1% dna different. The point he makes is that 1% dna difference produces a vast difference (by our measures) in intelligence, so that any Alien life (which we'd

1% dna different. The point he makes is that 1% dna difference produces a vast difference (by our measures) in intelligence, so that any Alien life (which we'd expect to be vastly different in dna) is likely to be either vastly superior or inferior to us in intelligence, meaning either way someone is going to look awfully stupid.