Maximum Parsimony (phylogenetics)

Maximum Parsimony (phylogenetics)

In general usage, parsimony means to be economical or thrifty. In biology, Parsimony is a non-parametric statistical method commonly used in computational phylogenetics for estimating phylogenies. Under parsimony, the preferred phylogenetic tree is the tree that requires the least evolutionary change to explain some observed data. "Maximum" parsimony refers to the condition of this preferred tree being the most parsimonious. It also refers to the methods associated with finding this maximally parsimonious tree. The basic idea was presented by Walter M. Fitch in 1971.

While evolution is not an entirely parsimonious process, it is generally thought that a simpler, more parsimonious chain of events are more likely to occur than more complicated, less parsimonious chains of events. Hence, parsimony (sensu lato) is typically sought in constructing phylogenetic trees, and in scientific explanation generally. However, complications in both actual evolutionary processes and in the methods used to reconstruct them make the science of phylogenetics difficult, relying more and more on advanced genomics and computational and statistical methods to complement traditional field research and morphological methods. In both principle and practice, parsimony helps guide this work.