BBL: Are you really sure that character isn't irreversible? Testing Dollo's Law with ancestral-state reconstruction on evolutionary trees.

SpeakerDavid L Swofford (NESCent)
SummaryWednesday,12:00 PM at NESCent, Ninth Street and Main Street, Erwin Mill Building, 2024 W. Main Street, Suite A200. For more information, call 919-668-4551. ABSTRACT: The reconstruction of ancestral states on evolutionary trees is now a standard method of making inferences about character evolution. Increasingly, ancestral-state reconstructions have been used to support arguments for unexpected violations of "Dollo's Law", including reacquisition of eyes and pigment in cave-adapted organisms, re-evolution of sexuality from parthenogenetic ancestors, and the reacquisition of wings in stick insects. Methods for inference of ancestral states have become increasingly sophisticated, with maximum-likelihood and Bayesian methods largely replacing earlier reliance on maximum parsimony. However, despite the apparent rigor of these stochastic-model approaches, a number of aspects of their application are unsatisfying. These include model misspecification and inadequate data for accurate model-parameter estimation. In this talk I will review a number of studies that have employed ancestral-state reconstruction methods, and present the results of simulation studies that attempt to answer the question of whether the conclusions from these studies can be trusted. Future directions that attempt to overcome the limitations of existing methods will be outlined (probably too vaguely).