Geomolecular dating and the origin of placental mammals
Phillips, Matthew J. (2016) Geomolecular dating and the origin of placental mammals. Systematic Biology, 65(3), pp. 546-557.
In modern evolutionary divergence analysis the role of geological information extends beyond providing a timescale, to informing molecular rate variation across the tree. Here I consider the implications of this development. I use fossil calibrations to test the accuracy of models of molecular rate evolution for placental mammals, and reveal substantial misspecification associated with life history rate correlates. Adding further calibrations to reduce dating errors at specific nodes unfortunately tends to transfer underlying rate errors to adjacent branches. Thus, tight calibration across the tree is vital to buffer against rate model errors. I argue that this must include allowing maximum bounds to be tight when good fossil records permit, otherwise divergences deep in the tree will tend to be inflated by the interaction of rate errors and asymmetric confidence in minimum and maximum bounds. In the case of placental mammals I sought to reduce the potential for transferring calibration and rate model errors across the tree by focusing on well-supported calibrations with appropriately conservative maximum bounds. The resulting divergence estimates are younger than others published recently, and provide the long-anticipated molecular signature for the placental mammal radiation observed in the fossil record near the 66 Ma Cretaceous–Paleogene extinction event.
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|Item Type:||Journal Article|
|Keywords:||Cretaceous–Paleogene boundary, evolutionary rate, fossil calibration, life history, molecular dating, Placentalia|
|Subjects:||Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000) > EVOLUTIONARY BIOLOGY (060300) > Phylogeny and Comparative Analysis (060309)|
|Divisions:||Current > Schools > School of Earth, Environmental & Biological Sciences
Current > QUT Faculties and Divisions > Science & Engineering Faculty
|Deposited On:||27 Apr 2016 00:19|
|Last Modified:||21 Jun 2016 01:01|
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