Neanderthals lactose Intolerant.

First draft of the neanderthal genome was announced.  Very little evidence for interbreeding with humans, and the following tidbit.

First draft of Neanderthal genome is unveiled - life - 12 February 2009 - New Scientist

The new sequences suggest that the Vindija Neanderthal lacked the ability to digest milk sugar in adulthood - a trait that became common among northern Europeans and Africans only in the last 10,000 years.