The diffusion of maize to the southwestern United States and its impact
Edited by Linda S. Cordell, University of Colorado, Boulder, CO, and approved October 30, 2009
Abstract
Our understanding of the initial period of agriculture in the southwestern United States has been transformed by recent discoveries that establish the presence of maize there by 2100 cal. B.C. (calibrated calendrical years before the Christian era) and document the processes by which it was integrated into local foraging economies. Here we review archaeological, paleoecological, linguistic, and genetic data to evaluate the hypothesis that Proto-Uto-Aztecan (PUA) farmers migrating from a homeland in Mesoamerica introduced maize agriculture to the region. We conclude that this hypothesis is untenable and that the available data indicate instead a Great Basin homeland for the PUA, the breakup of this speech community into northern and southern divisions ≈6900 cal. B.C. and the dispersal of maize agriculture from Mesoamerica to the US Southwest via group-to-group diffusion across a Southern Uto-Aztecan linguistic continuum.
Acknowledgments.
We are grateful for the logistical support provided by the Mexico-North Research Network and the University of Texas at San Antonio and for the research conducted by Desert Archaeology, Inc. We thank the Instituto Nacional de Antropología e Historia for permission to conduct archaeological field research in Mexico. Funding for this research was provided by National Science Foundation Grants SBR-9708610, SBR-9809839, SBR-0219185, and SBR-0220292, the National Geographic Society, the National Endowment for the Humanities, the Smithsonian's National Museum of Natural History, the University of Texas at San Antonio, the Arizona Department of Transportation, and the City of Tucson.
Supporting Information
Supporting Information (PDF)
Supporting Information
- Download
- 140.04 KB
References
1
, eds JE Staller, RH Tykot, BF Benz (Elsevier, Amsterdam Histories of Maize, 2006).
2
JB Mabry The Late Archaic across the Borderlands, ed BJ Vierra (Univ Texas Press, Austin, TX), pp. 41–83 (2005).
3
DR Piperno Behavioral Ecology and the Transition to Agriculture, eds DJ Kennett, B Winterhalder (Univ California Press, Berkeley, CA), pp. 137–166 (2006).
4
WH Wills Early Prehistoric Agriculture in the American Southwest (School of American Research Press, Santa Fe, NM, 1988).
5
PE Minnis The Origins of Agriculture, eds CW Cowan, PJ Watson (Smithsonian Institution Press, Washington, DC), pp. 121–141 (1992).
6
JB Mabry, JB Carpenter, G Sanchez Archaeology Without Borders, eds LD Webster, ME McBrinn (Univ Press of Colorado, Boulder, CO), pp. 155–183 (2008).
7
CF Berry, MS Berry Anthropology of the Desert West, eds CJ Condie, DD Fowler (Univ Utah Press, Salt Lake City, UT) Vol 110, 253–327, University of Utah Anthropological Papers. (1986).
8
P Bellwood Archaeology and Linguistics, eds P McConvell, N Evans (Oxford Univ Press, Melbourne), pp. 123–134 (1997).
9
JH Hill, Proto-Uto-Aztecan: A community of cultivators in central Mexico? Am Anthropol 103, 913–934 (2001).
10
P Bellwood, An archaeologist's view of language macrofamily relationships. Bull Indo-Pacific Prehistory Assoc 13, 46–60 (1993).
11
P Bellwood, Early agricultural population diasporas? Farming, languages, and genes. Annu Rev Anthropol 30, 181–207 (2001).
12
P Bellwood Areal Diffusion and Genetic Inheritance, eds AY Aikhenvald, RMW Dixon (Oxford Univ Press, Oxford), pp. 27–43 (2003).
13
J Diamond, P Bellwood, Farmers and their languages: The first expansions. Science 300, 597–603 (2003).
14
P Bellwood First Farmers (Blackwell, Oxford, 2005).
15
WR Miller, The classification of the Uto-Aztecan languages based on lexical evidence. Int J Am Linguist 50, 1–24 (1984).
16
M Cortina–Borjas, L Valiñas Coalla, Some remarks on Uto-Aztecan classification. Int J Am Linguist 55, 214–239 (1989).
17
L Campbell American Indian Languages (Oxford Univ Press, Oxford, 1997).
