Isotopic Confirmation of the Timing and Intensity of Maize Consumption in Greater Cahokia

Abstract

The history of maize (Zea mays L.) in the eastern Woodlands remains an important study topic. As currently understood, these histories appear to vary regionally and include scenarios positing an early introduction and an increase in use over hundreds of, if not a thousand, years. In this article, we address the history of maize in the American Bottom region of Illinois and its importance in the development of regional Mississippian societies, specifically in the Cahokian polity located in the central Mississippi River valley. We present new lines of evidence that confirm subsistence-level maize use at Cahokia was introduced rather abruptly at about AD 900 and increased rapidly over the following centuries. Directly dated archaeobotanical maize remains, human and dog skeletal carbon isotope values, and a revised interpretation of the archaeological record support this interpretation. Our results suggest that population increases and the nucleation associated with Cahokia were facilitated by the newly introduced practices of maize cultivation and consumption. Maize should be recognized as having had a key role in providing subsistence security that—combined with social, political, and religious changes—fueled the emergence of Cahokia in AD 1050.

Integrative analysis of DNA, macroscopic remains and stable isotopes of dog coprolites to reconstruct community diet

“…Coprolites have lower δ 15 N and higher δ 13 C values relative to those of collagen and apatite of human and dog Late Woodland and Terminal Late Woodland populations 54 , 74 – 77 (Supplemental Table 6 ), and also vary significantly between samples. The difference in stable isotope values between sample types is likely due to the fractionation of the dietary components: collagen reflects the isotopic composition of mainly the protein source, with δ 13 C consistently enriched by 5‰ and δ 15 N by 3–4‰ relative to diet 66 , 67 , while coprolites approximate the isotopic composition of whole diet, with δ 13 C depleted by ~ 0.9‰ and δ 15 N by 1‰ relative to diet 13 .…”

“…Stable isotope results from the coprolites suggest a diet of terrestrial fauna, fish with low δ 15 N and high δ 13 C values, and C 3 plants with the possible addition of C 4 plants such as maize and/or maygrass. Maize is absent from Late Woodland sites in the region and is only identified from Terminal Late Woodland contexts (post-dating AD 900 46 , 54 , 78 – 80 ), and maize was not identified in the DNA reads recovered from the coprolites. Explanations for the latter include: coprolite deposition preceded the introduction of maize (ca pre AD 900 54 ); the meals reflected did not include maize; or that maize DNA was too degraded to identify.…”

“…1050–1300 AD). However, while maize consumption accelerated rapidly after its initial introduction and continued into historic times, cultivation of most native crops declined and they eventually fell out of use 54 .…”

Molecular Parallelism Underlies Convergent Highland Adaptation of Maize Landraces

“…We then test for a linear relationship between X and the similarly transformed vector of elevations using the lm function in R [70] and control for the 29 tests done using Qvalue [71]. [18,19,20,21,22,23,24,25,26,27,28,29]. Figure S4: Ratio of co-directional and anti-directional SNPs in common neutral (NE) and outlier (OU) SNP set before and after correcting for 2dsfs.…”

“…Given its history, maize is an ideal model system to study parallel adaptation. Maize was first domesticated in the warm lowlands of the Balsas River Valley approximately 9,000 years ago [16,17], and subsequently spread to several independent highland regions, first to the the Mexican Central Plateau, and then to the highlands of the southwestern United States, Guatemala and the Andes [18,19,20,21,22,23,24,25,26,27,28,29]. While highland regions colonized by maize are far from identical, commonalities include a shorter growing season, low temperature, low partial pressure of atmospheric gases, and high ultraviolet radiation [30,31].…”