Bioinformatics for reading the past

If scientists are able to extract a gene or a protein from a fossil, it is even better! But extremely rare. Indeed, the organic parts of an animal in the process of fossilization can survive thousands of years – and no more – before being replaced by minerals.

A survivor

In 2007, American scientists were understandably stunned when they discovered an almost intact protein in the fossilized bones of a 68 million year old Tyrannosaurus! The protein had been buried deep down in a bone and miraculously protected from mineralization. But which one was it?

Which protein?

Having extracted the protein from bone, the paleontologists assumed that it was most probably collagen – one of the major components of bone. The protein sequence was determined in the laboratory and then compared with millions of others stored in databanks, using bioinformatics tools. The scientists were thus able to prove their initial hypothesis: the Tyrannosaurus protein was indeed collagen.

Who are the descendants of Tyrannosaurus?

Finding collagen in a bone – even from Tyrannosaurus – is not surprising. However, scientists now have 68 million year old collagen that they can compare with the collagen of thousands of other living species. Why would they do this? To find out how Tyrannosaurus – and dinosaurs as a whole – are related to other species.

Chickens!

Tyrannosaurus collagen is very similar to a chicken’s! So do birds and Tyrannosaurus belong to the same family? In truth, scientists had already made that assumption following anatomical comparisons. Today, they have genetic confirmation of their hypothesis.