DOCSLIB.ORG

Genetic Diversity and Population Structure of Teosinte

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Genetic Diversity and Population Structure of Teosinte Copyright © 2005 by the Genetics Society of America DOI: 10.1534/genetics.104.031393 Genetic Diversity and Population Structure of Teosinte Kenji Fukunaga,*,1 Jason Hill,† Yves Vigouroux,*,2 Yoshihiro Matsuoka,*,3 Jesus Sanchez G.,‡ Kejun Liu,§,4 Edward S. Buckler** and John Doebley*,5 *Laboratory of Genetics, University of Wisconsin, Madison, Wisconsin 53706, †Department of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108, ‡Centro Universitario de Ciencias Biologicas y Agropecuarias, Universidad de Guadalajara, Zapopan, Jalisco, Mexico CP45110, §Statistics Department, North Carolina State University, Raleigh, North Carolina 27695 and **USDA-ARS, Institute for Genomic Diversity, Cornell University, Ithaca, New York 14853 Manuscript received May 19, 2004 Accepted for publication January 3, 2005 ABSTRACT The teosintes, the closest wild relatives of maize, are important resources for the study of maize genetics and evolution and for plant breeding. We genotyped 237 individual teosinte plants for 93 microsatellites. Phylogenetic relationships among species and subspecific taxa were largely consistent with prior analyses for other types of molecular markers. Plants of all species formed monophyletic clades, although relationships among species were not fully resolved. Phylogenetic analysis indicated that the Mexican annual teosintes divide into two clusters that largely correspond to the previously defined subspecies, Z. mays ssp. parviglumis and ssp. mexicana, although there are a few samples that represent either evolutionary intermediates or hybrids between these two subspecies. The Mexican annual teosintes show genetic substructuring along geographic lines. Hybridization or introgression between some teosintes and maize occurs at a low level and appears most common with Z. mays ssp. mexicana. Phylogeographic and phylogenetic analyses of the Mexican annual teosintes indicated that ssp. parviglumis diversified in the eastern part of its distribution and spread from east to west and that ssp. mexicana diversified in the Central Plateau of Mexico and spread along multiple paths to the north and east. We defined core sets of collections of Z. mays ssp. mexicana and ssp. parviglumis that attempt to capture the maximum number of microsatellite alleles for given sample sizes. EOSINTE is a wild grass native to Mexico and Cen- analyses, a refined understanding of its phylogenetics Ttral America (Figure 1) and the closest wild relative and population structure can help guide further re- of cultivated maize (Zea mays ssp. mays L.). Teosinte search in all of these areas. represents an important resource for the study of maize Together, teosinte and maize compose the genus Zea, genetics (Evans and Kermicle 2001), quantitative ge- which has four species (Figure 1): (1) Z. luxurians netics (Lukens and Doebley 1999), molecular popula- (Durieu and Ascherson) Bird, an annual teosinte from tion genetics (Gaut et al. 2000), genome evolution Central America; (2) Z. diploperennis Iltis, Doebley and (Sanz-Alferez et al. 2003), and crop evolution (Doe- Guzman, a diploid perennial teosinte from Jalisco, Mex- bley 1990a). Notably, teosinte has become one of the ico; (3) Z. perennis (Hitchc.) Reeves and Mangels- best-characterized systems for plant molecular popula- dorf, a tetraploid perennial teosinte from Jalisco, Mex- tion genetics, including studies utilizing DNA samples ico; and (4) Z. mays, a polytypic annual species that recovered from archeological specimens (Jaenicke- includes four subspecies. The four subspecies are (1) Despre´s et al. 2003). The teosintes also represent an ssp. mays (maize); (2) ssp. mexicana (Schrader) Iltis, important potential resource for maize breeding, al- a large-spikeleted teosinte adapted to the drier high m) of northern and central 2700–1600ف) though they have not yet been extensively used in this elevations capacity. Given the breadth of use of teosinte in genetic Mexico; (3) ssp. parviglumis Iltis and Doebley, a small- spikeleted teosinte adapted to the moister middle eleva- (m) of southwestern Mexico; and (4 1800–400ف) tion ssp. huehuetenangensis (Iltis and Doebley) Doebley, an 1Present address: The International Research Center for Japanese Studies, 3-2 Oeyama-cho, Goryo, Nishikyo-ku, Kyoto 610-1192, Japan. annual teosinte found only in the province of 2Present address: Institut de Recherche pour le Developpement, Mont- Huehuetenango in western Guatemala (Doebley pellier 34730, France. 