Sorry for the double post (not really)...
So, it turns out that the ninja's obsession with bloodlines is actually based on something real. Turns out people get chakra from their parents. And given that SSP's mom got her chakra by eating a fruit of the Juubi (Juubi's unborn kid?) it looks like the Huuyga might be right to worry about transplanting byakugan. Also, Yamato got Harashima's chakra nature from his DNA, so chakra transplantation is still possible.
The really interesting part is that humans did not originally have chakra. But as of the time of the series, they can't live without it. And this doesn't have anything to do with them using chakra for jutsu. We've had people(almost) die from running out of chakra so it's not humans can just "give back" the chakra they stole. What's also interesting is that people are contently regenerating chakra as well as have the capability to increase the amount of chakra they produce. So at some point between the first Jubbi and the start of the series, chakra stopped being something people stole, and started being there's.
Also, humans aren't the only ones who have chakra now. There's all the summoning animals that have chakra and can do jutsu. And it's a different type of jutsu then humans do, but it can effect the Juubi while human's jutsu can't. Have to wonder whether the summoning animals has chakra before people did, or if they got it afterwards. I'm betting on afterwards.
What I really have to appreciate is that the SSP split the Juubi in to 9 intelligent animals instead of 9 plants. Plants don't have brains (even if the Juubi was sentient, it was a plant), but animals do, so they're closer to humans. What's interesting is why he split the Juubi up and that while the bijuu are distructive, they're more like forces of nature, then actively trying to get back the chakra that was stolen from the Juubi. Now that's all that work's been undone.
Also interesting is that it's the Uchiha who still have the history of what went down with the Juubi, but the Senju don't. I'm thinking the Uchiha have it because they can get the right eyes to see what was recorded.
Okay, it's really freaky that Harashima has the Mukuton jutsu now. It looks like that's the chakra nature of the Juubi. No wonder Orochimaru wanted it so badly (did he know about this already?). Speaking of Orochimaru, he'd probably love this, if not for the fact that it's leading to a world-wide genjutsu.
It's more apparent then ever now that Madara and Obito have two very different things they want to accomplish with the Juubi. Oh, and Sasuke doesn't even want the genjutsu to happen. Three-way Uchiha fight anyone? What's also crazy is that being the junchuriki of the biggest of the the bijuu, and therefore having more chakra then anyone else is finally a major weakness for Naruto; the Juubi is going to be gunning for him out of everyone else.
Also, I have my suspicions that Salmehada is somehow related to the original Juubi. It's a sentient sword that eats chakra and likes people which large chakra reserves. Only instead of eating their chakra, it gives them the chakra it's eaten. Broken off piece of the original Juubi that formed an attachment to humans once the original Juubi was sealed maybe?
It's also worth mentioning that the whole "history of how we got chakra" conversation takes place between Madara and Harashima, so they're the only two people who know all this stuff.
Well, at least Naruto isn't on break next week, that would be torture.