ELi5: how can a single fertlized egg/cell produce a full body with so many different cell types? are we talking about extracting a compressed file or making factories which has different products to produce?
In: 22
Plenty of good answers, but I will try for a short and simple one:
1. Every cell contains full “blueprint” in its DNA, i.e. building instructions for entire body.
2. Cells can replicate, i.e. make copies of themselves (as long as they have access to nutrients).
3. Cells start out all same, but can specialize into types if conditions are right. Normal foetus development does create those conditions.
4. Cells can “communicate and coordinate” with each other, using chemicals (hormones) rather than nerves.
So cells replicate, specialize and arrange themselves according to the instructions in the DNA.
It still sounds like an very complex task to build a human body, and it is. Plenty of things can make it go wrong, e.g. drug use by mother, gaps in nutrition, or even foetus having a blood type that is mismatched with the mother.
If you want an analogy, it is a like having the last (or first) couple on Earth rebuild the society by having children, and having those children learn new professions. Except that everybody already has knowledge of every profession, and how the society should work. In fact, the Civilization game could be an even better analogy: you start with a single stone-age person, and end up with a modern civilization.
Latest Answers