[MEGoody]

40 million evolutionary events

I'm always being told 'just look how close chimp DNA is to human DNA'. Okay, so tell me, how do we know it was '40 million evolutionary events' and not some other number?

[MRMEAN]

They counted. See Article Nature 437, 69-87 (1 September 2005) | doi: 10.1038/nature04072
Initial sequence of the chimpanzee genome and comparison with the human genome
The Chimpanzee Sequencing and Analysis Consortium25 which is one of the article's links.