In an incredible feat, the first genome of a dead human has been reconstructed without any remains. Hans Jonatan’s physical remains are long-gone but his DNA isn’t — it is alive in each of his descendants. As the first person of colour in Iceland in 1802, his genetics are easy to trace and, amazingly, we can even know which part of Africa his mother was taken from.

The man

Hans Jonatan is a very interesting man in his own right. He was born in the Caribbean in 1784 to Emilia Regina, a black “house slave”, and fathered by a white Dane. Hans and Emilia were both owned by the Schimmelman family. The family then moved to Denmark when their plantation wasn’t so successful.

The man of the house died, bequeathing Hans to his wife. Hans escaped and fought for the Danish army in the Napoleonic War. Afterwards, he declared himself a free man because of his service to the country and because slavery was illegal in Denmark, although it was legal in the Danish West Indies. It was a landmark legal case for European slavery. He lost the case and was ordered on March 31, 1802 to return to the West Indies. He escaped to Iceland and became a merchant and peasant farmer. He married and raised two children before his death in 1827. A book has been written about him by Gisli Palsson, called The Man Who Stole Himself.

Hans Jonatan. Image credits: Fox News/YouTube.

The genome

Because Hans’ DNA was unique in Iceland, his genome was able to be reconstructed. Luckily, Iceland has a comprehensive genome database for its residents. A genome is a mosaic of chromosome fragments from ancestors who lived sometime in the past. So Hans’ descendants still have his chromosome fragments.

788 of Hans’ descendants were identified, and 182 of them were tested using SNPs (single-nucleotide polymorphisms to identify DNA variations). The whole genomes of 20 descendants were sequenced. The researchers had 674 chromosome fragments that were possibly linked to Hans’ African heritage. They used this information plus genealogical records and divergent ancestry to reconstruct Hans’ genome.

“To our knowledge, this study demonstrates the first use of genotype data from contemporary individuals, along with information about their genealogical relationships, to reconstruct a sizeable portion of the genome from a single ancestor born more than 200 years ago,” says the international team of researchers in their paper.

The researchers were able to construct 38% of Hans’ maternal genome using further genetic analysis and genealogy checks. Emilia was originally from the Benin, Nigeria, and Cameroon regions. She or her parents were probably transported as slaves between 1760 and 1790. The researchers remarked that it was surprisingly easy to construct the 200-year-old genome with the right data.

Journal reference: Anuradha Jagadeesan et al. 2018. Reconstructing an African haploid genome from the 18th century. Nature Genetics.