Phylogenetic place of guinea pigs: no support of the rodent-polyphyly hypothesis from maximum-likelihood analyses of multiple protein sequences

Graur et al.'s (1991) hypothesis that the guinea pig-like rodents have anevolutionary origin within mammals that is separate from that of otherrodents (the rodent-polyphyly hypothesis) was reexamined by themaximum-likelihood method for protein phylogeny, as well as by themaximum-parsimony and neighbor-joining methods. The overall evidence doesnot support Graur et al.'s hypothesis, which radically contradicts thetraditional view of rodent monophyly. This work demonstrates that we mustbe careful in choosing a proper method for phylogenetic inference and thatan argument based on a small data set (with respect to the length of thesequence and especially the number of species) may be unstable.