Pre-Columbian Sunflower Domestication in Mexico
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This document summarizes an academic debate around the origins of domesticated sunflower. Some researchers argue that sunflower was independently domesticated in Mesoamerica based on archaeological evidence of early domesticated sunflower remains in Mexico. However, others critique this evidence and argue the molecular and linguistic evidence supports a single origin of domesticated sunflower in Eastern North America. The debate examines archaeological, linguistic, ethnographic and molecular DNA evidence on both sides of this issue.
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Pre-Columbian Sunflower Domestication in Mexico
- 1. Sunflower as a Pre- Columbian Domesticate in Mexico Images from Google Images
- 2. • The extant cultivated sunflower, Helianthus annuus is thought to be independently domesticated in eastern North America • Recent archaeological evidences in Mexico urged several researchers to look for sunflower domestication in Mesoamerican regions • The facts have been much debated
- 3. Evidences of Mesoamerican Domestication • Three lines of evidences proposed by Lentz et al. (2008) - Archaelogical data - Linguistic and ethnographic data - Ethnohistorical data
- 4. Archaelogical Evidences • Several wild sunflower species are native to Mexico • Pre-Columbian archaeological remains of wild sunflower • In coprolites in Ocampo Cave, Tamaulipas, Mexico: 2900-2200 cal B.C. • 10 achenes from wild annuus at Tenochtitlan, Mexico
- 5. Archaelogical Evidences • Early domesticated sunflower remains San Andres site in Tabasco, Mexico • An achene (2867-2482 cal B.C.) and a seed (2875-2575 cal B.C.) Predates all the archeological sunflower remains
- 6. Archaelogical Evidences Cueva del Gallo, Morelos, Mexico • Three large achenes (~ 290 cal B.C.) • Characteristic domestication syndromes: - Twist in the fruit from crowded domesticated sunflower head - Biggest of all excavated sunflower achenes; outside of wild sunflower dimentions
- 7. Mexican dissemules represent a distinct lineage from eastern North American sunflower populations
- 8. Smith’s Letter • Archeological evidences for domesticated sunflower in pre- Columbian Mesoamerica are inadequate - No plant remains other than seeds and achenes - Taxonomic problems: Santa Leticia achene misclassified - Insufficient morphological descriptors - 3 Morelos specimens may represent introduced domesticated sunflower Despite smaller sample size, San Andres specimens represent earliest fully domesticated sunflower Paleoethnobotany is recent and/or Mexican sites are not favorable Santa Leticia is outside of wild sunflower locale PNAS reviewers “scrutinized” the facts Mexican domestication may predate eastern North American domestication and Lentz’s Reply
- 9. Linguistic and Ethnographic Data • Distinctive names and lack of phonetic resemblance to the Spanish terms suggests pre-Columbian existence
- 10. Brown’s Letter • Linguistic evidence is severely deficient to suggest sunflower as an pre-Columbian domesticate in Mesoamerica - Semantically transparent names are commonplace - Mesoamerican names generated from ancestral languages Sunflower doesn’t have one in proto-languages of earlier peroids - No record of an word for sunflower in primitive languages of Mesoamerica The linguistic evidence and archaeological data together demonstrate the use of domesticated sunflower in pre- Columbian times So, what would be the cultigen called if there was no word for sunflower? and Lentz’s Reply
- 11. Ethnohistoric Data • Chimalacatl/chimalxochitl/chimalsu chitl represents sunflower in modern indigenous Nahua (the Aztecs) group • Spanish conquerors documented presence of sunflower in indigenous Aztecs • Sahagun’s Florentine Codex illustrates sunflower as a symbol representing shield • Rulers carried jeweled sunflowers Portrait: Netzahaulapilli, the Aztec ruler of Tetcoco
- 12. Heiser Lentz Don’t look like sunflowers Can’t be anything else Large receptacle Long peduncle Ray and disk florets Big flowers Labeled as “chimalsuchitl”
- 13. Heiser’s Letter • Historical records suggesting pre-Columbian domestication of sunflower in Mesoamerica is altogether lacking - Same nomenclature was used to represent more than one plant The historical records presented are relevant Not all drawings are from original artists Printers shared illustrations and Lentz’s Reply
- 14. Why Mesoamerican domesticate remained so obscure? • Independent Eastern North American domestication model was widely accepted Lack of archaeological evidences: • Archaeologically unfavorable environment in the neotropical regions • A lag in paleoethnobotanical research Not much exploited as North American domesticate: • More a symbolic than direct feed source • Predominance of alternative fat sources in Mesoamerican diets • Not extensively grown • Spanish conquest suppressed symbolic assets of indigenous people Mesoamerican landraces have not been scrutinized the way their North American counterparts have been
- 15. DNA evidences: the “ultimate truth” - Two references to the molecular studies: 1. Harter AV, et al. (2004) Origin of extant domesticated sunflowers in eastern North America. Nature 430:201-205 1. Wills DM, Burke JM (2006) Chloroplast DNA variation confirms a single origin of domesticated sunflower (Helianthus annuus L.). J Hered 97:403-408
- 16. Harter AV, et al. (2004) Origin of extant domesticated sunflowers in eastern North America. Nature 430:201-205 • Primers flanking 18 microsatellite markers spanning sunflower genome • 21 wild H. annuus, 8 Native American and Mexican landraces, and two elite cultivars • STRUCTURE analysis • “Extant germplasm arose from wild populations in the central USA”
- 17. Wills DM, Burke JM (2006) Chloroplast DNA variation confirms a single origin of domesticated sunflower (Helianthus annuus L.). J Hered 97:403-408 • Primers flanking 6 polymorphic cpSSR markers • 26 wild H. annuus, 15 domesticated lines • Chloroplast haplotypes were analyzed • “Single origin of the extant domesticated sunflowers outside of Mexico”
- 18. Rieseberg and Burke’s Letter • All available molecular data are suggestive of a single origin outside of Mexico - Mexican landraces that had conspicuous uniqueness to their phenotypes shared chloroplast haplotypes of the US domesticates - Bigger achenes of Mexican remains do not preclude North American dissemination Molecular studies have not ventured Mexican domesticates Might have hybridized with modern varieties and Lentz’s Reply
- 19. Thank You
- 20. Bibliography • Brown CH. 2008. A Lack of Linguistic Evidence for Domesticated Sunflower in Pre-Columbian Mesoamerica. PNAS 105(30):E47 • Harter AV, et al. 2004. Origin of Extant Domesticated Sunflowers in Eastern North America. Nature 430:201-205. • Heiser CB. 2008. How Old is the Sunflower in Mexico? PNAS 105(30):E48. • Lentz DL, et al. 2001. Prehistoric Sunflower (Helianthus annuus L.) Domestication in Mexico. Econ Bot 53(3):370-376. • Lentz DL, et al. 2008. Reply to Rieseberg and Burke, Heiser, Brown, and Smith: Molecular, Linguistic, and Archaelogical Evidence for Domesticated Sunflower in Pre-Columbian Mesoamerica. PNAS 105(30):E49-E40. • Rieseberg L and JM Burke. 2008. Molecular Evidence and the Origin of the Domesticated Sunflower. PNAS 105(30):E46. • Smith BD. 2008. Winnowing the Archaeological Evidence for Domesticated Sunflower in Pre- Columbian Mesoamerica. PNAS 105(30):E45 • Wills, DM and JM Burke. 2006. Chloroplast DNA Variation Confirms a Single Origin of Domesticated Sunflower (Helianthus annuus L.). J Hered 97(4):403-408.