Who do you think we are?

In the last decade, the fast-growing field of human ancient DNA – genetic material extracted from skeletons excavated from archaeological sites – has revealed much about the demographic history of Europe (and the world). The genomes of present-day Europeans broadly comprise ancestries from three major groups: 1) indigenous hunter-gatherers; 2) Near Eastern early farmers; 3) Steppe pastoralists. However, the local genetic history of any given area is always more complex. An example of this is modern-day Ukraine, which has been in the path of several migrating groups.

On an evolutionary timescale, milk and dairy foods are recent additions to adult human diets that have had profound impacts on our culture and biology. For over 10,000 years, some human populations have incorporated dairy into their diets, adapting culturally with fermentation and cheesemaking. Some populations have also adapted genetically with lactase persistence, the continued expression of the gut enzyme lactase into adulthood. We will look at the archaeological evidence for dairy consumption together with the genetics and evolutionary history of lactase persistence.

Back in the 11th Century, Christianity in England was very different to what it is now: love and charity were tempered by a healthy dose of authoritarianism and vengefulness. So when a Viking raider shows up at your local vicarage to snatch the communion silver, what do you do? Flay them alive of course, and nail their skin to the front door as a lesson to others. According to local mythologies, this happened repeatedly in rural England (Vikings never learn). A millennium later, I analysed the skin fragments still stuck under the 11th Century ironwork to find out the truth of these stories…

Events in human history (e.g., the formation of new empires, invasions, the development of trade routes, large-scale migrations) can cause previously separated groups of people to meet and mix together. If your ancestors experienced such a mixing event, your genome will be made up of a mosaic of chunks of DNA inherited from the mixing groups. Therefore, with new techniques and a large genetic dataset we can determine which groups mixed and when. The final step is to match the genetic signal with the (known or unknown) historical event…