So many Nigerians: why is Nigeria overrepresented as the ancestral genetic homeland of Legacy African North Americans?

The genetics of African North Americans are complex amalgamations of various West and Central African peoples with modest gene flow from specific European and Amerindian peoples. A comprehensive understanding of African North American biohistory is a prerequisite for accurate interpretations of the ancestral genetics of this population. Too often, genetic interpretations falter with ahistorical reconstructions. The recently reported overrepresentation of Nigerian lineages in African North Americans reflects pronounced limitations in the African genomic database, the artificiality of the colonial maps of Africa, the contributions of multiple African empires and kingdoms into the transatlantic trade in enslaved Africans, and the overrepresentation of Yoruba peoples in the existing limited representation of West Africans in public genomic databases. This Matters Arising paper is in response to Micheletti et al. (2020), published in The American Journal of Human Genetics. See also the response by Micheletti et al. (2020), published in this issue.

Evolutionary perspectives on African North American genetic diversity: Origins and prospects for future investigations.

African-descended peoples of the Americas represent an amalgamation of West, Central, and Southeast African regional and ethnic groups with modest gene flow from specific non-African populations. Despite 16+ generations of residence in the Americas, there is a deficit of evolutionary knowledge about these populations. Focusing on Legacy African American, the African North American descendants of survivors of the transatlantic trade in enslaved Africans, we report on emic evolutionary perspectives of their self-identity gleaned from our interviews of 600 individuals collected over 2 years. Gullah-Geechee peoples of Carolina Coastal regions are a model case study due to their historical antiquity, substantial African retentions, relative geospatial isolation, and proposed progenitor status to other Legacy African American microethnic groups. We identify salient research questions for future studies that will begin to bridge the evolutionary gaps in our knowledge of these diverse peoples and the historical evidence for specific evolutionary processes.

Historical overview, current research, and emerging bioethical guidelines in researching the New York African burial ground.

OBJECTIVES: The issues addressed in this article are those related to the bioethical actions and decisions surrounding the excavation of the New York African Burial Ground (NYABG) in the 1990s, the significance of conducting research on historical African/African American remains, and the eminence of protecting newly discovered African American burial sites in the future for research purposes. MATERIALS AND METHODS: Skeletal (n = 419, at the time of excavation) and soil (n = 92) remains of the 17th and 18th century New York African Burial Ground were used to discuss the necessity of research on historical African/African American remains. DISCUSSION: Studying the remains of enslaved Africans is critical to understanding the biological processes and existence of all people. Researching the NYABG site, the oldest and largest burial site of free and enslaved Africans, illuminates the necessity and significance of scientific research on other historical African/African American cemeteries throughout the nation. The results of future research will provide a more profound sense of identity for a group of people who were forcefully severed from their genetic and cultural origins. This research will increase the representation of African descended people in genomic, anthropological, and cultural research, and ultimately help researchers to learn more about the origins of all humans.

Conceptual shifts needed to understand the dynamic interactions of genes, environment, epigenetics, social processes, and behavioral choices.

Social and behavioral research in public health is often intimately tied to profound, but frequently neglected, biological influences from underlying genetic, environmental, and epigenetic events. The dynamic interplay between the life, social, and behavioral sciences often remains underappreciated and underutilized in addressing complex diseases and disorders and in developing effective remediation strategies. Using a case-study format, we present examples as to how the inclusion of genetic, environmental, and epigenetic data can augment social and behavioral health research by expanding the parameters of such studies, adding specificity to phenotypic assessments, and providing additional internal control in comparative studies. We highlight the important roles of gene-environment interactions and epigenetics as sources of phenotypic change and as a bridge between the life and social and behavioral sciences in the development of robust interdisciplinary analyses.

Community-initiated genomics.

Ancient DNA is used to connect enslaved African Americans to modern descendants.

Identification of trace metals and potential anthropogenic influences on the historic New York African Burial Ground population: A pXRF technology approach.