1990b). The four species of Z. mays have been placed 3Present address: Fukui Prefectural University, Matsuoka-cho, Yos- into two sections: section Zea, which contains only Z. hida-gun, Fukui 910-1195, Japan. mays, and section Luxuriantes, which is composed of the 4Present address: National Institute of Statistical Sciences, 19 T. W. Alexander Dr., Research Triangle Park, NC 27709-4006. other three species. Most of these teosinte species and 5Corresponding author: Laboratory of Genetics, University of Wiscon- subspecies have narrow geographic distributions con- sin, 445 Henry Mall, Madison, WI 53706. E-mail: [email protected] sisting of only a few local populations; however, ssp. Genetics 169: 2241–2254 (April 2005) 2242 K. Fukunaga et al. Figure 1.—Geographical distribution of the teosinte populations used in this study. Since many accessions come from geographi- cally very close locations, their symbols overlap on the map. mexicana and ssp. parviglumis are exceptions, being 1). Wilkes (1967) divided Z. mays ssp. mexicana into three widely distributed in Mexico (Figure 1). Recently, Iltis races: Central Plateau, Chalco, and Nobogame. Because many new populations have been discovered since Wilkes’ seminal and Benz (2000) classified Z. luxurians from Nicaragua work (Sanchez et al. 1998), we divided Z. mays ssp. mexicana as a new species, Z. nicaraguensis Iltis and Benz. Here, into five geographical groups: Central Plateau, Chalco, Du- we treat it as one geographical group of Z. luxurians. rango, Nobogame, and Puebla. Further extending Wilkes’ To clarify the phylogeny and population structure of analysis, we divided Z. mays ssp. parviglumis into two races, the teosintes, we used a set of 93 microsatellite or simple Balsas and Jalisco, and into five geographical groups, eastern Balsas, Central Balsas, Jalisco, Oaxaca, and southern Guerrero sequence repeat (SSR) loci and a sample of 237 individ- (Table 1, Figure 1). Two individual plants of the genus Tripsa- ual teosinte plants that cover the entire geographical cum (one individual each of T. zopilotense and T. peruvianum) distribution of the teosintes. We addressed four ques- were used as the outgroup in phylogenetic analyses. See sup- tions: (1) How are Zea taxa related to each other?, (2) plementary materials at http://genetics.org/supplemental/ How did the annual teosintes diversify in Mexico?, (3) for the complete passport data for the plants, including germ- How is genetic diversity structured in the Mexican an- plasm bank accession numbers and geographical coordinates. SSR genotypes: Ninety-three SSRs that are evenly distributed nual teosintes?, and (4) Has introgression among spe- throughout the genome were used to genotype all 237 Zea cies or subspecies played a role in teosinte evolution? plants and the two Tripsacum individuals. These SSRs were We also define core sets of teosinte accessions that best used in the previous analysis of maize and its wild progenitor capture the diversity of the teosintes. (Matsuoka et al. 2002b). The plants were genotyped at Celera AgGen (Davis, CA) following procedures published elsewhere (Matsuoka et al. 2002b). See supplementary materials at MATERIALS AND METHODS http://www.genetics.org/supplemental/ for a list of the SSRs, their repeat type, and their genomic locations. Plant materials: We sampled 237 teosinte plants from 172 Diversity analyses: Basic statistics, including the number of accessions representing the entire geographical distribution alleles, observed heterozygosity, gene diversity (or expected of teosinte from northern Mexico to western Nicaragua. For each heterozygosity), and the number of taxon-specific (private) accession, 1–5 individuals were assayed. The sample includes 93 alleles, were calculated for species, subspecies, and races using Z. mays ssp. mexicana individuals (69 accessions), 114 Z. mays ssp. PowerMarker (Liu 2002). In these analyses, individual plants parviglumis (82 accessions), 7 Z. mays ssp. huehuetenangensis (3 of possible hybrid origin as determined by population struc- accessions), 13 Z. luxurians (10 accessions), 6 Z. diploperennis ture analysis (see below) were excluded. (5 