Dramatic DNA Research

 

The scientist involved

The scientist involved

Image via – http://en.wikipedia.org/wiki/File:Plos_paabo.jpg

Since 2003, when the ground-breaking Max Planck Institute of Evolutionary Biology opened in Leipzig, lead researcher there – the Swedish scientist Svant Paabo – head of evolutionary genetics, has transformed the study of human origins. With a passion for absolute laboratory sterility, and an unwavering attention to the smallest detail, this extraordinary biologist counts, among his achievements, the sequencing of an entire Neanderthal genome, which demonstrated just how close the links are between this extinct human species and modern man, as well as having discovered, from only a finger bone found in a Siberian cave, that there was a hitherto unknown human species, called the Denisovans.

Paabo himself is astounded that the research has made it possible to resurrect genomes from DNA that is several hundred thousand years old, because the fact is that such research is among the most difficult and demanding for science. One must bear in mind that nature designed organisms to retain DNA whilst alive, as it serves a vital purpose, but once death has occurred, the DAN begins to decay, the long fragments becoming ever shorter as time passes. That is why, in the case of really ancient samples, the piecing together – properly, of such impossibly tiny fragments represents such a huge challenge, yet Paabo and his team achieved miraculous results.

 

A full account of this incredible journey of discovery is given in soon-to-be-released Neanderthal Man: In Search of Lost Genomes, by Basic books, in which the 58-year-old geneticist reveals that it was his Nobel Prize winning biochemist father who inspired his son to pursue a similar career path. To that end, Paabo studied medicine and later biochemistry at Uppsala University, and at that time developed a fascination for studying DNA and how it relates to diseases. He specifically wanted to study ancient DNA, and secretly began in 1981.

Over time, the enterprising Paaabo tried extracting DNA from Egyptian mummies, succeeding in isolating a 2400 year-old short segment from an infant boy mummy, and published his findings in Nature, in 1985, stirring up a lot of interest. At the beginning of the 1990’s, he was at Munich university, and began hi so-called Neanderthal DNA project. To be fair, it took several years of serious cajoling, on his part, to obtain just one sample of bone from the original Neander Valley skeleton. His brainwave was that he might have more success studying mitochondrial DNA, and so it proved, for to huge acclaim he successfully isolated DNA sequences very different from modern human beings. This led to his being invited to join them at Max Planck.

He was one of many top men in the fields of biology, evolution and paleontology who together strove to establish a world-class anthropology centre.  It was to be 2006 before Paabo would announce his intention to sequence a full Neanderthal genome made of nuclear DNA. this was made possible by the wildly expensive new-generation sequencing machines, and in 2009, his published results astounded the entire scientific community, in that that the comparison of that Neanderthal genome to modern humans showed that the modern people had an average of two per cent Neanderthal DNA, meaning that interbreeding must have far more common than had ever before been believed.

As much of a triumph as this work had been, Paabo went one better in 2010, when revealing to the astonished scientific world  that, from only a fingertip, unearthed in Siberia – in what had been believed t be the dwelling of Denisovans – the had sequenced DAN that revealed these humanoids to be not Neanderthal, but in fact a hitherto unknown human species. These discoveries are indeed amazing, but just how much further back in time Paabo can successfully go remains to seen.  One day, with luck, we will finally get to see just how a million year-old human looked.

“Obviously there is a limit to how far back we can go in time with this approach,” he says. “DNA fragmentation is a real issue. Nevertheless, I think one day that we will be able to sequence DNA that is 500,000 years old – and possibly a million years. And who knows what that will throw up.”


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