ALBERT

Description: Mammals diversified by colonizing drastically different environments, with each transition yielding numerous molecular changes, including losses of protein function. Though not initially deleterious, these losses could subsequently carry deleterious pleiotropic consequences. We have used phylogenetic methods to identify convergent functional losses across independent marine mammal lineages. In one extreme case, Paraoxonase 1 ( PON1 ) accrued lesions in all marine lineages, while remaining intact in all terrestrial mammals. These lesions coincide with PON1 enzymatic activity loss in marine species’ blood plasma. This convergent loss is likely explained by parallel shifts in marine ancestors’ lipid metabolism and/or bloodstream oxidative environment affecting PON1’s role in fatty acid oxidation. PON1 loss also eliminates marine mammals’ main defense against neurotoxicity from specific man-made organophosphorus compounds, implying potential risks in modern environments.

Description: The turbulent surfaces of rivers and streams are natural hotspots of biogeochemical exchange with the atmosphere. At the global scale, the total river-atmosphere flux of trace gasses such as carbon dioxide depends on the proportion of Earth’s surface that is covered by the fluvial network, yet the total surface area of rivers and streams is poorly constrained. We used a global database of planform river hydromorphology and a statistical approach to show that global river and stream surface area at mean annual discharge is 773,000 ± 79,000 square kilometers (0.58 ± 0.06%) of Earth’s nonglaciated land surface, an area 44 ± 15% larger than previous spatial estimates. We found that rivers and streams likely play a greater role in controlling land-atmosphere fluxes than is currently represented in global carbon budgets.

Description: The color patterns of African cichlid fishes provide notable examples of phenotypic convergence. Across the more than 1200 East African rift lake species, melanic horizontal stripes have evolved numerous times. We discovered that regulatory changes of the gene agouti-related peptide 2 ( agrp2 ) act as molecular switches controlling this evolutionarily labile phenotype. Reduced agrp2 expression is convergently associated with the presence of stripe patterns across species flocks. However, cis-regulatory mutations are not predictive of stripes across radiations, suggesting independent regulatory mechanisms. Genetic mapping confirms the link between the agrp2 locus and stripe patterns. The crucial role of agrp2 is further supported by a CRISPR-Cas9 knockout that reconstitutes stripes in a nonstriped cichlid. Thus, we unveil how a single gene affects the convergent evolution of a complex color pattern.

Description: Snowshoe hares ( Lepus americanus ) maintain seasonal camouflage by molting to a white winter coat, but some hares remain brown during the winter in regions with low snow cover. We show that cis-regulatory variation controlling seasonal expression of the Agouti gene underlies this adaptive winter camouflage polymorphism. Genetic variation at Agouti clustered by winter coat color across multiple hare and jackrabbit species, revealing a history of recurrent interspecific gene flow. Brown winter coats in snowshoe hares likely originated from an introgressed black-tailed jackrabbit allele that has swept to high frequency in mild winter environments. These discoveries show that introgression of genetic variants that underlie key ecological traits can seed past and ongoing adaptation to rapidly changing environments.

Description: Maintenance of biodiversity in a rapidly changing climate will depend on the efficacy of evolutionary rescue, whereby population declines due to abrupt environmental change are reversed by shifts in genetically driven adaptive traits. However, a lack of traits known to be under direct selection by anthropogenic climate change has limited the incorporation of evolutionary processes into global conservation efforts. In 21 vertebrate species, some individuals undergo a seasonal color molt from summer brown to winter white as camouflage against snow, whereas other individuals remain brown. Seasonal snow duration is decreasing globally, and fitness is lower for winter white animals on snowless backgrounds. Based on 2713 georeferenced samples of known winter coat color—from eight species across trophic levels—we identify environmentally driven clinal gradients in winter coat color, including polymorphic zones where winter brown and white morphs co-occur. These polymorphic zones, underrepresented by existing global protected area networks, indicate hot spots for evolutionary rescue in a changing climate.