accessions), and 4 Z. perennis (3 accessions) (Figure 1, Table Phylogenetic trees: We used the FITCH program in the Genetic Diversity in Teosinte 2243 PHYLIP package (Felsenstein 1993) with the log-trans- vidual from each OTU as a representative. Individual plants of formed proportion-of-shared-alleles distance as implemented possible hybrid origin as determined by population structure in the computer program Microsat (http://hpgl.stanford.edu/ analysis (see below) were excluded. We calculated the log-trans- projects/microsat/). In FITCH, the J option was used to ran- formed proportion-of-shared-alleles distance among these in- domize the input order of samples. We constructed three dividuals and used this distance matrix in all tests. We then types of trees: (1) a tree with all individual plants, (2) a tree calculated correlation coefficients between the genetic dis- with individual plants pooled into operational taxonomic
Load more

Recommended publications
  • Resúmenes Ejecutivos Ejercicio Fiscal 2011
    Resúmenes Ejecutivos Ejercicio Fiscal 2011 Sistema Nacional de Recursos Fitogenéticos para la Alimentación y la Agricultura Resúmenes Ejecutivos Ejercicio Fiscal 2011 Servicio Nacional de Inspección y Certificación de Semillas Sistema Nacional de Recursos Fitogenéticos para la Alimentación y la Agricultura Resúmenes Ejecutivos Ejercicio Fiscal 2011 Portada y formación: Alfonso Martínez Acosta Primera edición: septiembre del 2014 D. R. © Servicio Nacional de Inspección y Certificación de Semillas Av. Presidente Juárez, núm. 13. Col. El Cortijo. CP 54000. Tlalnepantla, Estado de México. «Este programa es de carácter público, no es patrocinado ni promovido por partido político alguno y sus recursos provienen de los impuestos que pa- gan los contribuyentes. Está prohibido el uso de este programa con fines políticos, electorales, de lucro y otros distintos a los establecidos. Quien haga uso indebido de los recursos de este programa deberá ser denunciado y sancionado de acuerdo a la ley aplicable y ante la autoridad competente». Directorio Secretaría de Agricultura, Ganadería, Lic. Enrique Martínez y Martínez Desarrollo Rural, Pesca y Alimentación Secretario Lic. Jesús Alberto Aguilar Padilla Subsecretario de Agricultura Ing. Belisario Domínguez Méndez Director General de Productividad y Desarrollo Tecnológico Servicio Nacional de Inspección y Ing. Enriqueta Molina Macías Certificación de Semillas Dirección General del SNICS M. en C. Rosalinda González Santos Dirección de Recursos Fitogenéticos Comité Editorial SINAREFI Ing. Enriqueta Molina
    [Show full text]
  • Popped Secret: the Mysterious Origin of Corn Film Guide Educator Materials
    Popped Secret: The Mysterious Origin of Corn Film Guide Educator Materials OVERVIEW In the HHMI film Popped Secret: The Mysterious Origin of Corn, evolutionary biologist Dr. Neil Losin embarks on a quest to discover the origin of maize (or corn). While the wild varieties of common crops, such as apples and wheat, looked much like the cultivated species, there are no wild plants that closely resemble maize. As the film unfolds, we learn how geneticists and archaeologists have come together to unravel the mysteries of how and where maize was domesticated nearly 9,000 years ago. KEY CONCEPTS A. Humans have transformed wild plants into useful crops by artificially selecting and propagating individuals with the most desirable traits or characteristics—such as size, color, or sweetness—over generations. B. Evidence of early maize domestication comes from many disciplines including evolutionary biology, genetics, and archaeology. C. The analysis of shared characteristics among different species, including extinct ones, enables scientists to determine evolutionary relationships. D. In general, the more closely related two groups of organisms are, the more similar their DNA sequences will be. Scientists can estimate how long ago two populations of organisms diverged by comparing their genomes. E. When the number of genes is relatively small, mathematical models based on Mendelian genetics can help scientists estimate how many genes are involved in the differences in traits between species. F. Regulatory genes code for proteins, such as transcription factors, that in turn control the expression of several—even hundreds—of other genes. As a result, changes in just a few regulatory genes can have a dramatic effect on traits.
