"The last eight minutes of the "Prometheus" story evolve into a pretty good DNA of the 'Alien' one."
...in other words we'll see the same form of story telling evolve in Prometheus that we did in Alien. That could mean a few things, but basically he's talking about the similarities from a story arc, atmosphere, characters, settings etc., non of which suggest this will be a prequel any more than we'll see an alien in there.... what's so hard to figure out about that? .