Francis Crick was a polymath - a literate guy who crossed from the physical sciences to help solve one of the great mysteries of 20th century biology, the double-helix of DNA.   There are numerous others but science has become increasingly specialized and that is essentially, it is said, in a more complex world.

In "It's Sad But True That Most Discoveries In Biology Are Made By Physicists" - Freeman Dyson it was discussed that more and more complex problems would be ill-suited for just one field, biology being an example, and polymaths are becoming more prominent again. 

At Discover blogs, writer Ed Yong details the story of Erez Lieberman Aiden, a polymath he incorrectly calls a Renaissance Man.  I say incorrectly because I am a renaissance man - along with programming this site and writing about science, I also was an accomplished artist, a competent musician and a warrior in both the literal military and the martial arts sense.   

Regardless of the subtleties of language - Yong can call him a renaissance man if he chooses but I prefer more precise prose (from better writers than me anyway, and Yong has writing prizes in his bio, so he must be better than me) - he does a terrific piece on what is without doubt a cool guy doing a lot of cool stuff.

The Renaissance man: how to become a scientist over and over again - Discover blogs