Description: Anyone awed by towering redwoods should offer thanks to stomata, the tiny pores on the leaves of all trees and other vascular plants. These microscopic mouths allow plants to grow tall and to regulate carbon dioxide intake and water loss. Stomata, in short, helped plants colonize the landscape and transform the planet. Now, molecular studies are giving scientists glimpses of the early days of stomata and how they have changed since then. They suggest complex stomata evolved to help early plants control moisture in their spore capsules and that other plants later exploited these pores to breathe in carbon dioxide and exhale water vapor. And hundreds of millions of years later, more sophisticated stomata evolved in grasses, enabling them to tightly control water loss—a feature that helped them dominate dry landscapes around the world. Author: Elizabeth Pennisi

Description: Author: Julia Fahrenkamp-Uppenbrink

Description: Avian egg shape is generally explained as an adaptation to life history, yet we currently lack a global synthesis of how egg-shape differences arise and evolve. Here, we apply morphometric, mechanistic, and macroevolutionary analyses to the egg shapes of 1400 bird species. We characterize egg-shape diversity in terms of two biologically relevant variables, asymmetry and ellipticity, allowing us to quantify the observed morphologies in a two-dimensional morphospace. We then propose a simple mechanical model that explains the observed egg-shape diversity based on geometric and material properties of the egg membrane. Finally, using phylogenetic models, we show that egg shape correlates with flight ability on broad taxonomic scales, suggesting that adaptations for flight may have been critical drivers of egg-shape variation in birds.

Description: Extreme environmental perturbations offer opportunities to observe the effects of natural selection in wild populations. During the winter of 2013–2014, the southeastern United States endured an extreme cold event. We used thermal performance, transcriptomics, and genome scans to measure responses of lizard populations to storm-induced selection. We found significant increases in cold tolerance at the species’ southern limit. Gene expression in southern survivors shifted toward patterns characteristic of northern populations. Comparing samples before and after the extreme winter, 14 genomic regions were differentiated in the surviving southern population; four also exhibited signatures of local adaptation across the latitudinal gradient and implicate genes involved in nervous system function. Together, our results suggest that extreme winter events can rapidly produce strong selection on natural populations at multiple biological levels that recapitulate geographic patterns of local adaptation.

Description: Author: Sacha Vignieri

Description: Author: Jake Yeston

Description: The phrase “perception is reality” is used in many contexts but is often not true. For example, human inability to perceive ultraviolet light does not negate its reality. Nevertheless, perception can cause reality to evolve. This is the insight of the study by Nachev et al. on page 75 of this issue (1). The authors integrated field and laboratory experiments with computer simulations to explain how perceptual mechanisms in a pollinator—a bat—can cause the evolution of counterintuitive traits in flowers. Author: Hamilton Farris

Description: Author: Jake Yeston

Description: Charles Darwin closed his first edition of On the Origin of Species with the poetic words: “There is grandeur in this view of life,…whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved” (1). Today, scientists are using genetics to understand how species multiply, and ecological and behavioral knowledge to understand why they do so. However, many questions remain about the sources of genetic variation and how new phenotypes arise in response to environmental change. Recent research has revealed unexpected origins of genetic variation, providing crucial insights into phenotypic divergence and the evolutionary effects of rare events triggered by global climatic change. Authors: B. Rosemary Grant, Peter R. Grant

Description: Author: Julia Fahrenkamp-Uppenbrink

Description: We used extensive data from a long-term study of great tits ( Parus major ) in the United Kingdom and Netherlands to better understand how genetic signatures of selection translate into variation in fitness and phenotypes. We found that genomic regions under differential selection contained candidate genes for bill morphology and used genetic architecture analyses to confirm that these genes, especially the collagen gene COL4A5 , explained variation in bill length. COL4A5 variation was associated with reproductive success, which, combined with spatiotemporal patterns of bill length, suggested ongoing selection for longer bills in the United Kingdom. Last, bill length and COL4A5 variation were associated with usage of feeders, suggesting that longer bills may have evolved in the United Kingdom as a response to supplementary feeding.

