Reconstructing the ups and downs of primate brain evolution: implications for adaptive hypotheses and Homo floresiensis.
Reconstructing the ups and downs of primate brain evolution: implications for adaptive hypotheses and Homo floresiensis.
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DOI：
10.1186/1741-7007-8-9
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发表时间：
2010-01-27
期刊：
影响因子：
5.4
通讯作者：
Mundy NI
中科院分区：
文献类型：
--
作者：
Montgomery SH;Capellini I;Barton RA;Mundy NI
大脑的大小是一个关键的适应性特征。人们通常认为，大脑体积的增加是灵长类动物的一般进化趋势，但最近的化石发现记录了某些谱系中大脑体积的减少，这提出了一个问题，即随着进化时间的推移，大脑质量增加的趋势有多普遍。我们提出了第一个系统的系统发育分析，旨在回答这个问题。我们使用37种现存和23种灭绝的灵长类动物物种和三种方法进行了三种特征（绝对脑质量，绝对体重，相对脑质量）的祖先状态重建：简约，最大似然和贝叶斯马尔可夫链蒙特卡罗。绝对和相对的脑质量通常随着进化时间的推移而增加，但身体质量没有。然而，绝对和相对脑质量下降沿着几个分支。将这些结果应用到有争议的弗洛雷斯人案例中，我们发现了一些场景，在这些场景下，弗洛雷斯人小大脑的进化似乎与沿着其他谱系观察到的模式一致，取决于体重和系统发育位置。我们的研究结果证实，大脑的扩张在灵长类动物进化的早期就开始了，并表明所有主要分支都发生了增长。只有在绝对质量的增加方面，人类谱系才显得特别引人注目，无论是质量的比例变化率还是相对大脑大小，在灵长类动物的进化史上，其他地方都有更大的扩张。然而，在所有主要分支中，脑质量的减少也发生在沿着分支，我们得出结论，虽然选择起到了扩大灵长类大脑的作用，但在某些谱系中，这种趋势已经逆转。需要进一步分析弗洛雷斯人的系统发育位置和更好的体重估计，以确认其小脑质量进化的可解释性。我们发现，对于我们的数据集，祖先状态重建的贝叶斯分析受化石数据的影响最小，这表明这种方法对于未来对化石记录较差的其他分类群的研究可能更可取。
Brain size is a key adaptive trait. It is often assumed that increasing brain size was a general evolutionary trend in primates, yet recent fossil discoveries have documented brain size decreases in some lineages, raising the question of how general a trend there was for brains to increase in mass over evolutionary time. We present the first systematic phylogenetic analysis designed to answer this question. We performed ancestral state reconstructions of three traits (absolute brain mass, absolute body mass, relative brain mass) using 37 extant and 23 extinct primate species and three approaches to ancestral state reconstruction: parsimony, maximum likelihood and Bayesian Markov-chain Monte Carlo. Both absolute and relative brain mass generally increased over evolutionary time, but body mass did not. Nevertheless both absolute and relative brain mass decreased along several branches. Applying these results to the contentious case of Homo floresiensis, we find a number of scenarios under which the proposed evolution of Homo floresiensis' small brain appears to be consistent with patterns observed along other lineages, dependent on body mass and phylogenetic position. Our results confirm that brain expansion began early in primate evolution and show that increases occurred in all major clades. Only in terms of an increase in absolute mass does the human lineage appear particularly striking, with both the rate of proportional change in mass and relative brain size having episodes of greater expansion elsewhere on the primate phylogeny. However, decreases in brain mass also occurred along branches in all major clades, and we conclude that, while selection has acted to enlarge primate brains, in some lineages this trend has been reversed. Further analyses of the phylogenetic position of Homo floresiensis and better body mass estimates are required to confirm the plausibility of the evolution of its small brain mass. We find that for our dataset the Bayesian analysis for ancestral state reconstruction is least affected by inclusion of fossil data suggesting that this approach might be preferable for future studies on other taxa with a poor fossil record.
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影响因子：
3.7
作者：
Barton, Robert A.
通讯作者：
Barton, Robert A.
影响因子：
3.3
作者：
Boerner, Martina;Krueger, Oliver
通讯作者：
Krueger, Oliver
影响因子：
3.7
作者：
Charnov, Eric L.;Berrigan, David
通讯作者：
Berrigan, David
DOI：
10.1098/rstb.1995.0076
发表时间：
1995-06-29
期刊：
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES B-BIOLOGICAL SCIENCES
影响因子：
--
作者：
BARTON, RA;PURVIS, A;HARVEY, PH
通讯作者：
HARVEY, PH
影响因子：
10.7
作者：
Ali, Farhan;Meier, Rudolf
通讯作者：
Meier, Rudolf