The evolution of eccrine sweat glands in human and nonhuman primates
The evolution of eccrine sweat glands in human and nonhuman primates
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DOI：
10.1016/j.jhevol.2017.12.003
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发表时间：
2018-04-01
影响因子：
3.2
通讯作者：
Kamilar, Jason M.
中科院分区：
文献类型：
--
作者：
Best, Andrew;Kamilar, Jason M.
出汗对大多数哺乳动物来说是一种不寻常的体温调节策略，但对人类至关重要。这种特征通常被假设是人类祖先从森林迁移到温暖干燥的开放环境的结果。由于软组织性状通常不会改变，因此这种想法很难测试。因此，我们使用比较的方法来检查15个外分泌腺性状从35个灵长类物种。对于每个性状，我们测量了系统发育信号，测试了三个进化模型来解释性状变异，并使用系统发育模型来研究性状如何随气候变量而变化。性状中的系统发育信号变化很大，其中两个性状表现出最高值是身体上的腺体分布和身体上的外分泌腺体与顶泌腺体的百分比。在大多数性状的变化是最好的解释了奥恩斯坦-乌伦贝克模型表明自然选择的重要性。气候强烈地预测了两个特征。首先，物种与高外泌腺糖原含量的栖息地表现出温暖的温度和低降雨量。第二，增加毛细作用的物种与高温有关。糖原是一种主要的能量基质，为外分泌腺中的汗液产生和钠重吸收提供动力，并且增加的毛细作用允许更多的氧气、葡萄糖和电解质输送。因此，我们的研究结果是自然选择的证据增加出汗能力的灵长类动物的体表外分泌腺生活在炎热和干燥的气候。我们认为，增加糖原含量和毛细作用的选择可能是人类体温调节出汗能力最初增加的一部分。(C)2017爱思唯尔有限公司版权所有
Sweating is an unusual thermoregulatory strategy for most mammals, yet is critical for humans. This trait is commonly hypothesized to result from human ancestors moving from a forest to a warmer and drier open environment. As soft tissue traits do not typically fossilize, this idea has been difficult to test. Therefore, we used a comparative approach to examine 15 eccrine gland traits from 35 primate species. For each trait we measured phylogenetic signal, tested three evolutionary models to explain trait variation, and used phylogenetic models to examine how traits varied in response to climate variables. Phylogenetic signal in traits varied substantially, with the two traits exhibiting the highest values being gland distribution on the body and percent eccrine vs. apocrine glands on the body. Variation in most traits was best explained by an Ornstein-Uhlenbeck model suggesting the importance of natural selection. Two traits were strongly predicted by climate. First, species with high eccrine gland glycogen content were associated with habitats exhibiting warm temperatures and low rainfall. Second, species with increased capillarization were associated with high temperature. Glycogen is a primary energy substrate powering sweat production and sodium reabsorption in the eccrine gland, and increased capillarization permits greater oxygen, glucose and electrolyte delivery. Thus, our results are evidence of natural selection for increased sweating capacity in primate species with body surface eccrine glands living in hot and dry climates. We suggest that selection for increased glycogen content and capillarization may have been part of initial increases in hominin thermoregulatory sweating capacity. (C) 2017 Elsevier Ltd. All rights reserved.