    [Show full text]
  • Adjustments Between Historical Flow and Sediments in a River Basin Using Genetics Algoriths
    2nd Joint Federal Interagency Conference, Las Vegas, NV, June 27 - July 1, 2010 ADJUSTMENTS BETWEEN HISTORICAL FLOW AND SEDIMENTS IN A RIVER BASIN USING GENETICS ALGORITHS Preciado, J. M, Instituto Mexicano de Tecnología del Agua, Jiutepec, Mor., [email protected],; Arganis, J. M. L., Instituto de Ingeniería, Universidad Nacional Autónoma de México, and PUMAGUA, Universidad Nacional Autónoma de México, [email protected]; Ocón G.A., Instituto Mexicano de Tecnología del Agua, Jiutepec, Mor., [email protected]; Val, S. R., PUMAGUA, Universidad Nacional Autónoma de México, [email protected]. INTRODUCTION Abstract Suspended materials in rivers are closely related to currents as well as to sediments transported by surface flows during storm periods (Ogardi, 1978). Sediments transported by the channels also come from other erosive processes in the drainage network of the river basins. Thus suspended sediment in channels results from erosion within the channel and on adjacent slopes. In Mexico, the principal federal office in charge of the hydrometric stations ceased collecting measurements of sediments. Thus genetic algorithms are very important to sediment modeling. This paper presents preliminary results of investigations using the data of the hydrometric stations of the river basin of the Apatlaco River. Correlations between annual and monthly data to were sought, in order to investigate the viability of applying techniques of evolutionary calculation to obtain models of adjustment between flow and sediments. SITE OF STUDY The Apatlaco River basin is located in the northwest portion of the state of Morelos, bounded on the north by the Federal District, to the north and the northwest by the State of Mexico, to the west by the Tembembe River basin, and to the east and the south by the Yautepec River.
    [Show full text]
  • The Aztlán Fault System: Control on the Emplacement of the Chichinautzin Range Volcanism, Southern Mexico Basin, Mexico. Seismic and Gravity Characterization
    The Aztlán Fault System: Seismic and gravity characterization 315 Boletín de la Sociedad Geológica Mexicana Volumen 67, núm. 2, 2015, p. 315-335 D GEOL DA Ó E G I I C C O A S 1904 M 2004 . C EX . ICANA A C i e n A ñ o s The Aztlán Fault System: control on the emplacement of the Chichinautzin Range volcanism, southern Mexico Basin, Mexico. Seismic and gravity characterization José Oscar Campos-Enríquez1,*, Javier Francisco Lermo-Samaniego2, Yanet Teresa Antayhua-Vera3, Marcos Chavacán3, Victor-Manuel Ramón-Márquez3,4 1 Instituto de Geofísica, Universidad Nacional Autónoma de México, México, D.F., México. 2 Instituto de Ingeniería, Universidad Nacional Autónoma de México, México, D.F., México. 3 Programa de Posgrado de Ciencias de la Tierra, Universidad Nacional Autónoma de México, D.F., Mexico. 4 Facultad de Ingeniería, Benemérita Universidad Autónoma de Puebla, Puebla, México. * [email protected] Abstract Gravity and seismic studies enabled us to establish the major features of the shallow crustal structure beneath Chichinautzin Range. Accordingly, the Chichinautzin Range evolved above Mesozoic calcareous rocks lying on a metamorphic basement. To the north and south this basement is downfaulted. Nevertheless the north dipping faults downward displace the basement to larger depths (2 to 3 km) in the Mexico and Toluca basins. In the Morelos Basin, the basin is shallower. As block-faulting evolved, the basement edge migrated southwards, thus widening an E-W oriented major depression south of the Mexico Basin. In particular, gravity modeling enabled us to integrate the different faults mapped up to today in and around the Chichinautzin Range into a fault system that can be correlated from the Nevado de Toluca.
