Genes, Culture, and Agriculture: an Example of Human Niche Construction
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Texas A&M University-San Antonio Digital Commons @ Texas A&M University- San Antonio History Faculty Publications College of Arts and Sciences 2012 Genes, Culture, and Agriculture: An Example of Human Niche Construction Michael J. O'Brien Texas A&M University-San Antonio, [email protected] K. N. Laland Follow this and additional works at: https://digitalcommons.tamusa.edu/hist_faculty Part of the Anthropology Commons Repository Citation O'Brien, Michael J. and Laland, K. N., "Genes, Culture, and Agriculture: An Example of Human Niche Construction" (2012). History Faculty Publications. 12. https://digitalcommons.tamusa.edu/hist_faculty/12 This Article is brought to you for free and open access by the College of Arts and Sciences at Digital Commons @ Texas A&M University- San Antonio. It has been accepted for inclusion in History Faculty Publications by an authorized administrator of Digital Commons @ Texas A&M University- San Antonio. For more information, please contact [email protected]. 434 Current Anthropology Volume 53, Number 4, August 2012 Genes, Culture, and Agriculture An Example of Human Niche Construction by Michael J. O’Brien and Kevin N. Laland Theory and empirical data from a variety of disciplines strongly imply that recent human history involves extensive gene-culture coevolution, much of it as a direct result of human agricultural practices. Here we draw on niche- construction theory (NCT) and gene-culture coevolutionary theory (GCT) to propose a broad theoretical framework (NCT-GCT) with which archaeologists and anthropologists can explore coevolutionary dynamics. Humans are enormously potent niche constructors, and understanding how niche construction regulates ecosystem dynamics is central to understanding the impact of human populations on their ecological and developmental environments. We use as primary examples the evolution of dairying by Neolithic groups in Europe and Africa and the rise of the “sickle-cell allele” among certain agricultural groups in West Africa and suggest that these examples are broadly representative of much of human recent history. Although the core aspects of these case studies are familiar, we lay out the examples with a specific NCT-GCT focus, which allows us to highlight how archaeology, when coupled with genetic research, can play an important role in better understanding human history. Finally, we suggest that the NCT-GCT perspective is likely to be of widespread general utility because it inherently promotes consideratiwon of the active agency of humans, and other organisms, in modifying their ecological and developmental niches and naturally draws attention to the various forms of feedback that flow from human activities at multiple levels, in multiple populations, and across multiple species. Genes, Niches, and Agriculture more complex questions concerning the appearance of ag- riculture, including why people began to domesticate plants Perhaps no topic has received more attention in anthropology and animals in the first place (O’Brien and Wilson 1988; than the origins of agriculture—what Kareiva et al. (2007: Richerson, Boyd, and Bettinger 2001; Rindos 1984; Rowley- 1866) single out as perhaps “the single most important feature Conwy and Layton 2011; Zeder 2012). How did they cope of the human domination of our planet” and Bleed (2006:8) with the unintended by-products of entering the agricultural calls “one of anthropology’s most enduring challenges.” With niche, including high labor costs, high rates of failure, in some respect to the “what, when, and where” questions (B. D. Smith cases no clear economic incentive, and above all, more than 2007b) of agriculture, it is now recognized that there were occasional ill effects on health? Are these effects strictly phe- multiple core areas of plant domestication—anywhere be- notypic, meaning that they can be reversed through such tween seven and 10, depending on who is doing the counting things as dietary change, or are some of them genetic, meaning (e.g., B. D. Smith 1998; Vavilov 1992; Zeder et al. 2006). that selection, through agriculture, has reached beyond the Agriculture also includes the domestication of animals for any phenotype to modify selection and leave its mark on the number of purposes: as sources of food, especially meat and human genome? We agree with Zeder (2006b) that the history milk; as sources of products such as hides and wool; and for of domestication and agricultural origins comprises complex the protection, work, and even companionship they offer regional puzzles shaped in unique ways by dynamic macro- (Shipman 2010). Animals, like plants, exhibit highly localized and microforces, including climate change, opportunities, and