The great development in the methodology of archaeology in the past 15 or 20 years I think has been the application of DNA studies, and not so much ancient DNA, not so much taking DNA from human skeletons where it's quite difficult to get enough to give you a good signal, but by comparing the DNA from blood samples or saliva samples from living populations, you can compare the mitochondrial DNA which is what passes on in the female line or the Y chromosome DNA which is what passes in the male line and these change remarkably slowly by random mutations and it was realised by the molecular geneticists back in the '80s, that if you do this, you can see that our entire species, all living humans seem to be descended from an original population, and it became clear by looking at the distributions, that this population must have been in Africa. And this was initially controversial but I think has been very strongly confirmed subsequently and so that gives you the very strong conclusion that there must have been an out of Africa dispersal of human kind and it turns out that it was relatively recently, something like 60,000 years ago, and that has been, I think, enormously influential on archaeological thinking because until that time, it had been thought that the earlier fossil hominids, Homo erectus, Homo ergaster, who did leave Africa and had, one finds their archaeology, their hand axes in Britain or comparable things in, in Asia. The thinking was that maybe Homo sapiens, our own species might have evolved separately in different parts of the world with a sort of multi-lineal evolution, which was very strongly argued by some scholars in Australia and so on. Well, it looks as if the DNA studies rather knocks that on the head and so it's clear that DNA studies using mainly samples from living populations can, in favourable circumstances, give you real insights into population histories. And the origin of our history of Homo sapiens is a very strong case, where I think that's very persuasive and has to a very considerable extent reshaped our thinking about the transition to our own species, Homo sapiens, and therefore reshaped our thinking about the upper Palaeolithic, the lower and middle Palaeolithic being associated with those earlier hominids mainly, and that's had a great impact on our thinking. But also it must be relevant to later periods. If there were great migrations of people, well, then that ought to leave some trace in the record of the molecular genetics and might also be something one could learn about by studies of living populations. So that was something I was already getting interested in early on, but with the establishment of the McDonald Institute, it seemed possible to try and do something in that direction so we decided to appoint a fellow in molecular genetics, and we were very fortunate that Peter Forster applied and got the job and so for some years in the McDonald Institute, we had a laboratory where such studies were being undertaken, but also the presence of Peter Forster put us very much in touch with the thinking that was going on in different places in this country and in the United States. And the history of molecular genetics has been very exciting. The great sort of father figure who was interested in applying the genetics even before DNA analysis was very practical, that's Luca Cavalli-Sforza, he had already been talking about population histories using traditional genetic markers, blood groups and so on before the different DNA haplotypes were available and then the Y chromosome haplotypes, so he's been involved with that work also, but he'd already established a framework and then he had suggested that the genetic evidence from blood groups mainly indicated there was a significant movement of population at the beginning of the Neolithic. But that became less and less clear-cut as the data were examined and as the DNA evidence came forward, it's clear there were indications of movement of people but on a small scale with the origins of farming and most of the populations of Europe or the greater part owed their ancestry to pre-existing Palaeolithic hunter gatherer populations, so the situation became quite a complicated one and it's still one that's quite difficult to interpret, but that has been a very interesting area of study in the past 10 or 15 years and continues to be so and the great thing is great quantities of new data are becoming available as the analyses continue on samples from living populations and then there has been success also with Neanderthal DNA, so that fossil DNA is beginning to be relevant to the issue as well. So those have been some of the changes and that all relates back to the language problem and we've tried in the McDonald Institute to bring that into focus. We had a conference, a large conference on archaeogenetics, which was published in a volume of that title and it became clear really that the molecular genetic story was much more complicated than had initially been thought and in my own view it still seems likely that the spread of the Indo-European languages took place with the coming of farming but it wasn't a transfer or a complete, complete transfer of population. It was a spread of language with the spread of some farmers in small groups probably, who then became to a large extent genetically assimilated in Europe although to a large measure, the languages they brought with them or the language they brought with them did prevail except in a few enclaves like the Basque country where the Basque language seems to be a, a relic of the, the upper Palaeolithic. And then recently there have been developments in historical linguistics, nothing to do with the genetics as such except they have used mathematical methods formerly used to analyse genetic data, which have now been applied directly to linguistic data, phylogenetics methods and some of the work there, Gray and Atkinson in a paper in “Nature” a few years ago, using a linguistic evidence alone, came up with a conclusion that the Indo-European divergence from the original homeland must have taken place around 7,000 BC. So that is very strong support for the early theory, which would harmonise with the farming language dispersal model for Indo-European, but undoubtedly that's still a controversy that is raging. And it's one that's very difficult to settle, to reach a conclusion as to what language was being spoken in Europe some three or four thousand years before writing began anywhere, is obviously not easy and so I think the debate will continue for some time, but it certainly makes, throws open a number of possibilities and certainly one no longer has to write one's prehistory around some particular theory about the coming of the Celts or the coming of the Greeks so I think in some ways that is quite a step forward.