Description: Nachev et al . (Reports, 6 January 2017, p. 75) present dilute nectar in bat-pollinated plants as "paradoxical" because bats prefer concentrated nectar, but paradox disappears with realistic assumptions about nectar evolution. We argue that they make unrealistic assumptions about the cognitive abilities of bat pollinators, invoke Weber’s law inappropriately, and cannot predict observed nectar concentrations of bat flowers or negative correlations between pollinator body size and average concentration.

Description: Pyke and Waser claim that our virtual pollination ecology model makes unrealistic assumptions and fails to predict observed nectar concentrations of bat flowers and negative correlations between pollinator body size and sugar concentration. In their comment, crucial model features are misrepresented, misunderstood, or ignored. Sensitivity to the supply/demand ratio explains both the equilibrium concentrations and the selection for lower concentrations by larger pollinators.

Description: One of the most important developments in Earth's history is the change from the anaerobic environment of the early Earth to the aerobic and highly oxidizing environment that we have today, with 21% atmospheric oxygen (O2) (1). Many geologists, atmospheric scientists, and biologists have studied this dramatic change in the redox state of Earth—the “great oxidation event” (2)—to understand when and how it took place. On page 1436 of this issue, Soo et al. report exciting new evidence toward answers to both these questions (3). Author: Robert E. Blankenship

Description: Animals that wield toxins face self-intoxication. Poison frogs have a diverse arsenal of defensive alkaloids that target the nervous system. Among them is epibatidine, a nicotinic acetylcholine receptor (nAChR) agonist that is lethal at microgram doses. Epibatidine shares a highly conserved binding site with acetylcholine, making it difficult to evolve resistance yet maintain nAChR function. Electrophysiological assays of human and frog nAChR revealed that one amino acid replacement, which evolved three times in poison frogs, decreased epibatidine sensitivity but at a cost of acetylcholine sensitivity. However, receptor functionality was rescued by additional amino acid replacements that differed among poison frog lineages. Our results demonstrate how resistance to agonist toxins can evolve and that such genetic changes propel organisms toward an adaptive peak of chemical defense.

Description: Polynitrogens have the potential for ultrahigh-performing explosives or propellants because singly or doubly bonded polynitrogens can decompose to triply bonded dinitrogen (N2) with an extraordinarily large energy release. The large energy content and relatively low activation energy toward decomposition makes the synthesis of a stable polynitrogen allotrope an extraordinary challenge. Many elements exist in different forms (allotropes)—for example, carbon can exist as graphite, diamond, buckyballs, or graphene. However, no stable neutral allotropes are known for nitrogen, and only two stable homonuclear polynitrogen ions had been isolated until now—namely, the N3− anion (1) and the N5+ cation (2). On page 374 of this issue, Zhang et al. (3) report the synthesis and characterization of the first stable salt of the cyclo-N5− anion, only the third stable homonuclear polynitrogen ion ever isolated. Author: Karl O. Christe

Description: Mutualistic symbiotic relationships are those in which both species benefit; for example, the vivid colors of coral reefs come from symbiotic algae that provide their living coral hosts with nutrients and oxygen through photosynthesis in exchange for protection. A similar mutualistic relationship exists between gut-dwelling bacteria and their animal hosts (1). It remains unclear, however, to what degree symbiosis has shaped host-microbial interactions and coevolution. On page 380 of this issue, Moeller et al. show that gut bacterial strains cospeciated with hominids (apes and humans) over the past 15 million years (2). These findings set the stage for exploring the evolutionary processes that underlie the symbiotic relationship between hominids and their gut-dwelling microbes. Authors: Julia A. Segre, Nick Salafsky

