Project baseline: An unprecedented resource to study plant evolution across space and time

AJB Advance Article published on January 15, 2016, as 10.3732/ajb.1500313. The latest version is at http://www.amjbot.org/cgi/doi/10.3732/ajb.1500313 RESEARCH ARTICLE A M E R I C A N J O U R N A L O F B O TA N Y I N V I T E D PA P E R For the Special Issue: Evolutionary Insights from Studies of Geographic Variation Project Baseline: An unprecedented resource to study plant evolution across space and time 1 Julie R. Etterson 2,8 , Steven J. Franks 3 , Susan J. Mazer 4 , Ruth G. Shaw 5 , Nicole L. Soper Gorden 2,7 , Heather E. Schneider 4 , Jennifer J. Weber 3 , Katharine J. Winkler 2 , and Arthur E. Weis 6 PREMISE OF THE STUDY: Project Baseline is a seed bank that off ers an unprecedented opportunity to examine spatial and temporal dimensions of micro- evolution during an era of rapid environmental change. Over the upcoming 50 years, biologists will withdraw genetically representative samples of past populations from this time capsule of seeds and grow them contemporaneously with modern samples to detect any phenotypic and molecular evolution that has occurred during the intervening time. METHODS: We carefully developed this living genome bank using protocols to enhance its experimental value by collecting from multiple populations and species across a broad geographical range in sites that are likely to be preserved into the future. Seeds are accessioned with site and population data and are stored by maternal line under conditions that maximize seed longevity. This open-access resource will be available to researchers at regular intervals to evaluate contemporary evolution. KEY RESULTS: To date, the Project Baseline collection includes 100–200 maternal lines of each of 61 species collected from over 831 populations on sites that are likely to be preserved into the future across the United States (~78,000 maternal lines). Our strategically designed collection circumvents some problems that can cloud the results of “resurrection” studies involving naturally preserved or existing seed collections that are available fortuitously. CONCLUSIONS: The resurrection approach can be coupled with long-established and newer techniques over the next fi ve decades to elucidate genetic change and thereby vastly improve our understanding of temporal and spatial changes in phenotype and the evolutionary processes underlying it. KEY WORDS climate change; geographic variation; natural selection; phenotypic evolution; population diff erentiation; resurrection ecology; seed bank; species range Th e process of evolution is central to biology, and understanding how it operates in natural populations continues to be a major goal. Originally thought to proceed extremely slowly ( Darwin, 1859 ), Manuscript received 2 July 2015; revision accepted 7 October 2015. Department of Biology, University of Minnesota Duluth, 207A Swenson Science Building, 1035 Kirby Drive, Duluth, Minnesota 55812 USA; Department of Biological Sciences, 441 East Fordham Road, Fordham University, Bronx, New York 10458 USA; Department of Ecology, Evolution & Marine Biology, University of California, Santa Barbara, Santa Barbara, California 93106 USA; Department of Ecology, Evolution and Behavior, 1479 Gortner Avenue, University of Minnesota Twin Cities, St. Paul, Minnesota 55108 USA; and Department of Ecology and Evolutionary Biology, and Koffl er Scientifi c Reserve at Jokers Hill, 25 Willcocks Street, University of Toronto, Toronto, Ontario, Canada M5S 3B2 Present address: Department of Natural Sciences, Mars Hill University, 100 Athletic St, Campus Box 6671, Mars Hill, North Carolina 28754 USA Author for correspondence (e-mail: jetterso@d.umn.edu ) doi:10.3732/ajb.1500313 evolutionary changes occurring over the scale of a century were identifi ed considerably later (e.g., Antonovics and Bradshaw, 1970 ), and there is now abundant evidence that contemporary evolution is oft en much more rapid than previously assumed (reviewed by Koch et al., 2014 ). Anthropogenic disturbance to natural habitats, including climate change, continues to be a potent driver of evolu- tion. Because selection varies temporally and spatially and popula- tions have unique histories and genetic compositions, the rate and extent of evolutionary response are expected to vary across species’ ranges. Th us, anthropogenic disturbance off ers opportunities for studies of diverse evolutionary responses in wild species across both time and space. Evolutionary change can be studied directly using both temporal and spatial comparisons ( Antonovics, 1976 ; Franks et al., 2014 ). Despite these recognized approaches, investigation of evolution jointly over both large spatial extent and decadal temporal scales is hindered by inaccessibility of suitable biological material. This A M E R I C A N J O U R N A L O F B OTA N Y 103 ( 1 ): 1 – 10 , 2016 ; http://www.amjbot.org/ © 2016 Botanical Society of America • 1 Copyright 2016 by the Botanical Society of America