School of GeoSciences, University of Edinburgh, Grant Institute, Edinburgh, UK.
MRC Human Genetics Unit, MRC Institute of Genetics & Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, UK.
Nat Ecol Evol. 2021 Jun;5(6):808-819. doi: 10.1038/s41559-021-01431-1. Epub 2021 Apr 1.
Quantifying speciation times during human evolution is fundamental as it provides a timescale to test for the correlation between key evolutionary transitions and extrinsic factors such as climatic or environmental change. Here, we applied a total evidence dating approach to a hominin phylogeny to estimate divergence times under different topological hypotheses. The time-scaled phylogenies were subsequently used to perform ancestral state reconstructions of body mass and phylogenetic encephalization quotient (PEQ). Our divergence-time estimates are consistent with other recent studies that analysed extant species. We show that the origin of the genus Homo probably occurred between 4.30 and 2.56 million years ago. The ancestral state reconstructions show a general trend towards a smaller body mass before the emergence of Homo, followed by a trend towards a greater body mass. PEQ estimations display a general trend of gradual but accelerating encephalization evolution. The obtained results provide a rigorous temporal framework for human evolution.
量化人类进化过程中的物种形成时间至关重要，因为它提供了一个时间尺度，可以检验关键进化转折点与气候或环境变化等外在因素之间的相关性。在这里，我们应用了一种总证据年代测定方法来对人科的系统发育进行分析，以在不同的拓扑假设下估计分歧时间。随后，使用时间标度的系统发育进行体重和系统发生神经商（PEQ）的祖先状态重建。我们的分歧时间估计与其他最近分析现存物种的研究结果一致。我们表明，人属的起源可能发生在 430 万至 256 万年前之间。祖先状态重建显示出在人属出现之前，体重普遍呈下降趋势，随后呈上升趋势。PEQ 估计显示出逐渐但加速的脑进化的总体趋势。所得结果为人属进化提供了严格的时间框架。
