SOCIETY × GENETICS

An Atrocity Written in DNA

16th to 19th centuries

History · Early Modern · Holocene · Meghalayan

Shipping ledgers account for an estimated 12.5 million Africans forcibly deported across the Atlantic between the 16th and 19th centuries. The DNA of more than fifty thousand people on both sides of that ocean, read against those ledgers, largely mirrors the documented routes; where it diverges, it testifies to what the documents leave out: unequal survival, forced movements within the Americas, and an African ancestry passed down more by women than by men, under coercion, in proportions geneticists still dispute.

Why it matters

Genetics here serves as an archive for people whom the written record reduced to cargo counts. Tens of millions of living descendants can trace the trade's geography in their own ancestry, back to regions the ledgers name only as ports. The method's published corrections matter too: measuring atrocity demands the same rigour as any science, and gets it.

Dating & uncertainty

The transatlantic trade ran from the early 1500s to the 1860s, deporting an estimated 12.5 million people; the anchor sits mid-course. Genetic inferences about regional origins and sex bias carry real uncertainties, and published corrections to the largest of these studies are among the sources cited here.

Sources

1. Micheletti et al. (2020), American Journal of Human Genetics · Genetic consequences of the transatlantic slave trade in the Americasdoi:10.1016/j.ajhg.2020.06.012
2. Fortes-Lima & Verdu (2021), Human Molecular Genetics · Anthropological genetics perspectives on the transatlantic slave tradedoi:10.1093/hmg/ddaa271
3. Pfennig & Lachance (2023), American Journal of Human Genetics · Challenges of accurately estimating sex-biased admixture from X chromosomal and autosomal ancestry proportionsdoi:10.1016/j.ajhg.2022.12.012

Our species’ history as one day

23:58:031 min 57 s before midnight

if the 315,000 years of Homo sapiens were compressed into a single day