Instituto de Neurociencias, CSIC-UMH, Sant Joan d'Alacant, Spain.
Dev Neurobiol. 2022 Jul;82(5):428-453. doi: 10.1002/dneu.22891. Epub 2022 Jun 22.
The size of the cerebral cortex increases dramatically across amniotes, from reptiles to great apes. This is primarily due to different numbers of neurons and glial cells produced during embryonic development. The evolutionary expansion of cortical neurogenesis was linked to changes in neural stem and progenitor cells, which acquired increased capacity of self-amplification and neuron production. Evolution works via changes in the genome, and recent studies have identified a small number of new genes that emerged in the recent human and primate lineages, promoting cortical progenitor proliferation and increased neurogenesis. However, most of the mammalian genome corresponds to noncoding DNA that contains gene-regulatory elements, and recent evidence precisely points at changes in expression levels of conserved genes as key in the evolution of cortical neurogenesis. Here, we provide an overview of basic cellular mechanisms involved in cortical neurogenesis across amniotes, and discuss recent progress on genetic mechanisms that may have changed during evolution, including gene expression regulation, leading to the expansion of the cerebral cortex.
从爬行动物到类人猿，羊膜动物的大脑皮层体积显著增大。这主要是由于胚胎发育过程中产生的神经元和神经胶质细胞数量不同。皮质神经发生的进化扩张与神经干细胞和祖细胞的变化有关，这些细胞获得了自我扩增和神经元产生的能力。进化是通过基因组的变化来实现的，最近的研究已经确定了一小部分新基因出现在人类和灵长类动物的谱系中，这些基因促进了皮质祖细胞的增殖和神经发生的增加。然而，哺乳动物基因组的大部分对应于非编码 DNA，其中包含基因调控元件，最近的证据准确地指出，保守基因表达水平的变化是皮质神经发生进化的关键。在这里，我们概述了羊膜动物大脑皮层神经发生的基本细胞机制，并讨论了在进化过程中可能发生变化的遗传机制的最新进展，包括基因表达调控，这导致了大脑皮层的扩张。