18
JH Hill Examining the Farming/Language Dispersal Hypothesis, eds P Bellwood, C Renfrew (McDonald Inst Archaeol Res, Cambridge, United Kingdom), pp. 331–340 (2002).
19
JH Hill, Toward a linguistic prehistory of the Southwest: “Azteco-Tanoan” and the arrival of maize cultivation. J Anthropol Res 58, 457–475 (2002).
20
JH Hill Memoirs of the Seventh International Conference on Linguistics in the Northwest (Translated from Spanish), eds MdC Morúa Leyva, RM Ortiz Ciscomani (Universidad de Sonora, Hermosillo) Vol 2, 59–81 (2004).
21
JH Hill Histories of Maize, eds JE Staller, RH Tykot, BF Benz (Elsevier, Amsterdam), pp. 631–645 (2006).
22
DG Smith, et al., Implications of the distribution of Albumin Naskapi and Albumin Mexico for New World prehistory. Am J Phys Anthropol 111, 557–572 (2000).
23
RG Matson Examining the Farming/Language Dispersal Hypothesis, eds P Bellwood, C Renfrew (McDonald Inst for Archaeol Res, Cambridge, United Kingdom), pp. 341–356 (2002).
24
SA LeBlanc Archaeology Without Borders, eds LD Webster, ME McBrinn (Univ Press of Colorado, Boulder, CO), pp. 107–142 (2008).
25
C Bronk Ramsey, Development of the radiocarbon calibration program OxCal. Radiocarbon 43, 355–363 (2001).
26
PJ Reimer, et al., IntCal04 terrestrial radiocarbon age calibration, 0–26 cal kyr bp. Radiocarbon 46, 1029–1058 (2004).
27
BF Benz, A Long, Prehistoric maize evolution in the Tehuacan Valley. Curr Anthropol 41, 459–465 (2000).
28
M Blake Histories of Maize, eds JE Staller, RH Tykot, BF Benz (Elsevier, Amsterdam), pp. 55–72 (2006).
29
DR Piperno, AJ Ranere, I Holst, J Iriarte, R Dickau, Starch grain and phytolith evidence for early ninth millennium b.p. maize from the central Balsas River Valley, Mexico. Proc Natl Acad Sci USA 106, 5019–5024 (2009).
30
DR Piperno, KV Flannery, The earliest archaeological maize (Zea mays L.) from highland Mexico: New accelerator mass spectometry dates and the implications. Proc Natl Acad Sci USA 98, 2101–2103 (2001).
31
BD Smith, Reassessing Coxcatlan Cave and the early history of domesticated plants in Mesoamerica. Proc Natl Acad Sci USA 102, 9438–9445 (2005).
32
FE Smiley, The agricultural transition in the northern Southwest: Patterns in the current chronometric data. Kiva 60, 165–189 (1994).
33
, ed DA Gregory (Center for Desert Archaeol, Tucson, AZ Excavations in the Santa Cruz River Floodplain, 1999).
34
JB Mabry Subsistence and Resource Use Strategies of Early Agricultural Communities in Southern Arizona, ed MW Diehl (Center for Desert Archaeol, Tucson, AZ), pp. 113–152 (2005).
35
, eds EK Huber, CR Van West (Statistical Research, Tempe, AZ Fence Lake Project, 2005).
36
, eds SM Whittlesey, SJ Hesse, MS Foster (SWCA Environmental Consultants, Tucson, AZ Recurrent Sedentism and the Making of Place, 2009).
37
, ed JB Mabry (Center for Desert Archaeol, Tucson, AZ Las Capas, 2008).
38
BD Smith, Reconsidering the Ocampo Caves and the era of incipient cultivation in Mesoamerica. Lat Am Antiq 8, 342–383 (1997).
39
BD Smith, Documenting plant domestication: The consilience of biological and archaeological approaches. Proc Natl Acad Sci USA 98, 1324–1326 (2001).
40
VR Jaenicke–Després, BD Smith Histories of Maize, eds JE Staller, RH Tykot, BF Benz (Elsevier, Amsterdam), pp. 83–95 (2006).
41
E Haury Courses Toward Urban Life, eds RJ Braidwood, GR Willey (Wenner–Gren Foundation for Anthropol Res, New York), pp. 106–131 (1962).
42
BF Benz Pacific Latin America in Prehistory, ed M Blake (Washington State Univ Press, Pullman), pp. 25–38 (1999).
