脊椎动物大脑信号传导中心的古老双胞胎体起源
Ariel M Pani1, Erin E Mullarkey, Jochanan Aronowicz
1Committee on Evolutionary Biology, The University of Chicago, 1025 East 57th Street, Chicago, Illinois 60637, USA.
Nature
|March 17, 2012
概括
对于大脑发育的古老遗传程序,与脊椎动物信号中心同类,在半弦动物中发现. 这表明这些复杂的基因网络在脊椎动物之前存在,并且在一些带状动物中消失了.
科学领域:
- 发育生物学是发展生物学.
- 进化生物学是进化的生物学.
- 神经科学是一个神经科学.
背景情况:
- 脊椎动物的神经外皮信号中心是大脑的模式.
- 这些中心在无脊椎带状动物中不存在或分离,这表明它们与脊椎动物一起进化.
- 之前的研究假定头带动物代表了祖先的带动物特征.
研究的目的:
- 为了研究脊椎动物大脑基因网络模式的进化起源.
- 为了测试脊椎动物信号传导中心的遗传程序是否存在于非带状脊椎动物中.
- 为了了解二胞体体格的祖先状态.
主要方法:
- 基因表达分析在半弦状物中的Saccoglossus kowalevskii.
- 比较基因组学和进化发育生物学方法.
- 研究了Fgf8/17/18,sfrp1/5,hh和wnt1.1的表达模式.
主要成果:
- 在S. kowalevskii中发现了三种脊椎动物信号中心 (前神经脊柱,内限区,静脉组织者) 的同源基因程序.
- 特定的基因 (Fgf8/17/18,sfrp1/5,hh,wnt1) 在半弦外皮中表现出类似于脊椎动物的表达模式.
- 同源的遗传机制调节外皮外纹在两种半弦动物和脊椎动物.
结论:
- 复杂的遗传调节网络用于身体模式存在于Deuterostome进化的早期.
- 这些网络可能早于脊椎动物的出现,并且不仅仅是在脊椎动物内部组装的.
- 信号中心的基因程序可能在一些弦状动物 (amphioxus, ascidians) 中退化,但在半弦状动物和脊椎动物中被保留和详细阐述.
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