Here he is on his blog:
All heritable differences between species, in fact, must reside in the DNA; we know of no cases in which they don’t. Where else could they be?Heritable differences between species can also reside in culture or the environment. The fact that modern humans have rocket-ships and Neanderthals did not is due to cultural variation - not genetic variation. It just isn't true that heritable differences "must reside in DNA". The idea that "we know of no cases in which they don’t" is just bunk. About 20-40% of variation in modern humans is due to cultural inheritance. That's not as much variation as DNA is responsible for - but it is a non-trivial amount.
Heredity can also reside in the environment. For instance, most marsupials over the last million years have inherited their position on the Australian continent from their parents - along with their DNA. Position is inherited too.
This is similar to the last time - where we had:
Geneticists now know the genetic basis of dozens of adaptive traits that differ between populations and species. All of them reside in the DNA. If non-genetic adaptive change was common, we would have found it.Coyne has a long history of misunderstanding cultural evolution. One wonders when the penny is finally going to drop with him.