Old protein distinguishes bone fragments of Neanderthals
Bone remains that are thousands of years old are often too fragmented to be identified. PhD candidate Frido Welker is the first person to be able to distinguish human bones from one another on the basis of old proteins. PhD defence 18 May.
When did the Neanderthals die out, and when did modern man arrive in Europe? Archaeologists try to answer these kinds of questions by studying the bone remains of these hominids. The problem they have is that most bone remains are too fragmented: it's impossile to recognise them with the naked eye and the DNA has often already disappeared. As a result, there is uncertainty about when the last Neanderthals and the first modern men were present in Europe.
But protein variation is not the only source of information about the history of a piece of bone. With a protein like collagen type I, that is present in high concentrations in bones, it is possible to distinguish a bison from a hominid. This is because the protein itself varies between species. This technique is known as zooarchaeology by means of mass spectrometry (ZooMS). Frido Welker uses ZooMS to determine the origin of hundreds of bones, in the hope of identifying bones of hominids that have not yet been discovered. 'Unfortunately this technique is not able to make the distinction between hominids, such as between a Neanderthal and a modern human,' he explains.
Collagen type X
Other old proteins in these bone fragments are able to do this, Welker discovered in the course of his PhD research in partnership with the Max Planck Institute for Evolutionary Anthropology in Germany. ‘Even bone fragments that are fifty thousand years old can still contain dozens of different bone fragments. A few of these, such as the collagen type X protein, contain enough variation to distinguish between hominids.' Welker uses a highly advanced mass spectrometry technique in his research: LC-MS/MS.
Using this technique, Welker has demonstrated that human bone remains from the Grotte du Renne in France are from Neanderthals and not from modern man. The cave at Renne is an important archaeological site of the Châtelperronian period: an ancient industry dating from between 43,000 - 38,000 before Christ. Welker: ‘We now have the first molecular-biological evidence that the Châtelperronian industry was made by Neanderthals.'
Schat aan informatie
Welker wil de oude eiwitten ook gebruiken om fysiologische eigenschappen uit de botten te achterhalen, zoals of de mensachtige stress of ziektes had. ‘Het is heel bijzonder dat we uit botresten die eerst als waardeloos werden gezien, nu een schat aan informatie kunnen halen’, zegt Welker. ‘Met deze techniek kunnen we nu ook de ontstaansgeschiedenis onderzoeken van menselijke fossielen waarin het DNA niet meer aanwezig is. Daarnaast willen we zowel ZooMS als LC-MS/MS op een grotere schaal toepassen bij archeologische sites in Europa, om de menselijke evolutie beter in kaart te brengen.’