The AAPA Statement on Race and Racism was written by the AAPA subcommittee tasked with revising the previous AAPA statement on the Biological Aspects of Race that was published in the American Journal of Physical Anthropology, vol. 101, pp 569‐570, 1996. The Committee on Diversity (COD) subcommittee was comprised of (in alphabetical order): Rebecca Ackermann, Sheela Athreya, Deborah Bolnick, Agustín Fuentes (chair), Tina Lasisi, Sang‐Hee Lee, Shay‐Akil McLean, and Robin Nelson. The statement was unanimously accepted by the AAPA Executive Committee at its meeting on March 27, 2019 at the 88th Annual Meeting in Cleveland, Ohio and is available on the AAPA website at http://physanth.org/.
Like many highly variable human traits, more than a dozen genes are known to contribute to the full range of skin color. However, the historical bias in favor of genetic studies in European and European-derived populations has blinded us to the magnitude of pigmentation’s complexity. As deliberate efforts are being made to better characterize diverse global populations and new sequencing technologies, better measurement tools, functional assessments, predictive modeling, and ancient DNA analyses become more widely accessible, we are beginning to appreciate how limited our understanding of the genetic bases of human skin color have been. Novel variants in genes not previously linked to pigmentation have been identified and evidence is mounting that there are hundreds more variants yet to be found. Even for genes that have been exhaustively characterized in European populations like MC1R, OCA2, and SLC24A5, research in previously understudied groups is leading to a new appreciation of the degree to which genetic diversity, epistatic interactions, pleiotropy, admixture, global and local adaptation, and cultural practices operate in population-specific ways to shape the genetic architecture of skin color. Furthermore, we are coming to terms with how factors like tanning response and barrier function may also have influenced selection on skin throughout human history. By examining how our knowledge of pigmentation genetics has shifted in the last decade, we can better appreciate how far we have come in understanding human diversity and the still long road ahead for understanding many complex human traits.
Hair is predominantly a proteinaceous fiber that originates from hair follicles located within the subcutis and/or dermis of the skin. It is one of the defining features of mammals, serving important functions, such as thermoregulation and endothermy. Among mammals, humans are exceptional in lacking a full covering of body hair. Instead the growth of terminal hairs is limited to specific body regions, such as the scalp, axillae, and groin. Our aim in this chapter is to provide an overview of the anthropology of human scalp hair. We will explore approaches to the study of variation in human scalp hair phenotypes, as well as the genetic and evolutionary basis of this diversity. The biology of human scalp hair, with emphasis on quantitative and qualitative differences among populations, as well as impact on hair grooming practices will also be discussed.