tree'' is a form of a cladogram. In a phylogenetic tree, each node with descendants represents the most recent common ancestor of the descendants, and edge lengths correspond to time estimates. Each node in a phylogenetic tree is called a taxonomic unit. Internal nodes are generally referred to as Hypothetical Taxonomic Units (HTUs) as they cannot be directly observed. A ''rooted'' phylogenetic tree is a directed graph tree with a unique node corresponding to the (usually imputation (statistics)) most recent common ancestor of all the entities at the leaves of the tree. Figure 1 depicts a rooted phylogenetic tree, which has been colored according to the ''three-domain system'' (Carl Woese 1998). An ''unrooted'' phylogenetic tree is, loosely speaking, a tree derived from a rooted phylogenetic tree by omitting the root. More precisely, it is a forest of rooted phylogenetic trees depicted so that the roots are all linked. Figure 2 depicts an unrooted phylogenetic tree¹ for myosin, a gene family of proteins. Links to other pictures are given in the ''#Pictures on the web'' subsection below. There are three main methods of constructing phylogenetic trees: distance-based methods such as neighbour-joining, parsimony-based methods such as maximum parsimony, and character-based methods such as maximum likelihood or Bayesian inference. ==Caveats== *By their very nature, phylogenetic trees hide any hybridization and horizontal gene transfer (Woese 2002) that may have taken place. For these reasons, the proposed PhyloCode (see ''external links'' below) does not assume a tree structure. *The phylogenetic tree of a single gene or protein taken from a group of species often differs from similar trees for the same group of species, and therefore great care is needed in inferring phylogenetic relationships amongst species. *Trees that do not include extinct species must also be interpreted with care. ==See also== * dendrogram * endosymbiosis * phylogeny * evolutionary tree * taxonomy * tree structure ==Footnote== # T. Hodge, M.J.T.V. Cope (2000) ''A Myosin Family Tree''. Journal of Cell Science 113, 3353-3354. See also the Myosin external link below. ==References== *C.R. Woese, 1998. The Universal Ancestor. ''Proceedings of the National Academy of Sciences'' 95: 6854-6859. *C.R. Woese, 2002. On the evolution of cells. ''Proceedings of the National Academy of Sciences'' 99: 8742-8747. ==External links== === Pictures on the web === *[http://tolweb.org/tree/eukaryotes/accessory/treeoverview.html Phylogenetic Trees Based on 16s rDNA] *[http://www.ii.uib.no/~tim/treeOfLifeImagePage.html A 3D View] *[http://ycc.biosci.arizona.edu/nomenclature_system/fig1.html Human Y-Chromosome 2002 Phylogenetic Tree] ===General=== *[http://www.ohiou.edu/phylocode/index.html PhyloCode] *[http://www.mrc-lmb.cam.ac.uk/myosin/trees/trees.html A Multiple Alignment of 139 Myosin Sequences and a Phylogenetic Tree] *[http://tolweb.org/tree Tree of Life Web Project] *[http://www.the-scientist.com/yr2002/sep/research1_020916.html B.A. Maher, ''Uprooting the Tree of Life'', 16:18 (Sep. 16, 2002); subscription only] __NOTOC__ Phylogenetics vi:C%C3%A2y ph%C3%A1t sinh ch%E1%BB%A7ng lo%E1%BA%A1i
Phylogenetic tree
Very stylish. User:Wetman 10:07, 19 Nov 2003 (UTC)~ Some information on how phylogentic trees are computed from genome sequences would be nice. There doesn't seem to be awfully much material on that on the web. User:62.227.165.193 20:34, 10 Apr 2004 (UTC) ==Invitation== Work is currently in progress on a page entitled Views of Creationists and mainstream scientists compared. Also currently being worked upon is Wikipedia: NPOV (Comparison of views in science) giving guidelines for this type of page. It is meant to be a set of guidelines for NPOV in this setting. People knowledgable in many areas of science and the philosophy of science are greatly needed here. And all are needed to ensure the guidelines correctly represent NPOV in this setting. :) User:Barnaby dawson 22:09, 29 Dec 2004 (UTC)
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YouTube.com videos better site than Turbo Tax 2007
