How brains are built: genetics and evolution.
How brains are built: genetics and evolution.
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大脑是如何构建的：遗传学和进化。
DOI：
10.1159/000347054
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Vallender,EricJ
中科院分区：
文献类型：
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作者：
Vallender,EricJ
进化通过种内变异进行。基因变异导致了我们看到的个体之间的差异，并驱使他们固执己见，无论是偶然的还是选择的，并导致新物种的出现。这种理解在很大程度上推动了我们目前对生物学的思考，并为选择性压力的统计测试奠定了基础。它使我们能够更好地理解很久以前在进化时间发生的过程，创造出我们今天在我们周围看到的多样化的物种和表型。当我们今天对大脑进行比较研究时，我们试图重建很久以前固定的进化变化。这可以通过关注物种之间的遗传差异来实现，但我们的方法，特别是在蛋白质编码区域之外的方法，仍处于初级阶段，目前还没有达到足够的统计能力。此外，将特定的功能效应归因于固定的变化可能是令人望而生畏的，即使它们被成功识别。通过关注最终实现遗传变化的表型，比较神经解剖学家可以了解造成物种之间这些差异的潜在机制。对于我们对大脑进化的理解，有两种学派占据主导地位，主要集中在大脑各区域之间的关系以及它们共同进化的程度。虽然存在于一个连续体上，马赛克方法支持大脑由大量独立进化的模块组成的想法，而协同进化方法只设想了少数几个。这些假说起源于跨物种的比较研究，对神经发育程序的分子进化具有重要意义。
Evolution operates through intraspecific variation. It takes the genetic variation responsible for the differences that we see between individuals and drives them to fixation, whether by chance or selection, and leads to the emergence of new species. This understanding drives much of our current thinking of biology and underlies the statistical tests of selective pressures. It allows us to better understand the processes that occurred long ago, in evolutionary time, to create the diverse array of species and phenotypes that we see around us today.When we do comparative studies of the brain today, we are attempting to reconstruct evolutionary changes long since fixed. This can be accomplished by focusing on the genetic differences between species, but our methodologies, especially outside of protein-coding regions, are still in their infancies and do not currently achieve sufficient statistical power. Besides, attributing specific functional effects to fixed changes can be daunting even if they are successfully identified. By focusing on the phenotype, the ultimate realization of the genetic change, comparative neuroanatomists can inform on the underlying mechanisms that created these differences between species. Two schools of thought have predominated for our understanding of brain evolution, focusing mainly on the relationship between regions of the brain and to what degree they coevolve. While existing on a continuum, the mosaic approach favors the idea that brains consist of a large number of independently evolving modules; the concerted evolution approach envisions just a few. Originating in comparative studies across species, these hypotheses have important implications for the molecular evolution of neurodevelopmental programs.