From where came the Slavs?

In my previous post I contended that biology is an important causal factor to keep in mind when we model the behavioral ecology (a.k.a., history) of H. sapiens. A separate, but complementary, tack is to use genetic data to supplement what we know from other historical sciences (history, archeology, economic history, etc.) to obtain a better picture of the dynamics which were operative in the past and the sequence of events which result in the shape of the present. The Etruscan genetics story is a perfect case study; genetic data pretty much sealed the deal in allowing us to distinguish between equally plausible hypotheses (or, more honestly, it radically altered the weights of plausibility). Another historical demographic question that I've been mulling recently: how is it that the Slavic speaking peoples expanded to occupy their current range with the last 2,000 years? Did they migrate or expand through demic diffusion? ...