> Some very small genes have very large visible expression Let me change your italics: Some very small genes have very large visible expression So small part

> Some very small genes have very large visible expression Let me change your italics: Some very small genes have very large visible expression So small parts of the DNA code for changes that we can visually appreciate. This doesn't mean that the rest of the DNA contains no variations, but just that we cannot see them. But it would be wrong to assume that the only parts that are actually different are those which encode for visible characteristics.