Abstract:
The debate about what causes the generation of form and structure in embryological development goes back to antiquity. Most recently, it has focused on the divergent views as to whether the generation of patterns and form in development is a largely self-organized process or is mainly determined by the genome, in particular, complex developmental gene regulatory processes. This paper presents and analyzes pertinent models of pattern formation and form generation in a developing organism in the past and the present, with a special emphasis on Alan Turing\'s 1952 reaction-diffusion model. I first draw attention to the fact that Turing\'s paper remained, at first, without a noticeable impact on the community of biologists because purely physical-chemical models were unable to explain embryological development and often also simple repetitive patterns. I then show that from the year 2000 and onwards, Turing\'s 1952 paper was increasingly cited also by biologists. The model was updated to include gene products and now seemed able to account for the generation of biological patterns, though discrepancies between models and biological reality remained. I then point out Eric Davidson\'s successful theory of early embryogenesis based on gene-regulatory network analysis and its mathematical modeling that not only was able to provide a mechanistic and causal explanation for gene regulatory events controlling developmental cell fate specification but, unlike reaction-diffusion models, also addressed the effects of evolution and organisms\' longstanding developmental and species stability. The paper concludes with an outlook on further developments of the gene regulatory network model.
摘要:
关于胚胎发育中形式和结构产生的原因的争论可以追溯到古代。最近,它集中在关于发育中模式和形式的产生是一个很大程度上自我组织的过程还是主要由基因组决定的不同观点上,特别是,复杂的发育基因调控过程。本文介绍和分析了过去和现在在发育中的生物中模式形成和形式产生的相关模型,特别强调了艾伦·图灵1952年的反应扩散模型。我首先提请注意图灵的论文仍然存在,首先,对生物学家群体没有明显的影响,因为纯粹的物理化学模型无法解释胚胎发育,而且通常也无法解释简单的重复模式。然后我证明从2000年起,图灵1952年的论文也越来越多地被生物学家引用。该模型已更新为包括基因产物,现在似乎能够解释生物学模式的产生,尽管模型和生物现实之间仍然存在差异。然后,我指出EricDavidson基于基因调控网络分析及其数学建模的早期胚胎发生成功理论,不仅能够为控制发育细胞命运规范的基因调控事件提供机制和因果解释,而且,与反应扩散模型不同,还讨论了进化和生物长期发育和物种稳定性的影响。最后对基因调控网络模型的进一步发展进行了展望。