43
L Campbell Examining the Farming/Language Dispersal Hypothesis, eds P Bellwood, C Renfrew (McDonald Inst Archaeol Res, Cambridge, United Kingdom), pp. 49–63 (2002).
44
RS Malhi, et al., Native American mtDNA prehistory in the American Southwest. Am J Phys Anthropol 120, 108–124 (2003).
45
DL Shaul, JH Hill, Tepimans, Yumans, and other Hohokam. Am Antiq 63, 375–396 (1998).
46
DR Wilcox Ripples in the Chichimec Sea, eds FJ Mathien, RH McGuire (Southern Illinois Univ Press, Carbondale, IL), pp. 135–153 (1986).
47
JG Lorenz, DG Smith, Distribution of four founding mtDNA haplogroups among Native North Americans. Am J Phys Anthropol 101, 307–323 (1996).
48
JA Eshleman, et al., Mitochondrial DNA and prehistoric settlements: Native migrations on the western edge of North America. Hum Biol 76, 55–75 (2004).
49
FA Kaestle, DG Smith, Ancient mitochondrial DNA evidence for prehistoric population movement: The Numic expansion. Am J Phys Anthropol 115, 1–12 (2001).
50
BM Kemp, Mesoamerica and Southwest prehistory, and the entrance of humans into the Americas: Mitochondrial DNA evidence. (Univ California, Davis, CA, PhD dissertation. (2006).
51
TA Kohler, M Pier Glaude, J-P Bocquet-Appel, BM Kemp, The Neolithic demographic transition in the US Southwest. Am Antiq 73, 645–669 (2008).
52
CS Fowler, Some lexical clues to Uto-Aztecan prehistory. Int J Am Linguist 49, 224–257 (1983).
53
JH Hill, Northern Uto-Aztecan and Kiowa-Tanoan: Evidence of contact between the proto-languages? Int J Am Linguist 74, 155–188 (2008).
54
TR Van Devender, WG Spaulding, Development of vegetation and climate in the southwestern United States. Science 204, 701–710 (1979).
55
PV Wells, Paleobiogeography of montane islands in the Great Basin since the last glaciopluvial. Ecol Monogr 53, 341–382 (1983).
56
DB Madsen Anthropology of the Desert West, eds CJ Condie, DD Fowler (Univ Utah, Salt Lake City, UT) Vol 110, 21–41, University of Utah Anthropological Papers. (1986).
57
KV Flannery Guilá Naquitz (Academic, New York, 1986).
58
J Malusa, Phylogeny and biogeography of the pinyon pines (Pinus subsect. Cembroides). Syst Bot 17, 42–66 (1992).
59
C Beck, GT Jones, The terminal Pleistocene/early Holocene archaeology of the Great Basin. J World Prehist 11, 161–236 (1997).
60
RM Lanner, TR Van Devender Ecology and Biogeography of Pinus, ed DM Richardson (Cambridge Univ Press, Cambridge, United Kingdom), pp. 171–182 (1998).
61
PA Koehler, RS Anderson, WG Spaulding, Development of vegetation in the central Mojave Desert of California during the Late Quaternary. Palaeogeogr Palaeocl Palaeoecol 215, 297–311 (2005).
62
R Byrne, E Edlund, S Mensing, ed RB Standiford (US Dept Agriculture, Pacific Southwest Research Station, Berkeley, CA), pp. 182–188, General Technical Report PSW-126. (1991).
63
TR Van Devender, Holocene woodlands in the southwestern deserts. Science 198, 189–192 (1977).
64
JS Munroe, Holocene timberline and palaeoclimate of the northern Uinta Mountains, northeastern Utah, USA. The Holocene 13, 175–185 (2003).
65
PE Wigand, D Rhode Great Basin Aquatic Systems History, eds R Hershler, DB Madsen, DR Currey (Smithsonian Inst Press, Washington, DC) Vol. 33, 309–367, Smithsonian Contributions to the Earth Sciences. (2002).
66
DK Grayson The Desert's Past (Smithsonian Inst Press, Washington, DC, 1993).
67
KM Menking, RY Anderson, Contributions of La Niña and El Niño to middle Holocene drought and late Holocene moisture in the American Southwest. Geology 31, 937–940 (2003).
