mummies—with the plastic bags containing the piece of the Neanderthal type specimen and asked him to apply our latest and best methods to it.
Figure 5.3. The right upper arm bone of the Neanderthal type specimen with the sample removed by Ralf Schmitz in 1996. Photo: R. W. Schmitz LVR-LandesMuseum Bonn.
Chapter 6 A Croatian Connection
________________________________
During the weeks and months after our publication of the Neanderthal mtDNA sequence, I reflected on what had led up to it. I had come a long way from my first attempts sixteen years earlier to extract DNA from a piece of dried calf’s liver from the supermarket. Now, for the first time, we had used ancient DNA to say something new and profound about human history. We had shown that the archetypical Neanderthal carried mitochondrial DNA very different from the mtDNA in people today, and that he or his relatives had not, before they became extinct, contributed their mtDNA to modern people. The achievement had required years of painstaking work to develop techniques to reliably determine DNA sequences from individuals long dead. Now that I had these techniques at my disposal, and a group of dedicated people able and willing to try new things, the biggest question was: Where should we go from here?
One task seemed of immediate importance: to determine mitochondrial DNA sequences from other Neanderthals. As long as we had studied only one individual, it remained possible that other Neanderthals carried mitochondrial genomes very different from the one from Neander Valley, perhaps even carrying mitochondrial genomes that were like those of present-day humans. Mitochondrial DNA sequences from additional Neanderthals would also reveal something about the genetic history of the Neanderthals themselves. Present-day humans, for example, have relatively little genetic mtDNA variation. If Neanderthals did, too, this would suggest that they had originated and expanded from a small population. If, on the other hand, they had as much mtDNA variation as any of the great apes have, this would suggest that over their history their numbers had never been very low. They would not have had such a dramatic history with ups and downs in population size as modern humans have. Matthias Krings, eager to follow up on his success with the iconic type specimen from Neander Valley, was keen to examine other Neanderthal specimens.
The major problem was getting access to fossils sufficiently well preserved for us to do work.
I thought a great deal about why we had been successful with the Neander Valley type specimen and came to realize that the fact that it had come from a limestone cave might be significant. Tomas Lindahl had taught me that acid conditions cause DNA strands to disintegrate, which was why the Bronze Age people found in acid bogs in northern Europe had never yielded any DNA. But when water passes over limestone, it becomes slightly alkaline. So I decided we should concentrate on Neanderthal remains unearthed in limestone caves.
Unfortunately, I had never paid much attention to the geological features of Europe in school. But I remembered the first anthropological conference I had ever attended, in Zagreb, in what was then Yugoslavia, in 1986. During the conference, we were taken on excursions to Krapina and Vindija, two sites where large amounts of Neanderthal bones had been found in caves. I made a quick search in the literature and confirmed that both Krapina and Vindija were limestone caves, which was promising. Promising as well was the presence of large numbers of animal bones, particularly of cave bears, in the caves. Cave bears, which were a large plant-eating species, became extinct shortly after 30,000 years ago, just like the Neanderthals. Their bones often abound in caves, often in circumstances suggesting that they died during hibernation. I was happy about the presence of cave-bear bones because they could possibly serve as a convenient tool
Figure 5.3. The right upper arm bone of the Neanderthal type specimen with the sample removed by Ralf Schmitz in 1996. Photo: R. W. Schmitz LVR-LandesMuseum Bonn.
Chapter 6 A Croatian Connection
________________________________
During the weeks and months after our publication of the Neanderthal mtDNA sequence, I reflected on what had led up to it. I had come a long way from my first attempts sixteen years earlier to extract DNA from a piece of dried calf’s liver from the supermarket. Now, for the first time, we had used ancient DNA to say something new and profound about human history. We had shown that the archetypical Neanderthal carried mitochondrial DNA very different from the mtDNA in people today, and that he or his relatives had not, before they became extinct, contributed their mtDNA to modern people. The achievement had required years of painstaking work to develop techniques to reliably determine DNA sequences from individuals long dead. Now that I had these techniques at my disposal, and a group of dedicated people able and willing to try new things, the biggest question was: Where should we go from here?
One task seemed of immediate importance: to determine mitochondrial DNA sequences from other Neanderthals. As long as we had studied only one individual, it remained possible that other Neanderthals carried mitochondrial genomes very different from the one from Neander Valley, perhaps even carrying mitochondrial genomes that were like those of present-day humans. Mitochondrial DNA sequences from additional Neanderthals would also reveal something about the genetic history of the Neanderthals themselves. Present-day humans, for example, have relatively little genetic mtDNA variation. If Neanderthals did, too, this would suggest that they had originated and expanded from a small population. If, on the other hand, they had as much mtDNA variation as any of the great apes have, this would suggest that over their history their numbers had never been very low. They would not have had such a dramatic history with ups and downs in population size as modern humans have. Matthias Krings, eager to follow up on his success with the iconic type specimen from Neander Valley, was keen to examine other Neanderthal specimens.
The major problem was getting access to fossils sufficiently well preserved for us to do work.
I thought a great deal about why we had been successful with the Neander Valley type specimen and came to realize that the fact that it had come from a limestone cave might be significant. Tomas Lindahl had taught me that acid conditions cause DNA strands to disintegrate, which was why the Bronze Age people found in acid bogs in northern Europe had never yielded any DNA. But when water passes over limestone, it becomes slightly alkaline. So I decided we should concentrate on Neanderthal remains unearthed in limestone caves.
Unfortunately, I had never paid much attention to the geological features of Europe in school. But I remembered the first anthropological conference I had ever attended, in Zagreb, in what was then Yugoslavia, in 1986. During the conference, we were taken on excursions to Krapina and Vindija, two sites where large amounts of Neanderthal bones had been found in caves. I made a quick search in the literature and confirmed that both Krapina and Vindija were limestone caves, which was promising. Promising as well was the presence of large numbers of animal bones, particularly of cave bears, in the caves. Cave bears, which were a large plant-eating species, became extinct shortly after 30,000 years ago, just like the Neanderthals. Their bones often abound in caves, often in circumstances suggesting that they died during hibernation. I was happy about the presence of cave-bear bones because they could possibly serve as a convenient tool
Similar Books