    [Show full text]
  • Nahuatl Cultural Encyclopedia: Botany and Zoology, Balsas River, Guerrero
    FAMSI © 2007: Jonathan D. Amith Nahuatl Cultural Encyclopedia: Botany and Zoology, Balsas River, Guerrero Research Year : 2004 Culture : Nahuatl Chronology : Colonial Location : Guerrero, México Site : Balsas River Valley Table of Contents Introduction Biological Inventory Textual Documentation: Audio and Transcription Collaborations Granting Agencies Scientific Institutions and Individual Academic Researchers Indigenous Communities, Associations, and Individuals Community Outreach Appendices List of Figures Sources Cited Submitted 03/07/2007 by: Jonathan D. Amith Director: México-North Program on Indigenous Languages Research Affiliate: Gettysburg College, Department of Sociology and Anthropology; Yale University; University of Chicago [email protected] Introduction Although extensive documentation of Aztec natural history was produced in the colonial period (e.g., de la Cruz, 1940; Hernández, 1959; Sahagún, 1963) there has been virtually no comprehensive research on modern Nahuatl ethnobiology. Attempts (dating to the nineteenth century) to identify in scientific nomenclature the plants described in the aforementioned colonial sources have relied on library studies, not fieldwork. There exists no comprehensive study of modern Nahuatl ethnozoology to shed light on the prehispanic culture in this domain. This situation can be compared to Mayan studies, which has been pioneering and intensive and has contributed greatly to our understanding of this culture, both before and after conquest (see Alcorn, 1984, Berlin and Berlin, 1996; Berlin, Breedlove, and Raven, 1974; Breedlove and Laughlin, 1993; Hunn, 1977; Orellana, 1987; Roys, 1931; to name but the most well known). The present FAMSI award was to begin to fill this lagunae in primary data and, in addition, for the production of an electronic and written corpus of Nahuatl language materials on the natural history (botany and zoology) of the Balsas River Valley in central México.
    [Show full text]
  • The Growing Corn Economies of Mexico and the United States, Was Reposted to Change Its Report Number from OCS 19F-02 to FDS 19F-01
    A Report from the Economic Research Service United States Department www.ers.usda.gov of Agriculture The Growing Corn Economies of FDS-19F-01 Mexico and the United States August 2019 Steven Zahniser, Nicolás Fernando López López, Mesbah Motamed, Zully Yazmin Silva Vargas, and Tom Capehart Abstract Mexico is the largest foreign market for U.S. corn in terms of export volume and value. The North American Free Trade Agreement (NAFTA), implemented in 1994, facilitated closer integration of the U.S. and Mexican corn markets, as evidenced by rising exports to Mexico and the co-movement of U.S. and Mexican prices. Since the start of 2008, U.S. corn exports Approved by USDA’s to Mexico have been free of tariff and quota restrictions due to one of NAFTA’s provisions. World Agricultural Outlook Board The recently signed United States-Mexico-Canada Agreement (USMCA) would continue tariff- and quota-free trade in corn. In the United States and Mexico, corn production has risen, due partly to higher yields. USDA’s long-term agricultural projections suggest that in the coming decade, consumption of Mexican and U.S. grown corn will continue to increase due to expanding livestock production in both countries, even though U.S. production of corn- based ethanol is projected to decline. In terms of policy, Mexico has new support programs for small- and medium-scale producers, while the 2018 U.S. Farm Act largely maintains the income support and risk management programs that appeared in previous legislation. Keywords: Corn, United States, Mexico, trade, domestic supports, NAFTA, USMCA.