68
JB Mabry Paleoindian and Archaic Sites in Arizona, ed JB Mabry (Arizona State Historic Preservation Office, Phoenix, AZ), pp. 19–31 (1998).
69
C Niederberger, Early sedentary economy in the Basin of Mexico. Science 203, 131–142 (1979).
70
S Scott Archaeology of Ancient Mexico and Central America, eds ST Evans, DL Webster (Garland, New York), pp. 266–270 (2001).
71
JM Heidke Rio Nuevo Archaeology Program, 2000–2003, eds JH Thiel, JB Mabry (Center for Desert Archaeol, Tucson, AZ), pp. 7.1–7.93 (2006).
72
JE Clark, D Cheetham The Archaeology of Tribal Societies, ed WA Parkinson (Int Monogr in Prehistory, Ann Arbor, MI), pp. 278–339 (2002).
73
JE Clark, D Gosser The Emergence of Pottery, eds WK Barnett, JW Hoopes (Smithsonian Inst Press, Washington, DC), pp. 209–222 (1995).
74
JP Carpenter, G Sánchez, C ME Villalpando The Late Archaic Across the Borderlands, ed BJ Vierra (Univ Texas Press, Austin, TX), pp. 13–40 (2005).
75
RS MacNeish, A Nelken–Terner, I Weitlaner-Johnson The Prehistory of the Tehuacán Valley (Univ Texas Press, Austin, TX) Vol. 2 (1967).
76
ND Justice Stone Age Spear and Arrow Points of the Southwestern United States (Indiana Univ Press, Bloomington, IN, 2002).
77
REW Adams Prehistoric Mesoamerica (Univ Oklahoma Press, 3rd ed, Norman, OK, 2005).
78
HC Cutler, TW Whitaker, History and distribution of the cultivated cucurbits in the Americas. Am Antiq 26, 469–485 (1961).
79
WE Doolittle, JB Mabry Histories of Maize, eds JE Staller, RH Tykot, BF Benz (Elsevier, Amsterdam), pp. 109–121 (2006).
80
H Neff, et al., Early Maya adaptive patterns: Mid–late Holocene paleoenvironmental evidence from Pacific Guatemala. Lat Am Antiq 17, 287–315 (2006).
81
MD Pohl, et al., Early agriculture in the Maya lowlands. Lat Am Antiq 7, 355–372 (1996).
82
AC MacWilliams, RJ Hard, JR Roney, KR Adams, WL Merrill Archaeology Without Borders, eds LD Webster, ME McBrinn (Univ Press of Colorado, Boulder, CO), pp. 35–54 (2008).
83
LL Ely, Y Enzel, VR Baker, DR Cayan, A 5000-year record of extreme floods and climate change in the southwestern United States. Science 262, 410–412 (1993).
84
SE Metcalfe, A Bimpson, AJ Courtice, SL O'Hara, DM Taylor, Climate change at the monsoon/westerly boundary in northern Mexico. J Paleolimnol 17, 155–171 (1997).
85
IV Buckler ES, DM Pearsall, TP Holtsford, Climate, plant ecology, and central Mexican Archaic subsistence. Curr Anthropol 39, 152–164 (1998).
86
JR Ortega–Ramírez, A Valiente–Banuet, J Urrutia–Fucugauchi, CA Mortera–Gutiérrez, G Alvarado–Valdez, Paleoclimatic changes during the Late Pleistocene—Holocene in Laguna Babícora, near the Chihuahuan Desert, México. Can J Earth Sci 35, 1168–1179 (1998).
87
VJ Polyak, Y Asmerom, Late Holocene climate and cultural changes in the southwestern United States. Science 294, 148–151 (2001).
88
L Nordt, Late Quaternary fluvial landscape evolution in desert grasslands of northern Chihuahua, Mexico. Geol Soc Am Bull 115, 596–606 (2003).
89
RJ Hard, JR Roney The Late Archaic across the Borderlands, ed BJ Vierra (Univ Texas Press, Austin, TX), pp. 141–186 (2005).
90
SE Metcalfe, SL O'Hara, M Caballero, SJ Davies, Records of Late Pleistocene–Holocene climatic change in Mexico—A review. Quaternary Sci Rev 19, 699–721 (2000).
