Bigger brains cycle faster before neurogenesis begins: a comparison of brain development between chickens and bobwhite quail
Bigger brains cycle faster before neurogenesis begins: a comparison of brain development between chickens and bobwhite quail
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DOI：
10.1098/rspb.2010.0811
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发表时间：
2010-11-22
影响因子：
4.7
通讯作者：
Striedter, Georg F.
中科院分区：
文献类型：
--
作者：
Charvet, Christine J.;Striedter, Georg F.
成年后的鸡脑是鹌鹑脑的两倍多。为了确定这种大脑大小的物种差异如何在发育过程中出现，我们研究了神经发生时间或细胞周期速率的差异是否解释了鸡和鹌鹑之间大脑大小的差异。具体而言，我们研究了神经事件（如神经发生发作）的时间从鸡和鹌鹑胚胎的Nissl染色切片。我们估计脑细胞周期率使用累积溴脱氧尿苷标记鸡和鹌鹑在胚胎天（艾德）2和ED 5。我们报告说，神经事件的时间是高度保守的鸡和鹌鹑之间，一旦时间表示为总潜伏期的百分比。在绝对时间上，鸡的神经发生比鹌鹑早。因此，神经事件计时不能解释鸡脑相对于鹌鹑脑的扩张。在ED 5时，两个物种之间的细胞周期速率也相似。然而，在ED 2，在神经发生开始之前，鸡的脑细胞周期比鹌鹑快。这些数据表明，鸡的大脑比鹌鹑大，主要是因为胚胎发育早期细胞周期速率的物种差异。
The chicken brain is more than twice as big as the bobwhite quail brain in adulthood. To determine how this species difference in brain size emerges during development, we examined whether differences in neurogenesis timing or cell cycle rates account for the disparity in brain size between chickens and quail. Specifically, we examined the timing of neural events (e.g. neurogenesis onset) from Nissl-stained sections of chicken and quail embryos. We estimated brain cell cycle rates using cumulative bromodeoxyuridine labelling in chickens and quail at embryonic day (ED) 2 and at ED5. We report that the timing of neural events is highly conserved between chickens and quail, once time is expressed as a percentage of overall incubation period. In absolute time, neurogenesis begins earlier in chickens than in quail. Therefore, neural event timing cannot account for the expansion of the chicken brain relative to the quail brain. Cell cycle rates are also similar between the two species at ED5. However, at ED2, before neurogenesis onset, brain cells cycle faster in chickens than in quail. These data indicate that chickens have a larger brain than bobwhite quail mainly because of species differences in cell cycle rates during early stages of embryonic development.