Yes, the starting kernel of its learning this time was a collection of human games. This has caused the Policy Network (which says "given this board state, these moves are worth investigating in more detail") to be biased towards more human-like moves.

But they're already working on a new version of AlphaGo which isn't trained on any human data at all. It starts by making truly random moves and improves from there. This will require much more processing time and probably an order of magnitude more "self-play", but it will probably result in truly novel strategies that aren't part of the current human metagame.