The secret is in the hair

Posted on 27 September 2007

Post Doc Thomas Gilbert from University of Copenhagen has developed a new and more precise method for analysing DNA in collaboration with international colleagues. The method is based on analysis of hair shafts and can be used for many things e.g. uncovering the life of mammoths during the ice-age or human migration studies across continents. Or even to analyse hair from a crime-scene. Thomas Gilbert is part of Professor Eske Willerslev’s Evolutionary Biology research-team. The new DNA-method is published in Science.

DNA in hair

Historically, hair has had a magical and almost cultic importance in human history and was, for instance, believed to be a source of power.

Nowadays, hair is also the source of answers to a number of questions. The new DNA-method will give us more precise information about why the mammoth died out, or what the ingredients are in the cocktail of human races that are mixed in Europe and elsewhere. And in the future, it may be an improved tool for the police and in forensics to solve crimes.

“So far you would have to drill in old bones if you wanted to compare the genetic imprint of mammoths to that of elephants, or if you wanted to see how they coped during the ice-age before they died out. Usually, the problem is that the remaining DNA samples have been scarce, and that they have been “polluted” by bacteria. But DNA from hair is very clean because it has been encapsulated in keratin, a kind of plastic membrane that protects the hair and the DNA. Think about all the extinct furred animals that are displayed on museums around the world. There is a lot of work waiting for us” says Thomas Gilbert.

The new method

The new method is based on whole-genome shotgun sequencing of mitochondria. A mitochondrion is a kind of power plant in the cell, and it is very suitable for use in comparable DNA-studies of both mammals and humans.

Professor Eske Willerslev, who is an expert in DNA-traces in sediments and organisms and who recently found the worlds oldest living bacteria, is enthusiastic about the new method.

“It is not only interesting in relation to the past, but also to the present in e.g. forensics. But some development is needed yet for the method to be 100 per cent usable in that context. As it is, it takes a certain amount of hair to reach a conclusion. And you don’t always find that amount of hair in a crime-scene. But it is only a question of time and refinement. A further advantage is that the method can be combined with a very fast modern sequencing-machine and therefore give us answers overnight, whereas now we often have to wait for a long time to get the result of a DNA-test” says Eske Willerslev.

Thomas Gilbert has worked together with colleagues from a number of universities and research institutions in e.g. USA Russia, Belgium, France and Sweden on developing the method.