December 30, 2014 u vol. 111 u no. 52 u 18401–18800 Cover image: Pictured are Konik horses, a semiferal breed, at a nature reserve in Oostvaar- dersplassen, Holland. Mikkel Schubert et al. sequenced the DNA from ancient horse bones and compared it to the genomes of five modern domesticated breeds and the only living wild horse species, Przewalski’s horse. Phylogenetic analysis revealed that domesticated breeds likely derived at least partially from the ancient populations. In addition, genes involved in muscle, limb, joint, and cardiac system development, and in social behavior, learning capa- bilities, fear response, and agreeableness were favored during domestication, indicating adaptations that may have resulted from human use and taming. See the article by Schubert et al. on pages E5661–E5669. Image courtesy of Ruben Smit (photographer). From the Cover E5661 Genetics of horse domestication 18460 Dating mastodon extinction 18524 Ethnic diversity and price bubbles 18530 Gulf of Mexico hypoxic zone 18709 Plague bacteria and flea hosts Contents REVIEWER ACKNOWLEDGMENT (ONLINE ONLY) E5724 Acknowledgment of Reviewers, 2014 THIS WEEK IN PNAS SCIENCE AND CULTURE—How science intersects with culture 18401 In This Issue 18403 Science and Culture: Q&A with Roger Malina Maggie McKee LETTERS (ONLINE ONLY) COMMENTARIES E5602 Incorrect representation of Barrier Canyon rock art site’s history and other factors invalidate reported dates Nancy Simon and Richard Reed 18405 The curious case of the Arctic mastodons Duane Froese E5604 Reply to Simon and Reed: Independent and converging See companion article on page 18460 results rule out historic disturbance and confirm age constraints for Barrier Canyon rock art 18407 Downsides of social capital Joel L. Pederson, Melissa S. Chapot, Steven R. Simms, Alejandro Portes Reza Sohbati, Tammy M. Rittenour, Andrew S. Murray, See companion article on page 18524 and Gary Cox 18409 Subtle genetic modifications transformed an E5605 Questionable evidence of natural warming of the enteropathogen into a flea-borne pathogen northwestern United States Elisabeth Carniel John T. Abatzoglou, David E. Rupp, and Philip W. Mote See companion article on page 18709 E5607 Reply to Abatzoglou et al.: Atmospheric controls on northwest United States air temperatures, 1948–2012 PNAS PLUS James A. Johnstone and Nathan J. Mantua 18411 Significance Statements Brief statements written by the authors about the significance of Free online through the PNAS open access option. their papers. PNAS u December 30, 2014 u vol. 111 u no. 52 u iii–viii Downloaded by guest on October 1, 2021 EARTH, ATMOSPHERIC, AND PLANETARY SCIENCES PERSPECTIVE 18460 American mastodon extirpation in the Arctic and Subarctic predates human colonization and terminal 18414 A taxonomy of prospection: Introducing an Pleistocene climate change organizational framework for future-oriented cognition Grant D. Zazula, Ross D. E. MacPhee, Jessica Z. Metcalfe, Karl K. Szpunar, R. Nathan Spreng, and Daniel L. Schacter Alberto V. Reyes, Fiona Brock, Patrick S. Druckenmiller, Pamela Groves, C. Richard Harington, Gregory W. L. Hodgins, Michael L. Kunz, Fred J. Longstaffe, Daniel H. Mann, H. Gregory McDonald, Shweta Nalawade-Chavan, INAUGURAL ARTICLES and John R. Southon See Commentary on page 18405 18422 van der Waals interactions at the nanoscale: The effects 18466 Occurrence of pristine aerosol environments on of nonlocality a polluted planet Yu Luo, Rongkuo Zhao, and John B. Pendry Douglas S. Hamilton, Lindsay A. Lee, Kirsty J. Pringle, Carly L. Reddington, Dominick V. Spracklen, 18428 Place cells in the hippocampus: Eleven maps for and Kenneth S. Carslaw eleven rooms Charlotte B. Alme, Chenglin Miao, Karel Jezek, 18472 Soil surface acidity plays a determining role in the Alessandro Treves, Edvard I. Moser, atmospheric-terrestrial exchange of nitrous acid and May-Britt Moser Melissa A. Donaldson, David L. Bish, and Jonathan D. Raff 18478 Laser altimetry reveals complex pattern of Greenland Ice Sheet dynamics Beata M. Csatho, Anton F. Schenk, Cornelis J. van der Veen, PHYSICAL SCIENCES Gregory Babonis, Kyle Duncan, Soroush Rezvanbehbahani, Michiel R. van den Broeke, Sebastian B. Simonsen, APPLIED PHYSICAL SCIENCES Sudhagar Nagarajan, and Jan H. van Angelen E5609 Absolute position total internal reflection microscopy with an optical tweezer ENGINEERING Lulu Liu, Alexander Woolf, Alejandro W. Rodriguez, 18484 Mechanical resilience and cementitious processes in and Federico Capasso Imperial Roman architectural mortar Marie D. Jackson, Eric N. Landis, Philip F. Brune, Massimo E5616 Links that speak: The global language network Vitti, Heng Chen, Qinfei Li, Martin Kunz, Hans-Rudolf and its association with global fame Wenk, Paulo J. M. Monteiro, and Anthony