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Thank you for the opportunity to speak to this group. It is a particular pleasure to speak after Andrew Garrett. I'm going to talk about my work in ancient DNA, which is an extraordinary new enterprise that has become possible on a genome-wide scale since 2010 and has made it possible to take a direct look at past archaeological cultures. We can take skeletons like the one in Figure 1, extract DNA from them, effectively sequence their genome, and compare them to individuals from other ancient archaeological cultures and people today to determine how they are related.
For the first time, we can trace movements of people and ask whether transformations in material culture in the past correspond to movements of people or communication of ideas. It's a revolution in our ability to understand the past.
Figure 2 shows a tree reconstruction of the relationship of Indo-European languages. It is different in some of its features from some of the trees that Andrew showed, and I am not making any claim that this tree or another is correct in all its details.
The relationship among Indo-European languages was articulated at the end of the 18th century by Sir William Jones working in colonial India who noticed, as Andrew said, the connections between Sanskrit and the ancient European languages. Language provides compelling evidence of a strong cultural connection among these disparate places. It's a key observation because it indicates that there was cultural continuity across these regions.
Figure 3 shows how there has been an explosion in the amount of ancient DNA since 2010. There was a trickle of genomes between 2010 and 2013. Suddenly in 2014 and then again in 2015 there was a rapid increase in the number of individuals with genome-wide data. At the end of 2015 it was more than 300; it's now over 1,000. The sample size is rapidly increasing and this is allowing us to study how people from the past relate to each other and those of the present.
In 2009 a very important study was published in which mitochondrial DNA-in the energy factories of cells-was successfully extracted and sequenced from ancient Europeans. Bramanti and colleagues compared the mitochondrial DNA of hunter-gatherers and farmers in Europe who lived before...