Evol Ecol Res 11: 991-1015 (2009) Full PDF if your library subscribes.
Inferring macro-evolutionary patterns using an adaptive peak model of evolution
Jeroen B. Smaers and Lucio Vinicius
Leverhulme Centre for Human Evolutionary Studies, Department of Biological Anthropology, University of Cambridge, Cambridge, UK
Correspondence: J.B. Smaers, Leverhulme Centre for Human Evolutionary Studies, Department of Biological Anthropology, University of Cambridge, The Henry Wellcome Building, Fitzwilliam Street, Cambridge CB2 1QH, UK.
Background: Currently available methods of ancestral reconstruction are built either on Brownian Motion (BM) or Ornstein-Uhlenbeck (OU) models of evolution. Results from these methods sometimes do not agree with the fossil record.
Aim: Develop a new method, the method of Independent Evolution (IE), built on an adaptive peak model of evolution.
Key assumptions: In evolution, population phenotypes are affected by the wandering adaptive peaks of adaptive surfaces. Branch-specific rates of evolution depend on weighted, relative distances between an ancestral adaptive peak and a new adaptive surface that descendant populations attempt to climb.
Methods: We defined an eight-step algorithm to incorporate the assumptions, and then applied it recursively for each node in the tree to produce the phylogenetic histories. We performed two studies: a simulation study of directional selection on particular branches in a model primate phylogeny, and a case study of primate brain and body size in which we reconstructed the ancestral states of primate brain sizes and body sizes and compared them with 28 fossil data points. In each study, we used strong inference – that is, we employed six different methods of ancestral reconstruction to determine how well each succeeds. Four of the methods of ancestral reconstruction are based on BM, one on the OU, and one is IE.
Results: The method based on an adaptive peak model of evolution (IE) significantly outperformed both BM-based and OU-based methods of ancestral reconstruction in the simulation study. Independent Evolution also yielded much more accurate estimates of ancestral (i.e. fossil) primate brain and body sizes than the other methods of ancestral reconstruction.
Keywords: adaptation, adaptive peak, ancestral reconstruction, Brownian motion, comparative method, Ornstein-Uhlenbeck, phylogenetic analysis.
DOWNLOAD A FREE, FULL PDF COPY
IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.
© 2009 Jeroen B. Smaers. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.
Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.
All copies of abstracts and articles must preserve their copyright notice without modification.