Life Unfolding: How the human body creates itself

Life Unfolding: How the human body creates itself

Jamie A. Davies

Language: English

Pages: 641

ISBN: B01FIXERFC

Format: PDF / Kindle (mobi) / ePub


Where did I come from? Why do I have two arms but just one head? How is my left leg the same size as my right one? Why are the fingerprints of identical twins not identical? How did my brain learn to learn? Why must I die?

Questions like these remain biology's deepest and most ancient challenges. They force us to confront a fundamental biological problem: how can something as large and complex as a human body organize itself from the simplicity of a fertilized egg? A convergence of ideas from embryology, genetics, physics, networks, and control theory has begun to provide real answers. Based on the central principle of 'adaptive self-organization', it explains how the interactions of many cells, and of the tiny
molecular machines that run them, can organize tissue structures vastly larger than themselves, correcting errors as they go along and creating new layers of complexity where there were none before.

Life Unfolding tells the story of human development from egg to adult, from this perspective, showing how our whole understanding of how we come to be has been transformed in recent years. Highlighting how embryological knowledge is being used to understand why bodies age and fail, Jamie A. Davies explores the profound and fascinating impacts of our newfound knowledge.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

kidney cancer, Wilms tumour, hence the name. WT1 is also involved in sex determination. TECHNICAL REFERENCES Chapter 2: From One Cell to Many 1. Inoué S, Salmon ED. Force generation by microtubule assembly/disassembly in mitosis and related movements. Mol Biol Cell. 1995;6:1619–40. 2. Schatten H. The mammalian centrosome and its functional significance. Histochem Cell Biol. 2008;192:667–86. 3. Reinsch S, Gönczy P. Mechanisms of nuclear positioning. J Cell Sci. 1998;111:2283–95.

hotspots of turbulence results in a system of tubes in which flow is gentle, forces are low, and little of the heart’s power is wasted by throwing energy away in turbulence. It is, once again, adaptive and automatic. The adaptability of blood vessel development is very important to our ability to maintain and repair ourselves, as is explained in Chapter 18, but it comes with a price. Tumours, like ordinary tissues, consist of cells that are healthiest when oxygen is plentiful. When cells in the

hotspots of turbulence results in a system of tubes in which flow is gentle, forces are low, and little of the heart’s power is wasted by throwing energy away in turbulence. It is, once again, adaptive and automatic. The adaptability of blood vessel development is very important to our ability to maintain and repair ourselves, as is explained in Chapter 18, but it comes with a price. Tumours, like ordinary tissues, consist of cells that are healthiest when oxygen is plentiful. When cells in the

the molecules are different (they have to be, to avoid confusion) but the action is the same. From this point, the organ, which consists only of this little tube surrounded by mesenchyme, can be removed from the embryo and placed alone in a Petri dish and it will continue to develop normally.† It is therefore already essentially autonomous and able to organize itself from this stage. Both the mesenchyme and the ureteric bud have to be present, though—neither can be cultured alone unless an

every embryo. FIGURE 57 The ‘maleness’ cascade, that activates the Sox9-FGF signalling latch. One of the first actions of the SOX9 protein is to ensure its continued production. This is important, because the embryo has to make a clear and irrevocable decision about which sex to be if it is to avoid making a body that is neither fully male nor fully female. SOX9 expression activates a signalling pathway, based on the signalling by FGF proteins,* that in turn drives the production of more

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