BIS 2C Lecture 3: Bis 2C Lecture 3 - 1/10/18 (Estimating Trees with Parsimony)
17 Jan 2018
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Document Summary
Organisms that are more closely related to each other share a more recent common ancestor. Phylogenetic trees are inferred from the similarities that are observed among species or populations (terminal taxa). A tree is an hypothesis that can be tested with additional data. Traits or features of organisms are referred to as characters. To infer phylogenies we need characters that exhibit some variation i. e. characters that show different character states. For ease of data management we can apply does to the character states. Parsimony - we search for a tree of our taxa with the least amount of change in character states (aka the fewest steps) Steps are a change from one character state to another. The tree with the fewest amount of character changes is the most parsimonious tree. Outgroup method - you use information of the characters of one or more outgroups to determine whether their characteristics are ancestral or derived.
