In:
Science, American Association for the Advancement of Science (AAAS), Vol. 381, No. 6657 ( 2023-08-04)
Abstract:
Genetic analysis of historical individuals has the potential to help restore knowledge of people whose stories were omitted from written records. During the late 18th and early 19th centuries, Catoctin Furnace in Maryland relied on a workforce of enslaved individuals to operate the iron furnace and carry out domestic and agricultural tasks. Despite the role that Catoctin Furnace played in early US history (including supplying munitions during the Revolutionary War), relatively little is known about the African Americans who labored there or their descendants compared with the furnace’s later, predominantly white workforce. RATIONALE We produced genome-wide data for 27 individuals buried in the Catoctin Furnace African American Cemetery and compared them to ~9.3 million consenting research participants genotyped by 23andMe, Inc., to address the following questions: (i) How were the Catoctin individuals related to each other? (ii) What were the sources of their African and European ancestry? (iii) Where in the US do their genetic relatives live today, including their direct descendants? (iv) What can their genomes reveal about their health? RESULTS We identified five genetic families, consisting of biological mothers, children, and siblings, among the Catoctin individuals. In most cases, biological family members were buried in close proximity. All but one of the Catoctin individuals had primarily African ancestry, with variable amounts of European ancestry. To learn more about their ancestry, we developed an approach to detect identical-by-descent segments of the genome shared between the Catoctin individuals and 23andMe research participants. Identical-by-descent segments of DNA are shared by two or more people because they have been inherited from a recent common ancestor. We identified 41,799 close and distant relatives of the Catoctin individuals among 23andMe research participants. Within Africa, we found the highest rates of genetic sharing between Catoctin individuals and research participants who self-identified as belonging to the Wolof or Kongo ethnolinguistic groups. Within Europe, we observed the highest rates of genetic sharing with research participants that have ties to Great Britain and Ireland. Within the US, participants from the South showed elevated rates of sharing, largely reflecting distant connections to 23andMe research participants with sub-Saharan African ancestry (possibly tracing back to shared common ancestors in Africa). When we considered genetic relatives who share the most identical DNA with the Catoctin individuals, we observed the highest rates of sharing in Maryland, suggesting that at least some descendants stayed in the region after the furnace’s transition away from enslaved and paid African American labor. Finally, we found that some of the Catoctin individuals carried risk factors for sickle cell anemia and glucose-6-phosphate dehydrogenase deficiency, genetic diseases that are common in African Americans today. CONCLUSION These results demonstrate the power of joint analysis of DNA from historical individuals and the extremely large datasets generated through direct-to-consumer ancestry testing, and they serve as a model for obtaining direct insights into the genome-wide genetic ancestry of enslaved people in the historical US. Genetic connections to individuals from Catoctin Furnace African American Cemetery in Maryland. A timeline highlighting major events in the history of Catoctin Furnace and the birth years of research participants in the 23andMe cohort, presented alongside maps showing the proportion of 23andMe research participants associated with geographic coordinates in the US, sub-Saharan Africa, and Europe who share genetic connections to the Catoctin individuals.
Type of Medium:
Online Resource
ISSN:
0036-8075
,
1095-9203
DOI:
10.1126/science.ade4995
Language:
English
Publisher:
American Association for the Advancement of Science (AAAS)
Publication Date:
2023
detail.hit.zdb_id:
128410-1
detail.hit.zdb_id:
2066996-3
detail.hit.zdb_id:
2060783-0
SSG:
11
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