Description: Author: Caroline Ash

Description: Several unprecedented videos of gelatinous sea creatures called comb jellies, or ctenophores, now threaten to upend the standard view of the evolution of the so-called through-gut. Comb jellies, jellyfish, sea sponges, and a few other creatures all were thought to lack an anus, which meant they had to eat and defecate through a single hole. These are descendants of some of the first animals to arise, so it has been thought that the through-gut and anus were an innovation that came after those lineages emerged—and perhaps something that drove the diversity of new animal forms. But on 15 March, at the Ctenopolooza meeting in St. Augustine, Florida, evolutionary biologist William Browne of the University of Miami in Florida debuted films of comb jellies pooping—and it wasn't through their mouths. Browne's videos elicited gasps from the audience, who is now rethinking when the through-gut first evolved—and whether it may have emerged more than once. Author: Amy Maxmen

Description: For years, scientists have debated where dogs came from. Did wolves first forge their special relationship with humans in Europe, or in Asia? The answer, according to a new study, is yes. Researchers report that genetic analysis of hundreds of canines—including a nearly 5000-year-old dog unearthed on the east coast of Ireland—reveals that dogs may have been domesticated twice, once in Asia and once in Europe or the Near East, although European ancestry has mostly vanished from today's dogs. The findings could resolve a rift that has roiled the canine origins community—but experts say a lot more work needs to be done to confirm them. Author: David Grimm

Description: One of the greatest symbols of the birth of evolutionary biology is Darwin's first sketch of an evolutionary tree, above which he wrote: “I think.” Not only are evolutionary trees central to how scientists conceptualize evolutionary processes, Darwin's words also capture a key aspect of evolutionary science: It is difficult to observe, forcing researchers to rely heavily on inference. In recent decades, studies of fast-growing microorganisms have allowed hypotheses about evolutionary processes to be tested experimentally (1). On page 1147 of this issue, Baym et al. (2) report a device for visualizing evolutionary branching as bacteria grow across a meter-scale agar slab. The results offer important insights into evolutionary dynamics in spatially extended systems. Authors: Luke McNally, Sam P. Brown

Description: The field of molecular evolution is concerned with evolutionary changes in genes and genomes and the underlying driving forces behind those changes. Current studies in molecular evolution are almost entirely retrospective, with a focus on the mutations that were fixed during evolution, and the conclusions are often explanatory, offering no predictive insights. Because only a tiny fraction of all mutations that have ever occurred during evolution have been fixed, the “successes” that we see today provide an incomplete or even biased understanding of the evolutionary process. One way to circumvent this problem is to obtain the whole fitness landscape of a gene to understand, prospectively, chance and necessity in evolution (see the figure). Two studies in this issue, by Li et al. on page 837 (1) and Puchta et al. on page 840 (2), each take on this challenge by characterizing the in vivo fitness landscape of two RNA genes. Authors: Xionglei He, Li Liu

Description: Author: Sacha Vignieri

Description: For many evolutionary biologists, nothing gets their dander up faster than suggesting evolution is anything other than the process of natural selection, acting on random mutations. So some are uneasy that the John Templeton Foundation has awarded $8.7 million to U.K., Swedish, and U.S. researchers for experimental and theoretical work intended to put a revisionist view of evolution, the so-called extended evolutionary synthesis, on a sounder footing. Using a variety of plants, animals, and microbes, the researchers will study the possibility that organisms can influence their own evolution and that inheritance can take place through routes other than the genetic material. Critics are against evolutionary biologists accepting this money and argue that evolutionary theory already embraces the best of these ideas. But others are pleased as the money should help clarify the importance of different aspects of the extended synthesis. Author: Elizabeth Pennisi

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Haddad, Nick M -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1166-7. doi: 10.1126/science.aad5072.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695, USA. nick_haddad@ncsu.ed.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785459" target="_blank"〉PubMed〈/a〉

