Fellow: Anuradha Jagadeesan
Supervision: Dr. Agnar Helgasson
Host Institution: University of Iceland and deCODE Genetics, Reykjavik, Iceland
Duration: 3 years – starting from 1 June 2012
This project focuses on a highly novel idea in human genetics, namely to reconstruct the genome of a long dead individual using genetic data available through his descendants. The individual in question is Hans Jonatan, a slave of mixed ancestry who was born in St. Croix in 1784. His mother was African and his father although unknown was most probably his owner Ludvig von Schimmelmann, governor of the Danish West Indies at the time. Hans Jonatan had a particularly unique story. In 1788 he was brought to Denmark as one of several enslaved servants in the Schimmelmann household. Here he was given a special status with the family until General Schimmelmann died in 1794. Now managed by the general’s widow, who mistreated the young boy, Hans Jonatan absconded to the navy in 1801 where he fought in the Napoleonic Wars and excelled himself in battle. Unsuccessful in claiming his freedom from the Schimmelmann widow, upon his return – in spite of his service to the nation and a lengthy legal case – Hans Jonatan fled to Iceland in 1816 where he settled and eventually married Katrín Antoníusdóttir. The couple had two children from whom there are currently 500 descendants in the Icelandic population today.
Scientists at deCODE have already genotyped roughly 40,000 Icelanders using microarrays and have developed a novel long-range phasing algorithm based on the detection of shared chromosome segments that are identical by descent to determine both allelic phase and parental origin of entire chromosomes. We plan to use this revolutionary method to reconstruct large fragments of Hans Jonatan’s genome based on the genetic data available through his descendants. More generally, this project aims to develop general methods to reconstruct the ancestral genomes from genotype data obtained from contemporary descendants.
Furthermore, we intend to use population genetic methods and the fact that there is almost no other African admixture in the Icelandic gene pool to identify the African part of Hans Jonatan’s genome that has been transmitted to his descendants. Once we have reconstructed as much of his genome as possible (fragment by fragment), we will use this virtual ancient genome to make inferences about his phenotype and biogeographical ancestry. This study will not only set new standards for the use of genetics in shedding light on the history and legacy of long dead individuals, but also provide a unique opportunity for empirical study of how a genome is gradually fragmented by recombination over time.