91
MR Waters, Late Quaternary lacustrine history and paloeclimatic signficance of pluvial Lake Cochise, southeastern Arizona. Quaternary Res 32, 1–11 (1989).
92
SE Metcalfe, FA Street–Perrott, RA Perrott, DD Harkness, Palaeolimnology of the Upper Lerma Basin, Mexico: A record of climatic change and anthropogenic disturbance since 11600 yr BP. J Paleolimnol 5, 197–218 (1991).
93
PR Krider, Paleoclimatic significance of late Quaternary lacutrine and alluvial stratigraphy, Animas Valley, New Mexico. Quaternary Res 50, 283–289 (1998).
94
BB Huckell, The Archaic prehistory of the North American Southwest. J World Prehist 10, 305–373 (1996).
95
JB Mabry, WE Doolittle Archaeology Without Borders, eds LD Webster, ME McBrinn (Univ Press of Colorado, Boulder, CO), pp. 55–70 (2008).
96
BJ Roth, A Freeman, The Middle Archaic Period and the transition to agriculture in the Sonoran Desert of southern Arizona. Kiva 73, 321–353 (2008).
97
MW Diehl Rediscovering Darwin, eds CM Barton, GA Clark (Am Anthropol Assoc, Arlington, VA) Vol. 7, 251–266, Am Anthropol Assoc Archaeol Papers. (1997).
98
DR Piperno, DM Pearsall The Origins of Agriculture in the Lowland Neotropics (Academic, San Diego, 1998).
99
, eds DJ Kennett, B Winterhalder (Univ California Press, Berkeley, CA Behavioral Ecology and the Transition to Agriculture, 2006).
100
BB Huckell Of Marshes and Maize (Univ Arizona Press, Tucson, AZ) Vol. 59, Univ Arizona Anthropol Papers. (1995).
101
SK Fish, PR Fish, J Madsen Perspectives on Southwestern Prehistory, eds PE Minnis, CL Redman (Westview Press, Boulder, CO), pp. 76–91 (1990).
102
WH Doleman The Late Archaic across the Borderlands, ed BJ Vierra (Univ Texas Press, Austin, TX), pp. 113–140 (2005).
103
PJ Castiglia, PJ Fawcett, Large Holocene lakes and climate change in the Chihuahuan Desert. Geology 34, 113–116 (2006).
104
MS Berry Time, Space, and Transition in Anasazi Prehistory (Univ Utah Press, Salt Lake City, UT, 1982).
105
MD Ogilvie The Late Archaic across the Borderlands, ed BJ Vierra (Univ Texas Press, Austin, TX), pp. 84–112 (2005).
106
RG Matson The Origins of Southwestern Agriculture (Univ Arizona Press, Tucson, AZ, 1991).
107
BJ Roth, Late Archaic occupation of the Upper Bajada: Excavations at AZ AA:12:84 (ASM). Kiva 61, 189–207 (1995).
108
MW Diehl, JA Waters Behavioral Ecology and the Transition to Agriculture, eds DJ Kennett, B Winterhalder (Univ California Press, Berkeley, CA), pp. 63–86 (2006).
109
DB Craig, M Hopkins, T Carpenter Summary of Archaeological Data Recovery for Pima County Regional Wastewater Reclamation Department Plant Interconnect Project, Pima County, Arizona (Northland Research, Tempe, AZ, 2009).
110
SA Herr, Las Capas. Archaeol Southwest 23, 9–11 (2009).
111
, eds JH Thiel, JB Mabry (Center for Desert Archaeol, Tucson, AZ Rio Nuevo Archaeology Program, 2000–2003, 2006).
112
WE Doolittle Canal Irrigation in Prehistoric Mexico (Univ Texas Press, Austin, TX, 1990).
113
SC Caran, JA Neely, Hydraulic engineering in prehistoric Mexico. Sci Am 295, 78–85 (2006).
114
RJ Hard, JR Roney, A massive terraced village complex in Chihuahua, Mexico, 3000 years before present. Science 279, 1661–1664 (1998).
115
RJ Hard, JE Zapata, BK Moses, JR Roney, Terrace construction in northern Chihuahua, Mexico: 1150 B.C. and modern experiments. J Field Archaeol 26, 129–146 (1999).
