Gene trees

It is well known that the genomes of humans and chimpanzees are very similar – over 95% similar in fact. The differences are in some ways more interesting than the similarities because they give clues as to how and when the ancestral line split apart. Then if you add into the mix the gorilla genome we can go even further back and predict when the human-chimp-gorilla line split.

The problem is that it’s not an exact science. There are a number of variables to factor in like different natural selection pressures, ancestral populations sizes, recombination, and gradual speciation etc, but a recent paper describes a new method of working it all out. They found that the divergence time of the human-chimpanzee line comes out consistently at around 4 million years ago and the human-chimp-gorilla split was around 6 million years ago.

The picture above shows just how complicated the flow of genetic information can get in what seems like a straight forward family tree.

The paper is here