Actually, Big Boss WAS fifty when he was cloned, but Kojima himself said he changed the timeline a little in order to make Snake Eater work better.

Ocelot and EVA (I refuse to call her Tatyana on the grounds that, she was lying when she said it) were raised by The Philosophers, note how EVA calls herself a "Child of the Philosophers", The Patriots were an offshoot from The Philosophers.

Anyway, this pretty much covers the plot :
http://img.penny-arcade.com/2001/20011130l.gif