Description: Telomeres are the protective end-complexes at the termini of eukaryotic chromosomes. Telomere attrition can lead to potentially maladaptive cellular changes, block cell division, and interfere with tissue replenishment. Recent advances in the understanding of human disease processes have clarified the roles of telomere biology, especially in diseases of human aging and in some aging-related processes. Greater overall telomere attrition predicts mortality and aging-related diseases in inherited telomere syndrome patients, and also in general human cohorts. However, genetically caused variations in telomere maintenance either raise or lower risks and progression of cancers, in a highly cancer type-specific fashion. Telomere maintenance is determined by genetic factors and is also cumulatively shaped by nongenetic influences throughout human life; both can interact. These and other recent findings highlight both causal and potentiating roles for telomere attrition in human diseases.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Blackburn, Elizabeth H -- Epel, Elissa S -- Lin, Jue -- CA096840/CA/NCI NIH HHS/ -- GM026259/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1193-8. doi: 10.1126/science.aab3389.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA. elizabeth.blackburn@ucsf.edu. ; Department of Psychiatry, University of California, San Francisco, CA 94143, USA. ; Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785477" target="_blank"〉PubMed〈/a〉

Description: Massive open online courses (MOOCs) are often characterized as remedies to educational disparities related to social class. Using data from 68 MOOCs offered by Harvard and MIT between 2012 and 2014, we found that course participants from the United States tended to live in more-affluent and better-educated neighborhoods than the average U.S. resident. Among those who did register for courses, students with greater socioeconomic resources were more likely to earn a certificate. Furthermore, these differences in MOOC access and completion were larger for adolescents and young adults, the traditional ages where people find on-ramps into science, technology, engineering, and mathematics (STEM) coursework and careers. Our findings raise concerns that MOOCs and similar approaches to online learning can exacerbate rather than reduce disparities in educational outcomes related to socioeconomic status.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hansen, John D -- Reich, Justin -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1245-8. doi: 10.1126/science.aab3782. Epub 2015 Dec 3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Harvard Graduate School of Education, Harvard University, Cambridge, MA 02138, USA. john_hansen@mail.harvard.edu. ; Office of Digital Learning, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785488" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Underwood, Emily -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1188-90. doi: 10.1126/science.350.6265.1188.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785475" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Escobar, Herton -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1138-9. doi: 10.1126/science.350.6265.1138. Epub 2015 Dec 3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785449" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Scheid, Johannes F -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1175. doi: 10.1126/science.aad7133.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Massachusetts General Hospital, Boston, MA 02114, USA. The Rockefeller University, New York, NY 10021, USA. fscheid@partners.org.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785466" target="_blank"〉PubMed〈/a〉

