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THE ROLE OF HYPOTHESIZED DIRECTION OF CHARACTERS IN THE ESTIMATION OF EVOLUTIONARY HISTORY
Author(s) -
Meacham Christopher A.
Publication year - 1984
Publication title -
taxon
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 81
eISSN - 1996-8175
pISSN - 0040-0262
DOI - 10.2307/1222026
Subject(s) - character (mathematics) , cladistics , tree (set theory) , evolutionary biology , phylogenetic tree , state (computer science) , mathematics , biology , combinatorics , algorithm , genetics , geometry , gene
Summary The effect of directing characters on cladistic analysis is discussed. Characters can conflict because of the character state membership of the EUs, the ordering of character states, or direction. Conflicts of characters were analyzed in twenty‐three data sets containing a total of 1024 characters. At least 93 percent of character conflicts in these data sets were not due to incorrectly hypothesized direction. Most character conflicts are caused by similarities among EUs that are due to parallelisms or reversals that were not recognized by the systematise Arguments against a priori directing of characters are presented. It is recommended that an undirected analysis be performed first and that the undirected tree be directed subsequently.