The New York African Burial Ground (NYABG) is the country's oldest and largest burial site of free and enslaved Africans. Re-discovered in 1991, this site provided evidence of the biological and cultural existence of a 17th and 18th Century historic population viewing their skeletal remains. However, the skeletal remains were reburied in October 2003 and are unavailable for further investigation. The analysis of grave soil samples with modern technology allows for the assessment of trace metal presence. Portable X-ray fluorescence (pXRF) spectrometry provides a semi-quantitative and non-destructive method to identify trace metals of this population and in the surrounding environment. Sixty-five NYABG soil samples were analyzed on a handheld Bruker Tracer III- SD XRF with 40 kV of voltage and a 30µA current. Presence of As, Cu, and Zn can potentially decipher the influence of the local 18th Century pottery factories. Elevated levels of Sr validate the assumed heavy vegetative diets of poor and enslaved Africans of the time. Decreased levels of Ca may be due in part to the proximity of the Collect Pond, the existing water table until the early 19th Century, and Manhattan's rising sea level causing an elevated water table washing away the leached Ca from human remains. These data help us reconstruct the lives of these early Americans in what became New York City.

Gene-environment interactions in human health: case studies and strategies for developing new paradigms and research methodologies.

THE SYNERGISTIC EFFECTS OF GENES AND THE ENVIRONMENT ON HEALTH ARE EXPLORED IN THREE CASE STUDIES: adult lactase persistence, autism spectrum disorders, and the metabolic syndrome, providing examples of the interactive complexities underlying these phenotypes. Since the phenotypes are the initial targets of evolutionary processes, understanding the specific environmental contexts of the genetic, epigenetic, and environmental changes associated with these phenotypes is essential in predicting their health implications. Robust databases must be developed on the local scale to deconstruct both the population substructure and the unique components of the environment that stimulate geographically specific changes in gene expression patterns. To produce these databases and make valid predictions, new, locally focused, and information-dense models are needed that incorporate data on evolutionary ecology, environmental complexity, local geographic patterns of gene expression, and population substructure.

Ancestral links of Chesapeake Bay region African Americans to specific Bight of Bonny (West Africa) microethnic groups and increased frequency of aggressive breast cancer in both regions.

The high frequency of aggressive, early onset, and highly fatal breast cancer among Chesapeake Bay region African Americans suggests that there may be a contributing ancestral component. This study identifies the region's founding African, European, and Native American Indian populations using ethnogenetic layering and identifies the microethnic substructure of each founding continental aggregate. The largest component (38%) of the enslaved Africans brought to the Chesapeake Bay originally came from the coastal and hinterlands of the Bight of Bonny, a region with very high rates of aggressive, early onset breast cancer. Ethnogenetic layering is applied a second time to reveal the microethnic groups of the Bight of Bonny hinterlands with historical links to the Chesapeake Bay region. These analyses identify the specific microethnic groups within this region of Africa that may be the sources of relevant polymorphisms contributing to the etiology of aggressive breast cancer in the Chesapeake Bay. This report suggests a historical link between specific African microethnic groups and a US health disparity.

Illuminating cancer health disparities using ethnogenetic layering (EL) and phenotype segregation network analysis (PSNA).

BACKGROUND: Resolving cancer health disparities continues to befuddle simplistic racial models. The racial groups alluded to in biomedicine, public health, and epidemiology are often profoundly substructured. METHODS: EL and PSNA are computational assisted techniques that focus on microethnic group (MEG) substructure. RESULTS: Geographical variations in cancer may be due to differences in MEG ancestry or similar environmental exposures to a recognized carcinogen. Examples include breast and prostate cancers in the Chesapeake Bay region and Bight of Biafra biological ancestry, hypertension and stroke in the Carolina Coast region and Central African biological ancestry, and pancreatic cancer in the Mississippi Delta region and dietary/medicinal exposure to safrol from Sassafras albidum.