Excerpt:
“If you have a big bag full of marbles of different colors, and you lose most of them, then you will probably end up with a small bag that won’t have all the colors that you had in the big bag,” he says.
Similarly, if the size of the human population was severely reduced some time in the past, or several times, the “colors” that make up our genetic variability will also be reduced.
If that is indeed what happened, then we should be more like each other, genetically speaking, than the chimps and gorillas of Africa. And that’s just what the research shows.
“We all have this view in our minds that we [humans] started precariously as sort of an ape-like creature” and our numbers grew continuously, adds Wood. “We’re so used to the population increasing inexorably over the past few hundred years that we think it has always been like that.”
But if it had, Gagneux notes, our genetic variability should be at least as great as that of apes.
Had to. Somehow "we" were responsible for the extinction of the dinosaurs too.