. (2014) 'Rapid evolution of the cerebellum in humans and other great apes. ', Current biology., 24 (20). pp. 2440-2444. Further information on publisher's website:http://dx.doi.org/10. 1016/j.cub.2014.08.056 Publisher's copyright statement: NOTICE: this is the author's version of a work that was accepted for publication in Current Biology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reected in this document. Changes may have been made to this work since it was submitted for publication. A denitive version was subsequently published in Current Biology, 44, 20, 20 October 2014, 10.1016/j.cub.2014.056.
Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. We apply a method for estimating branch--specific evolutionary rates on a phylogeny faster rate of cerebellar relative to neocortical evolution than found on the rest of the tree (βape=1.12, t=5.61, p<0.0001), and this remains true even when comparing ape branches only to those other branches showing a relative increase (βape=1.29, t=7.33, p<0.0001). Rates of cerebellar relative to cortical evolution were up to 6 times faster on ape compared to non--ape branches (Table 1).Increased relative cerebellar rates are apparent on the ancestral ape branch ( Figure 2 and Table 1), suggesting that the initial impetus may have been the demands of below--branch locomotion and arboreal route--planning in large--bodied primates, just as predicted by one theory of ape cognitive evolution [7]. Although Povinelli & Cant [8] argued that this adaptive shift occurred after the split between lesser and 5 great ape lineages, fossil evidence suggests that it predated the split [8], potentially providing the initial impetus for cerebellar expansion, with gibbons (Hylobates) then showing a distinct adaptive shift into a smaller--bodied true brachiation niche. It was during the radiation of the great ape clade, however, that cerebellar expansion became notably rapid. Whilst there was a slight but significant (1.5--fold) increase in the relative rate along the branches leading to all apes, the average relative rate increase along branches within the great ape clade was 3.2--fold, including a 3.6--fold increase on the branch leading to Homo ( Figure 2 and Table 1).If the acceleration we observe in cerebellar relative to neocortical rates across ape lineages reflects directional selection for enlargement, cerebellum size should be significantly larger relati...