areas of domestication (Zeder et al. 2006). constraints at the sociopolitical level, resource availability, and The logistical questions of what, when, and where lead to population levels. Our approach to handling these factors is based in niche- construction theory (NCT), a young branch of evolutionary Michael J. O’Brien is Professor in the Department of Anthropology biology that places emphasis on the capacity of organisms to and Dean of the College of Arts and Science at the University of Missouri (317 Lowry Hall, Columbia, Missouri 65211, U.S.A. modify natural selection in their environment and thereby [[email protected]]). Kevin N. Laland is Professor in the act as codirectors of their own evolution as well as that of School of Biology at the University of St. Andrews (Bute Medical others. Although it had its origin in population genetics, NCT Building, Queen’s Terrace, St. Andrews, Scotland KY16 9TS, United has become a multidisciplinary movement, involving evolu- Kingdom). This paper was submitted 1 X 10 and accepted 10 V 11. tionary biologists, ecologists, psychologists, anthropologists, ᭧ 2012 by The Wenner-Gren Foundation for Anthropological Research. All rights reserved. 0011-3204/2012/5304-0003$10.00. DOI: 10.1086/666585 O’Brien and Laland Genes, Culture, and Agriculture 435 archaeologists, computer scientists, philosophers, and others nificant components of their world. Organisms do more than (Kendal, Tehrani, and Odling-Smee 2011). Our approach also passively make their living in that hyperspace. They modify incorporates gene-culture coevolutionary theory (GCT), their niches, and/or those of other organisms, through their which explores how cultural and genetic processes interact metabolism, activities, and choices (Laland et al. 2011; Le- over evolutionary time. Anthropologists have long known the wontin 1983; Odling-Smee, Laland, and Feldman 2003). Ex- power that culture exerts in shaping the human condition, amples of niche construction include animals manufacturing but it is becoming increasingly clear that the interactions of nests, burrows, and webs and provisioning those sites for their genes and culture—literally, their coevolution—offer a faster offspring; plants changing levels of atmospheric gases and and stronger mode of human evolution than either by itself modifying nutrient cycles; fungi decomposing and/or storing (Ehrlich 2000; Ihara 2011; Laland 2008; Laland, Odling-Smee, organic matter; and bacteria fixing nutrients. and Myles 2010; Rendell, Fogarty, and Laland 2011; Richerson Ecologists and evolutionary biologists have long recognized and Boyd 2005; Richerson, Boyd, and Henrich 2010). the complex interplay of animal behavior and the physical In our view, nowhere has gene-culture coevolution hap- environment, with Mayr (1973:388) claiming that behavior pened faster than within agricultural societies. We propose is “perhaps the strongest selection pressure operating in the that the NCT-GCT approach to the evolution and develop- animal kingdom.” Despite this recognition, it is difficult to ment of agriculture provides numerous opportunities to link escape the feeling that standard evolutionary theory treats the the findings of human genetics with those of anthropologists interplay as unidirectional, where “adaptation is always asym- and archaeologists and to generate novel hypotheses about metrical; organisms adapt to their environment, never vice human evolution (Gerbault et al. 2011; Itan et al. 2009; Laland versa” (Williams 1992:484). Thus, with some exceptions, stan- and O’Brien 2010; Laland, Odling-Smee, and Myles 2010; dard theory holds that “the environment ‘poses the problem’; Richerson, Boyd, and Henrich 2010). We begin with a dis- the organisms ‘posit solutions,’ of which the best is finally cussion of NCT and how it can be used to structure empirical ‘chosen’” (Lewontin 1983:276). This standard theory is fine research in anthropology and archaeology. As humans are as far as it goes, but it fails to emphasize the fact that the enormously potent niche constructors, understanding how selective environments of organisms are themselves partially niche construction regulates ecosystem dynamics is central to built by the niche-construction activities of organisms. Thus, understanding the impact of human populations on their “organisms do not adapt to their environments; they con- environments. We then briefly discuss GCT, outlining some struct them out of the bits and pieces of the external world” of the tenets that guide its application, before considering (Lewontin 1983:280). That organisms in general, and humans how NCT and GCT can be used to better understand human in particular, modify their environment is no more news for behavior and evolution in the agricultural niche. We use as anthropologists than it is for biologists,