skip to main content

Title: Early isotopic evidence for maize as a staple grain in the Americas
Maize is a cultigen of global economic importance, but when it first became a staple grain in the Americas, was unknown and contested. Here, we report direct isotopic dietary evidence from 52 radiocarbon-dated human skeletons from two remarkably well-preserved rock-shelter contexts in the Maya Mountains of Belize spanning the past 10,000 years. Individuals dating before ~4700 calendar years before present (cal B.P.) show no clear evidence for the consumption of maize. Evidence for substantial maize consumption (~30% of total diet) appears in some individuals between 4700 and 4000 cal B.P. Isotopic evidence after 4000 cal B.P. indicates that maize became a persistently used staple grain comparable in dietary significance to later maize agriculturalists in the region (>70% of total diet). These data provide the earliest definitive evidence for maize as a staple grain in the Americas.
Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
Award ID(s):
1632061
Publication Date:
NSF-PAR ID:
10209148
Journal Name:
Science Advances
Volume:
6
Issue:
23
Page Range or eLocation-ID:
eaba3245
ISSN:
2375-2548
Sponsoring Org:
National Science Foundation
More Like this
  1. Maize (Zea mays ssp. mays) domestication began in southwestern Mexico ~9,000 calendar years before present (cal. BP) and humans dispersed this important grain to South America by at least 7000 cal. BP as a partial domesticate. South America served as a secondary improvement center where the domestication syndrome became fixed and new lineages emerged in parallel with similar processes in Mesoamerica. Later, Indigenous cultivators carried a second major wave of maize southward from Mesoamerica, but it is unclear whether the deeply divergent maize lineages underwent any subsequent gene flow between these regions. Here we report ancient maize genomes (2,300-1,900 cal. BP) from El Gigante rock-shelter, Honduras, that are closely related to ancient and modern maize from South America. Our findings suggest that genetic material from long-divergent South American maize was reintroduced to Central America. Direct radiocarbon dates and cob morphological data from the rock-shelter suggest that more productive maize varieties developed between 4,300 and 2,500 cal BP. We hypothesize that the hybridization of South and Central American maize may have been a source of genetic diversity and hybrid vigor as maize was becoming a staple grain in Central- and Meso- America.
  2. Abstract Data from rock shelters in southern Belize show evidence of tool making, hunting, and aquatic resource exploitation by 10,500 cal b.c. ; the shelters functioned as mortuary sites between 7600 and 2000 cal b.c. Early Holocene contexts contain stemmed and barbed bifaces as part of a tradition found broadly throughout the neotropics. After around 6000 cal b.c. , bifacial tools largely disappear from the record, likely reflecting a shift to increasing reliance on plant foods, around the same time that the earliest domesticates appear in the archaeological record in the neotropics. We suggest that people living in southern Belize maintained close ties with neighbors to the south during the Early Holocene, but lagged behind in innovating new crops and farming technologies during the Middle Holocene. Maize farming in Belize intensified between 2750–2050 cal b.c. as maize became a dietary staple, 1000–1300 years later than in South America. Overall, we argue from multiple lines of data that the Neotropics of Central and South America were an area of shared information and technologies that heavily influenced cultural developments in southeastern Mesoamerica during the Early and Middle Holocene.
  3. Abstract The genetic prehistory of human populations in Central America is largely unexplored leaving an important gap in our knowledge of the global expansion of humans. We report genome-wide ancient DNA data for a transect of twenty individuals from two Belize rock-shelters dating between 9,600-3,700 calibrated radiocarbon years before present (cal. BP). The oldest individuals (9,600-7,300 cal. BP) descend from an Early Holocene Native American lineage with only distant relatedness to present-day Mesoamericans, including Mayan-speaking populations. After ~5,600 cal. BP a previously unknown human dispersal from the south made a major demographic impact on the region, contributing more than 50% of the ancestry of all later individuals. This new ancestry derived from a source related to present-day Chibchan speakers living from Costa Rica to Colombia. Its arrival corresponds to the first clear evidence for forest clearing and maize horticulture in what later became the Maya region.
  4. Radiocarbon dating of the earliest occupational phases at the Cooper’s Ferry site in western Idaho indicates that people repeatedly occupied the Columbia River basin, starting between 16,560 and 15,280 calibrated years before the present (cal yr B.P.). Artifacts from these early occupations indicate the use of unfluted stemmed projectile point technologies before the appearance of the Clovis Paleoindian tradition and support early cultural connections with northeastern Asian Upper Paleolithic archaeological traditions. The Cooper’s Ferry site was initially occupied during a time that predates the opening of an ice-free corridor (≤14,800 cal yr B.P.), which supports the hypothesis that initial human migration into the Americas occurred via a Pacific coastal route.
  5. This article reports new carbon, nitrogen, and sulfur isotope data for 10 individuals on the San Francisco Peninsula from CA-SMA-78 (Hamilton Mound 20; n = 6), CA-SMA-160 (Hiller Mound; n = 3), and a previously unrecorded site in downtown San Mateo (n = 1). We also report seven new bone collagen accelerator mass spectrometry radiocarbon dates, three from CA-SMA-78 that fall during the Early-Middle Transition and early Middle Period (ca. 2,400 and 1,700 cal BP), three from CA-SMA-160 that fall during the late Middle and Middle-Late Transition periods (ca. 1,080 and 770 cal BP), and one from the unrecorded site that falls during the Late Middle Period (ca. 1,260 cal BP). Dietary isotopes show a bimodal pattern, with most individuals (n = 8) consuming a mixed marine-terrestrial diet and two a terrestrial-dominant diet (n = 2). We propose two hypotheses to explain this variation, the first suggesting independent family-level hunting and gathering territories combined with little intra-group sharing of food, and the second suggesting exogamous marriage patterns with people migrating from regions to the south. Future isotopic research could provide support for one (or both) of these hypotheses.