We have 23 pairs of chromosomes. The ape primates have 24 pairs. Our chromosome 2 is a fused pair of chromosomes when compared to chimp amd gorilla, indentified by centromeres and telemeres in the wrong places. Perhaps this change is why we are so different from our primate cousins; different in kind, not degree:-http://blogs.discovermagazine.com/loom/2012/07/19/the-mystery-of-the-missing-chromosome-with-a-special-guest-appearance-from-facebook-creationists/-We can only guess as to how important this is at defining the differences between apes and us.