I remember reading the chapters on scents and vision and thinking exactly the same thing. I think people get this impression because Shubin stresses the percentage of our genome that is devoted to smelling. He mentions it on at least two pages; 144 and 146. That's more than a 1/5 of the chapter devoted to discussing it. I didn't find anything like that for the eye - which should take up way more than the nose. Shouldn't it?
I tried to find something online about this but I couldn't.