116
JR Roney, RJ Hard Traditions, Transitions, and Technologies, ed S Schlanger (Univ Colorado Press, Boulder, CO), pp. 163–180 (2002).
117
RJ Hard, KR Adams, JR Roney, KM Schmidt, GJ Fritz Case Studies in Environmental Archaeology, eds E Reitz, CM Scarry, SJ Scudder (Springer, New York), pp. 315–333 (2008).
118
RJ Hard, JR Roney Trincheras Sites in Time, Space, and Society, eds PR Fish, SK Fish, ME Villalpando (Univ Arizona Press, Tucson, AZ), pp. 11–52 (2007).
119
SA LeBlanc Examining the Farming/Language Dispersal Hypothesis, eds P Bellwood, C Renfrew (McDonald Inst Archaeol Res, Cambridge, United Kingdom), pp. 357–365 (2002).
120
KV Flannery, J Marcus, The origin of war: New 14C dates from ancient Mexico. Proc Natl Acad Sci USA 100, 11801–11805 (2003).
121
DE Formby, Pinto–Gypsum Complex projectile points from Arizona and New Mexico. Kiva 51, 99–127 (1986).
122
AL Phelps, An inventory of prehistoric Native American sites in northwestern Chihuahua. The Artifact 36, 1–176 (1998).
123
MR Miller, NA Kenmotsu The Prehistory of Texas, ed TK Perttula (Texas A&M Univ Press, College Station, TX), pp. 205–265 (2004).
124
BJ Vierra The Late Archaic across the Borderlands, ed BJ Vierra (University of Texas Press, Austin, TX), pp. 187–218 (2005).
125
J Heath, Uto-Aztecan morphophonemics. Int J Am Linguist 43, 27–36 (1977).
126
CS Fowler Corn and Culture in the Prehistoric New World, eds S Johannessen, CA Hastorf (Westview Press, Boulder, CO), pp. 445–467 (1994).
127
L Valiñas Coalla Nomadic and Sedentary Peoples in Northern Mexico, eds M-A Hers, JL Mirafuentes, MdlD Soto, M Vallebueno (Universidad Nacional Autónoma de México, Mexico City), pp. 175–205, (Translated from Spanish). (2000).
128
CH Brown Histories of Maize, eds JE Staller, RH Tykot, BF Benz (Elsevier, Amsterdam), pp. 647–663 (2006).
129
T Kaufman, Archaeological and linguistic correlations in Mayaland and associated areas of Meso-America. World Archaeol 8, 101–118 (1976).
Information & Authors
Information
Published in
Cover image: Pictured is a composite image of fossil marine plankton foraminifera on the floor of the Atlantic Ocean. Planktonic foraminifera, which accumulate in great abundance in some parts of the seafloor to form “calcareous ooze,” have been the subject of numerous studies on speciation in the fossil record. Pincelli M. Hull and Richard D. Norris find that the morphological similarity between closely related species and the morphometric techniques employed can greatly influence evolutionary interpretations. See the article by Hull and Norris on pages 21224–21229. Image courtesy of Pincelli M. Hull.
Classifications
Copyright
© 2009.
Submission history
Received: June 22, 2009
Published online: December 15, 2009
Published in issue: December 15, 2009
Keywords
Acknowledgments
We are grateful for the logistical support provided by the Mexico-North Research Network and the University of Texas at San Antonio and for the research conducted by Desert Archaeology, Inc. We thank the Instituto Nacional de Antropología e Historia for permission to conduct archaeological field research in Mexico. Funding for this research was provided by National Science Foundation Grants SBR-9708610, SBR-9809839, SBR-0219185, and SBR-0220292, the National Geographic Society, the National Endowment for the Humanities, the Smithsonian's National Museum of Natural History, the University of Texas at San Antonio, the Arizona Department of Transportation, and the City of Tucson.
Notes
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/cgi/content/full/0906075106/DCSupplemental.
Authors
Competing Interests
The authors declare no conflict of interest.
Metrics & Citations
Metrics
Citation statements
Altmetrics
Citations
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.
Cited by
Loading...
View Options
View options
PDF format
Download this article as a PDF file
DOWNLOAD PDFLogin options
Check if you have access through your login credentials or your institution to get full access on this article.
Personal login Institutional LoginRecommend to a librarian
Recommend PNAS to a LibrarianPurchase options
Purchase this article to access the full text.