R. Ingraffea Shahar Ronen, Bruno Gonçalves, Kevin Z. Hu, Alessandro Vespignani, Steven Pinker, and César A. Hidalgo ENVIRONMENTAL SCIENCES E5623 Electrically pumped semiconductor laser with monolithic 18490 Life cycle air quality impacts of conventional and control of circular polarization alternative light-duty transportation in the Patrick Rauter, Jiao Lin, Patrice Genevet, Suraj P. Khanna, United States Mohammad Lachab, A. Giles Davies, Edmund H. Linfield, Christopher W. Tessum, Jason D. Hill, and Julian D. Marshall and Federico Capasso 18530 Cost-effective targeting of conservation investments to 18422 van der Waals interactions at the nanoscale: The effects reduce the northern Gulf of Mexico hypoxic zone of nonlocality Sergey S. Rabotyagov, Todd D. Campbell, Michael Yu Luo, Rongkuo Zhao, and John B. Pendry White, Jeffrey G. Arnold, Jay Atwood, M. Lee Norfleet, Catherine L. Kling, Philip W. Gassman, 18436 Existence of isostatic, maximally random jammed Adriana Valcu, Jeffrey Richardson, R. Eugene Turner, monodisperse hard-disk packings and Nancy N. Rabalais Steven Atkinson, Frank H. Stillinger, and Salvatore Torquato PHYSICS CHEMISTRY 18496 Physical basis of spindle self-organization 18442 Structural dynamics inside a functionalized Jan Brugués and Daniel Needleman metal–organic framework probed by ultrafast 18501 Electronic evidence of an insulator–superconductor 2D IR spectroscopy crossover in single-layer FeSe/SrTiO films Jun Nishida, Amr Tamimi, Honghan Fei, Sonja Pullen, 3 Junfeng He, Xu Liu, Wenhao Zhang, Lin Zhao, Defa Liu, Sascha Ott, Seth M. Cohen, and Michael D. Fayer Shaolong He, Daixiang Mou, Fangsen Li, Chenjia Tang, Zhi 18448 In vivo anticancer activity of rhomboidal Li, Lili Wang, Yingying Peng, Yan Liu, Chaoyu Chen, Li Yu, Pt(II) metallacycles Guodong Liu, Xiaoli Dong, Jun Zhang, Chuangtian Chen, Ivan V. Grishagin, J. Bryant Pollock, Swati Kushal, Zuyan Xu, Xi Chen, Xucun Ma, Qikun Xue, and X. J. Zhou Timothy R. Cook, Peter J. Stang, and Bogdan Z. Olenyuk 18596 Thermotropic liquid crystals from biomacromolecules 18454 Quantum delocalization of protons in the Kai Liu, Dong Chen, Alessio Marcozzi, Lifei Zheng, hydrogen-bond network of an enzyme active site Juanjuan Su, Diego Pesce, Wojciech Zajaczkowski, Anke Lu Wang, Stephen D. Fried, Steven G. Boxer, Kolbe, Wojciech Pisula, Klaus Müllen, Noel A. Clark, and Thomas E. Markland and Andreas Herrmann iv u www.pnas.org Downloaded by guest on October 1, 2021 STATISTICS 18513 Forests, fields, and the edge of sustainability at the 18507 Topological sensitivity analysis for systems biology ancient Maya city of Tikal Ann C. Babtie, Paul Kirk, and Michael P. H. Stumpf David L. Lentz, Nicholas P. Dunning, Vernon L. Scarborough, Kevin S. Magee, Kim M. Thompson, Eric Weaver, Christopher Carr, Richard E. Terry, Gerald Islebe, Kenneth B. Tankersley, Liwy Grazioso Sierra, SOCIAL SCIENCES John G. Jones, Palma Buttles, Fred Valdez, and Carmen E. Ramos Hernandez ANTHROPOLOGY 18513 Forests, fields, and the edge of sustainability at the ancient Maya city of Tikal BIOLOGICAL SCIENCES David L. Lentz, Nicholas P. Dunning, Vernon L. Scarborough, Kevin S. Magee, Kim M. Thompson, Eric APPLIED BIOLOGICAL SCIENCES Weaver, Christopher Carr, Richard E. Terry, Gerald Islebe, Kenneth B. Tankersley, Liwy Grazioso Sierra, E5633 Proteogenomic analysis and global discovery of John G. Jones, Palma Buttles, Fred Valdez, posttranslational modifications in prokaryotes and Carmen E. Ramos Hernandez Ming-kun Yang, Yao-hua Yang, Zhuo Chen, Jia Zhang, Yan Lin, Yan Wang, Qian Xiong, Tao Li, Feng Ge, Donald A. Bryant, and Jin-dong Zhao ECONOMIC SCIENCES 18519 Economic optimization of a global strategy to address BIOCHEMISTRY the pandemic threat Jamison Pike, Tiffany Bogich, Sarah Elwood, David C. 18542 Stable, uncleaved HIV-1 envelope glycoprotein gp140 Finnoff, and Peter Daszak forms a tightly folded trimer with a native-like structure James M. Kovacs, Erik Noeldeke, Heather Jiwon Ha, 18524 Ethnic diversity deflates price bubbles Hanqin Peng, Sophia Rits-Volloch, Stephen C. Harrison, Sheen S. Levine, Evan P. Apfelbaum, Mark and Bing Chen Bernard, Valerie L. Bartelt, Edward J. Zajac, and David Stark 18548 Outward-facing conformers of LacY stabilized See Commentary on page 18407 by nanobodies Irina Smirnova, Vladimir Kasho, Xiaoxu Jiang, Els Pardon, Jan Steyaert, and H. Ronald Kaback ENVIRONMENTAL SCIENCES 18554 A divergent Pumilio repeat protein family for pre-rRNA 18530 Cost-effective targeting of conservation investments to processing and mRNA localization reduce the northern Gulf of Mexico hypoxic zone Chen Qiu, Kathleen L. McCann, Robert N. Wine, Susan J. Sergey S. Rabotyagov, Todd D. Campbell, Michael Baserga, and Traci M. Tanaka Hall White, Jeffrey G. Arnold, Jay Atwood, M. Lee Norfleet,