    [Show full text]
  • Shame and Linguistic Insecurity in Upper Balsas Classrooms
    University of Wisconsin Milwaukee UWM Digital Commons Theses and Dissertations December 2019 Pena, Pinahua, and Prestige: Shame and Linguistic Insecurity in Upper Balsas Classrooms Heather Gabrielle Thomas Flores University of Wisconsin-Milwaukee Follow this and additional works at: https://dc.uwm.edu/etd Part of the Social and Cultural Anthropology Commons Recommended Citation Thomas Flores, Heather Gabrielle, "Pena, Pinahua, and Prestige: Shame and Linguistic Insecurity in Upper Balsas Classrooms" (2019). Theses and Dissertations. 2337. https://dc.uwm.edu/etd/2337 This Thesis is brought to you for free and open access by UWM Digital Commons. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of UWM Digital Commons. For more information, please contact [email protected]. PENA, PINAHUA, AND PRESTIGE: SHAME AND LINGUISTIC INSECURITY IN UPPER BALSAS CLASSROOMS by Heather Thomas Flores A Thesis SubmitteD in Partial FulFillment oF the Requirements For the Degree oF Master oF Science in Anthropology at The University oF Wisconsin-Milwaukee December 2019 ABSTRACT PENA, PINAHUA, AND PRESTIGE SHAME AND LINGUISTIC INSECURITY IN UPPER BALSAS CLASSROOMS by Heather Thomas Flores The University oF Wisconsin-Milwaukee, 2019 UnDer the Supervision oF ProFessor BernarD C. Perley, PhD. This ethnography is a topical analysis oF the InDigenous EDucation system in rural Guerrero, Mexico. The purpose oF this research is to Draw out the correlations between coercive monolingual ‘Spanish only’ language policies implementeD During the mid 20th century anD the systematic Disintegration oF the Nahuatl language within what were once monolingual Nahua communities in the Upper Balsas valley. The Data presenteD in this paper is FrameD anD analyzeD through language iDeologies Discourse.
    [Show full text]
  • The Earliest Archaeological Maize (Zea Mays L.) from Highland Mexico: New Accelerator Mass Spectrometry Dates and Their Implications
    The earliest archaeological maize (Zea mays L.) from highland Mexico: New accelerator mass spectrometry dates and their implications D. R. Piperno*† and K. V. Flannery‡ *Smithsonian Tropical Research Institute, Box 2072, Balboa, Panama; and ‡Museum of Anthropology, University of Michigan, 1109 Geddes Avenue, Ann Arbor, MI 48109-1079 Contributed by K. V. Flannery, November 21, 2000 Accelerator mass spectrometry age determinations of maize cobs (Zea mays L.) from Guila´ Naquitz Cave in Oaxaca, Mexico, produced dates of 5,400 carbon-14 years before the present (about 6,250 calendar years ago), making those cobs the oldest in the Americas. Macrofossils and phytoliths characteristic of wild and domesti- cated Zea fruits are absent from older strata from the site, although Zea pollen has previously been identified from those levels. These results, together with the modern geographical distribution of wild Zea mays, suggest that the cultural practices that led to Zea domestication probably occurred elsewhere in Mexico. Guila´ Na- quitz Cave has now yielded the earliest macrofossil evidence for the domestication of two major American crop plants, squash (Cucurbita pepo) and maize. aize (Zea mays L.) is the New World’s preeminent grain Mcrop, was widely grown at the time of the European contact in both hemispheres, and was a staple food of many Fig. 1. Map of Mexico showing the location of Guila´ Naquitz Cave and the prehistoric societies. Despite decades of research by botanists, Tehuaca´ n Valley, together with the modern distribution of the populations of molecular biologists, and archaeologists, the origin and early Zea mays ssp. parviglumis from the Central Balsas River Valley, the molecular history of maize remain controversial (1–5).
