Paul Saladino· MD
so we know well we don't know this is all you know there's a bits of data and and we have to gather more data because sometimes science corrects itself but I guess it was a little over a year ago now pair of papers were published that argued that a huge part of our brain expansion is brought about by this notch 2nl gene and this is a gene so one of the ways that evolution works quite commonly is that on and the duplication event it accidentally creates a double copy of a gene and that's really kind of a fortuitous circumstance because the second copy is no longer needed to do what the first copy did if you start adjusting the first copy it won't do its job anymore but if you've got a spare copy you can kind of do anything you want with it because the first copy still doing the proper job that needs to be done so I think it was a around 12 million years ago in our line that first that duplication event seems to have taken place and it was then turned off and it's sad in our line that's the sort of two gorillas at that time gorillas and chimps and us all the same animal it sat on that line dormant for about nine million years and then it turned itself on and duplicated itself and what this gene does is it maintains neurons and stem cells for longer and so in other words they duplicate more before they actually become brain cells