SovietFireExtinguisher;2884415; said:There is DNA evidence that in Humans those two extra chromosomes flipped over and fused. This is all readily on the Internet for you googling pleasure.
Where is your link? The DNA "evidence" you refer to is old and established before we knew how DNA binds. Large "flips" are inheritnly impossible since the negatively charged side of the helix needs to have enzymes placed on it in reverse order one at a time, because the "builder" is positively charged. Of course to get to the building point the cell would have had to pass all the spindel checks (that make sure the DNA is in the proper order and no cell damage has occured). This is pretty basic microbiology: http://en.wikipedia.org/wiki/Cell_cycle

