I don't know.There is medical perspective which focuses on deleterious mutations causing disease. This is a black-and-white perspective which sees mutations as

I don't know.There is medical perspective which focuses on deleterious mutations causing disease. This is a black-and-white perspective which sees mutations as either wholly bad or entirely unimportant. A genome without any deleterious mutations is a correct genome. But what happens if you step back from black-and-white thinking and ask about mutations with ambiguous effects. Which is the mutation and which is the correct genome? It becomes unclear. An alternative perspective asks: how well separated are the local minima in fitness space? Perhaps the typical separation is as large as the gaps between species. Then each species has only its own local minimum, which defines its correct genome. Or perhaps fitness space is littered with local minima, such that a single species has genetically healthy individuals in several different minima plus other individuals, perhaps not quite so healthy, nearby.