The genetics of emergent phenotypes
Source Why are some brain disorders so common? Schizophrenia, autism and epilepsy each affect about 1% of the world’s population, over their lifetimes. Why are the specific phenotypes associated with those conditions so frequent? More generally, why do particular phenotypes exist at all? What constrains or determines the types of phenotypes we observe, out of all the variations we could conceive of? Why does a system like the brain fail in particular ways when the genetic program is messed with? Here, I consider how the difference between “concrete” and “emergent” properties of the brain may provide an explanation, or at least a useful conceptual framework There is now compelling evidence that disorders like epilepsy, schizophrenia and autism can be caused by mutations in any of a very large number of different genes (sometimes singly, sometimes in combinations). This is fundamentally changing the way we think about these disorders. It is no longer tenable...