>"The "bottoms up" approach you mention seems like it could be really powerful and definitely complementary to whats being done now. I have however seen a lot o

>"The "bottoms up" approach you mention seems like it could be really powerful and definitely complementary to whats being done now. I have however seen a lot of approaches "sort of" like that not work that well." Such as? I mean that is just the (correct) discrete version of Armitage-Doll, their continuous approximation only works for very low mutation rates and/or short time frames. What did you see that didn't work?