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Published byHarvey Mathews Modified over 9 years ago
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Character fit and consensus Thanks to Leandro Gaetano
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CHARACTER FIT
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Character fit Consistence Index (Ci) Retention Index (Ri) How well the data fit the tree(s)? Length (L)
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Length
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Consistency Index (ci); relative amount of homoplasy ci = m / s s = number of steps in the tree and m = character states-1 Charci 11/1 = 1 2 3 4 5½= 0,5 6 Character fit ci varies between 1 (no homoplasy) to values close to 0 (higher quantity of homoplasy)
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Consistency Index For the tree it is called ensemble consistency index; CI
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Ajuste de caracteres Consistency Index (ci): Problems Uninformative characters increment artificially the ci Negatively correlated with number of characters and of taxa. Not useful to compare trees with different number of terminals and characters
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Retention Index (ri) ri= (g-s)/(g-m) s= number of steps in the tree; m= number of states – 1; g= maximum number of steps that a character can have in the cladogram (number of taxa with state 0 or 1, whichever is the lower ri(3)= (3-1)/3-1)= 1 ri(6)= (2-2)/(2-1) = 0 Character fit This is for individual characters For the tree it is called ensemble retention index; RI ri varies from 1 (no homoplasy) to 0 (higher quantity of homoplasy)
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CONSENSUS
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Consensus Consensus tree is used to explore congruence or incongruence among the most parsimonious trees (also called fundamental trees) of a cladistic analysis
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Consensus Synthesis of information of most parsimonious trees Comparing different partitions of data For the calculation of branch support When is consensus tree neccesary?
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Consensus trees Compromise cladograms Take into account fundamental trees Strict consensus Semistrict, of majority and of Adam consensus Consensus
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Strict consensus ABCDEFGHIRepresentation of the group 2 3 2 2 1 2 1 2 1 1 1 1 1 Show groups obtained in all the fundamental cladograms. Lack of resolution is represented as polytomy Consensus
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Majority consensus Include groups that appears in the majority of the fundamental cladograms ABCDEFGHIRepresentation of the group 2 3 2 2 1 2 1 2 1 1 1 1 1 Consensus
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Semiestrict consensus Group represented in all the fundamental cladograms and groups no contradicted by any of these trees ABCDEFGHIRepresentation of the group 2 3 2 2 1 2 1 2 1 1 1 1 1 Consensus
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Consenso Conflictive taxa are relocated in a node common to all conflictive positions. Conflictive taxa remains separated by a polytomy Adam consensus ABCDEFGHIRepresentation of the group 2 3 2 2 1 2 1 2 1 1 1 1 1
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