Board Thread:Naruto Discussions/@comment-3279282-20140413164418/@comment-28861328-20140413173122

Omnibender wrote: Mu sensed that the Fourth Kazekage's chakra was similar to Gaara's. Kakuzu can get other's chakra affinities by transplanting their hearts, which have always been heavily associated with chakra production. The quality of chakra has some biological basis. The fact that Yamato can use Wood Release on account of Orochimaru's experiments is proof of it.

This is exactly what I was thinking.