How a geneticist came to do history
As he puts it in the subtitle of his memoir, “Neanderthal Man,” Svante Paabo goes in search of lost genomes. Dr. Paabo, a 59-year-old Swede who leads his own laboratory at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, was the first to extract and sequence the genomes of the ancient humans called Neanderthals and Denisovans, and to compare them with those of modern humans. Genes, and the stories they tell, are texts he reads.
We recently spoke for three hours in Washington, and later on the telephone. Here is an edited and condensed version of our conversation....
HOW DID YOU COME TO INVENT AN ENTIRELY NEW RESEARCH AREA, THE GENETICS OF ANCIENT HUMANS?
In the late 1970s, while I was doing my medical studies [at Uppsala University in Sweden], these new techniques for studying DNA were introduced — cloning, sequencing. I was amazed by them and learned how to do them.
And that brought me to thinking again about Egyptian antiquities. I knew that there are hundreds of mummies stored in museums across Europe. Mummies, after all, are the dried-out bodies of dead people or animals. I wondered if in some, their DNA might still be preserved. If it was present, we could study it just as we study the DNA of people alive today.
My thought was, “If we could do this, we can answer many questions in history that we cannot otherwise answer.”
SUCH AS?
Are the people who built the pyramids the direct ancestors of the people who live in Egypt today? Or: When the Neanderthals encountered modern humans, did they mix?
But to do this, one needed to obtain DNA that might be preserved in those ancient human remains. In the 1970s, many people thought that DNA was so sensitive a molecule that it probably degraded within hours of death. I thought I should test that idea. So I bought a piece of calf’s liver and dried it in an oven. The DNA survived!
Encouraged, I went on to test for DNA in some Egyptian mummies kept in our small museum in Uppsala. However, I couldn’t find any DNA in a single one. Eventually, my Egyptology professor, who had some contacts in what was then East Germany, arranged for me to go to the Bode Museum to collect samples from their large collection of mummies.
Back in Uppsala, I studied the samples from the Bode mummies under a microscope, always searching for the remains of a cell nucleus. This is a part of the cell where the genome is located. After a few weeks, I detected a cell nucleus that appeared to contain preserved DNA. This was so encouraging....