    [Show full text]
  • Mechanisms for Severe Drought Occurrence in the Balsas River Basin (Mexico)
    atmosphere Article Mechanisms for Severe Drought Occurrence in the Balsas River Basin (Mexico) Ana E. Melgarejo 1, Paulina Ordoñez 2,*, Raquel Nieto 3 , Cristina Peña-Ortiz 4, Ricardo García-Herrera 5,6 and Luis Gimeno 3 1 Posgrado en Ciencias de la Tierra, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico; [email protected] 2 Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico 3 Environmental Physics Laboratory (EPhysLab), CIM–UVigo, Universidade de Vigo, 32004 Ourense, Spain; [email protected] (R.N.); [email protected] (L.G.) 4 Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, 41013 Sevilla, Spain; [email protected] 5 Departamento de Ciencias de la Tierra y Astrofísica, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid, Spain; rgarciah@fis.ucm.es 6 Instituto de Geociencias (CSIC-UCM), 28040 Madrid, Spain * Correspondence: [email protected] Abstract: This work provides an assessment of the two most intense seasonal droughts that occurred over the Balsas River Basin (BRB) in the period 1980–2017. The detection of the drought events was performed using the 6 month scale standardized precipitation–evapotranspiration index (SPEI-6) and the 6 month standardized precipitation index (SPI-6) in October. Both indices were quite similar during the studied period, highlighting the larger contribution of precipitation deficits vs. temperature excess to the drought occurrence in the basin. The origin of the atmospheric water Citation: Melgarejo, A.E.; Ordoñez, P.; Nieto, R.; Peña-Ortiz, C.; García- arriving to the BRB (1 May 1980–31 October 2017) was investigated by using a Lagrangian diagnosis Herrera, R.; Gimeno, L.
    [Show full text]
  • The Cultural and Chronological Context of Early Holocene Maize and Squash Domestication in the Central Balsas River Valley, Mexico
    The cultural and chronological context of early Holocene maize and squash domestication in the Central Balsas River Valley, Mexico Anthony J. Ranerea,b,1, Dolores R. Pipernob,c, Irene Holstb, Ruth Dickaua, and Jose´ Iriarted aDepartment of Anthropology, Temple University, Philadelphia, PA 19122; bSmithsonian Tropical Research Institute, Apartado Postal 0843-03092, Balboa, Republic of Panama; cArchaeobiology Program, Department of Anthropology, National Museum of Natural History, Washington, DC 20560; and dDepartment of Archaeology, School of Geography, Archaeology, and Earth Resources, University of Exeter, Exeter EX4 4QJ, United Kingdom Edited by Jeremy A. Sabloff, University of Pennsylvania Museum of Archaeology and Anthropology, Philadelphia, PA, and approved January 23, 2009 (received for review December 10, 2008) Molecular evidence indicates that the wild ancestor of maize is presently native to the seasonally dry tropical forest of the Central Balsas watershed in southwestern Mexico. We report here on archaeological investigations in a region of the Central Balsas located near the Iguala Valley in Guerrero state that show for the first time a long sequence of human occupation and plant exploi- tation reaching back to the early Holocene. One of the sites excavated, the Xihuatoxtla Shelter, contains well-stratified depos- its and a stone tool assemblage of bifacially flaked points, simple flake tools, and numerous handstones and milling stone bases radiocarbon dated to at least 8700 calendrical years B.P. As re- ported in a companion paper (Piperno DR, et al., in this issue of PNAS), starch grain and phytolith residues from the ground and chipped stone tools, plus phytoliths from directly associated sed- iments, provide evidence for maize (Zea mays L.) and domesticated squash (Cucurbita spp.) in contexts contemporaneous with and Fig.
