Tuesday 12 March, 1–2pm, Dr Garrett Hellenthal, ‘Identifying and dating historical admixture events in humans using DNA’
4 March 2013
Gavin de Beer LT, Anatomy Building, UCL
We describe a new method that uses DNA to identify historical events that have shaped present-day populations. In particular, the approach exploits modern large-scale genetic collections to unearth times in the past where two or more genetically distinct groups interacted and exchanged DNA. The method dates precisely when such events occurred, characterizes the amount of DNA exchange, and describes the genetic composition of the (perhaps extinct) groups involved. We highlight the model’s advantages over currently available techniques in the field, including its improved parameter estimation and the additional information it contributes beyond any available methods. Our inference, based entirely on DNA, provides a powerful complement to anthropological resources, helping to resolve existing archaeological controversies, determine precisely how much DNA exchange accompanied known historical periods, and discover previously unknown events. We describe an application to data collected from 95 world-wide geographic regions, in which we characterize over 100 DNA exchange events occurring in the past 3000 years.