Naruto Chapter 545

[rockmanj]

So how come Tsunade can't use Mokuton? Is she a dope?

Maybe it is something not commonly inherited; kind of like how some Uchihas did not have the sharingan. I think Tsunade has a similar mark to her grandmother, though (the Yin seal). I would think she would have a long life too, except for the fact that she used that Yin seal release on a lot of people in Konoha during the Pain invasion.

[SilentSnake]

Maybe it is something not commonly inherited; kind of like how some Uchihas did not have the sharingan. I think Tsunade has a similar mark to her grandmother, though (the Yin seal). I would think she would have a long life too, except for the fact that she used that Yin seal release on a lot of people in Konoha during the Pain invasion.

AFAIK every single instance of sharingan evolving/activating at all was connected with emotional events like protecting someone dear/killing best friend/killing brother etc. so I presume all uchihas had the ability to awaken the sharingan, but not all of them went through events traumatical enough to awaken it.

Who's to say Mokuton is passed genetically? The Second didn't have it either and he was his brother.

Well, it sure is a DNA thing:

http://www.mangareader.net/naruto/545/3

[Archangel]

The fact that his abilities are possible due to his genetics doesn't mean it's something passed from father to son. For all we know it's a Down Syndrome kind of deal, only instead of being retarded he ended up with super immortal powers.