    [Show full text]
  • Pollination Biology of Two Winter-Blooming Giant Columnar Cacti in the Tehuac´An Valley, Central Mexico
    Journal of Arid Environments (1997) 37: 331–341 Pollination biology of two winter-blooming giant columnar cacti in the Tehuac´an Valley, central Mexico Alfonso Valiente-Banuet*, Alberto Rojas-Mart´ınez*, Alejandro Casas†, Mar´ıa del Coro Arizmendi* & Patricia D´avila‡ *Centro de Ecolog´ıa, Universidad Nacional Aut´onoma de M´exico, Apartado Postal 70-275, M´exico 04510, D.F., M´exico †Jardin Bot´anico, Instituto de Biolog´ıa, Universidad Nacional Aut´onoma de M´exico, Apartado Postal 70-614, M´exico 04510, D.F., M´exico ‡Instituto de Biolog´ıa, Universidad Nacional Aut´onoma de M´exico, Apartado Postal 70-233, M´exico 04510, D.F., M´exico (Received 31 October 1996, accepted 25 February 1997) In the neotropics, central Mexico and Venezuela, columnar cacti (mostly belonging to tribe Pachycereae) are pollinated mainly by bats. In the Tehuac´an Valley 36 species of columnar cacti have their blooming peak almost simultaneously between April and June, and species with chiropter- ophilous pollination have been shown to be self-incompatible, fruiting only after bat pollination. Nectarivorous bats are abundant also during spring and summer, and migrate during autumn and winter. Two columnar cacti, Pachycereus weberi (tribe Pachycereae) and Pilosocereus chrysacanthus (tribe Cereae), flower during winter and early spring facing an apparent scarcity of bats. We hypothesized that under this condition, these plants may resemble the columnar cacti in extratropical deserts where both bats and diurnal vectors can effect seed production. However, we found that these two plant species have white, long tubular flowers, are nocturnal, self-incompatible and produce fruits only after the visitation of four nectar-feeding bats and two frugivorous bats.
    [Show full text]
  • Orbital Pacing and Ocean Circulation-Induced Collapses of the Mesoamerican Monsoon Over the Past 22,000 Y
    Orbital pacing and ocean circulation-induced collapses of the Mesoamerican monsoon over the past 22,000 y Matthew S. Lachnieta,1, Yemane Asmeromb, Juan Pablo Bernalc, Victor J. Polyakb, and Lorenzo Vazquez-Selemd aDepartment of Geoscience, University of Nevada, Las Vegas, NV 89154; bDepartment of Earth and Planetary Science, University of New Mexico, Albuquerque, NM 87131; cCentro de Geociencias, Universidad Nacional Autónoma de México, Querétaro 76230, Mexico; and dInstituto de Geografía, Universidad Nacional Autónoma de México, Coyoacán, Mexico City 04510, Mexico Edited by James P. Kennett, University of California, Santa Barbara, CA, and approved April 19, 2013 (received for review January 2, 2013) The dominant controls on global paleomonsoon strength include circulation was disrupted by freshwater forcing into the North summer insolation driven by precession cycles, ocean circulation Atlantic, whereas the SASM intensity strengthened during sta- through its influence on atmospheric circulation, and sea-surface dials, suggesting a hemispheric antiphasing in tropical rainfall temperatures. However, few records from the summer North linked to migrations in the latitude of the ITCZ. However, the American Monsoon system are available to test for a synchronous relative orbital and ocean circulation influence on the Meso- response with other global monsoons to shared forcings. In parti- american monsoon is unconstrained, limiting our ability to test cular, the monsoon response to widespread atmospheric reorgani- hypotheses of monsoon forcing (3), the peopling of the Americas zations associated with disruptions of the Atlantic Meridional (9), the Holocene domestication of maize and squash in Mexico Overturning Circulation (AMOC) during the deglacial period (10), climate’sinfluence on past civilizations (11), and to forecast remains unconstrained.
    [Show full text]