Description: Congenital heart disease (CHD) patients have an increased prevalence of extracardiac congenital anomalies (CAs) and risk of neurodevelopmental disabilities (NDDs). Exome sequencing of 1213 CHD parent-offspring trios identified an excess of protein-damaging de novo mutations, especially in genes highly expressed in the developing heart and brain. These mutations accounted for 20% of patients with CHD, NDD, and CA but only 2% of patients with isolated CHD. Mutations altered genes involved in morphogenesis, chromatin modification, and transcriptional regulation, including multiple mutations in RBFOX2, a regulator of mRNA splicing. Genes mutated in other cohorts examined for NDD were enriched in CHD cases, particularly those with coexisting NDD. These findings reveal shared genetic contributions to CHD, NDD, and CA and provide opportunities for improved prognostic assessment and early therapeutic intervention in CHD patients.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Homsy, Jason -- Zaidi, Samir -- Shen, Yufeng -- Ware, James S -- Samocha, Kaitlin E -- Karczewski, Konrad J -- DePalma, Steven R -- McKean, David -- Wakimoto, Hiroko -- Gorham, Josh -- Jin, Sheng Chih -- Deanfield, John -- Giardini, Alessandro -- Porter, George A Jr -- Kim, Richard -- Bilguvar, Kaya -- Lopez-Giraldez, Francesc -- Tikhonova, Irina -- Mane, Shrikant -- Romano-Adesman, Angela -- Qi, Hongjian -- Vardarajan, Badri -- Ma, Lijiang -- Daly, Mark -- Roberts, Amy E -- Russell, Mark W -- Mital, Seema -- Newburger, Jane W -- Gaynor, J William -- Breitbart, Roger E -- Iossifov, Ivan -- Ronemus, Michael -- Sanders, Stephan J -- Kaltman, Jonathan R -- Seidman, Jonathan G -- Brueckner, Martina -- Gelb, Bruce D -- Goldmuntz, Elizabeth -- Lifton, Richard P -- Seidman, Christine E -- Chung, Wendy K -- T32 HL007208/HL/NHLBI NIH HHS/ -- Arthritis Research UK/United Kingdom -- British Heart Foundation/United Kingdom -- Department of Health/United Kingdom -- Howard Hughes Medical Institute/ -- Wellcome Trust/United Kingdom -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1262-6. doi: 10.1126/science.aac9396.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Genetics, Harvard Medical School, Boston, MA, USA. Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA. ; Department of Genetics, Yale University School of Medicine, New Haven, CT, USA. ; Departments of Systems Biology and Biomedical Informatics, Columbia University Medical Center, New York, NY, USA. ; Department of Genetics, Harvard Medical School, Boston, MA, USA. NIHR Cardiovascular Biomedical Research Unit at Royal Brompton & Harefield NHS Foundation and Trust and Imperial College London, London, UK. National Heart & Lung Institute, Imperial College London, London, UK. ; Department of Genetics, Harvard Medical School, Boston, MA, USA. Analytical and Translational Genetics Unit, Massachusetts General Hospital and Harvard Medical School, Boston MA, USA. ; Department of Genetics, Harvard Medical School, Boston, MA, USA. Howard Hughes Medical Institute, Harvard University, Boston, MA, USA. ; Department of Genetics, Harvard Medical School, Boston, MA, USA. ; Department of Cardiology, University College London and Great Ormond Street Hospital, London, UK. ; Department of Pediatrics, University of Rochester Medical Center, The School of Medicine and Dentistry, Rochester, NY, USA. ; Section of Cardiothoracic Surgery, University of Southern California Keck School of Medicine, Los Angeles, CA, USA. ; Department of Genetics, Yale University School of Medicine, New Haven, CT, USA. Yale Center for Genome Analysis, Yale University, New Haven, CT, USA. ; Yale Center for Genome Analysis, Yale University, New Haven, CT, USA. ; Steven and Alexandra Cohen Children's Medical Center of New York, New Hyde Park, NY, USA. ; Departments of Systems Biology and Biomedical Informatics, Columbia University Medical Center, New York, NY, USA. Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, USA. ; Department of Neurology, Columbia University Medical Center, New York, NY, USA. ; Department of Pediatrics, Columbia University Medical Center, New York, NY, USA. ; Department of Cardiology, Children's Hospital Boston, Boston, MA, USA. ; Division of Pediatric Cardiology, University of Michigan, Ann Arbor, MI, USA. ; Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada. ; Department of Cardiology, Boston Children's Hospital, Boston, MA, USA. ; Department of Pediatric Cardiac Surgery, The Children's Hospital of Philadelphia, Philadelphia, PA, USA. ; Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA. ; Department of Psychiatry, University of California San Francisco, San Francisco, CA, USA. ; Heart Development and Structural Diseases Branch, Division of Cardiovascular Sciences, NHLBI/NIH, Bethesda, MD, USA. ; Department of Genetics, Yale University School of Medicine, New Haven, CT, USA. bruce.gelb@mssm.edu goldmuntz@email.chop.edu martina.brueckner@yale.edu richard.lifton@yale.edu cseidman@genetics.med.harvard.edu wkc15@cumc.columbia.edu. ; Mindich Child Health and Development Institute and Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA. bruce.gelb@mssm.edu goldmuntz@email.chop.edu martina.brueckner@yale.edu richard.lifton@yale.edu cseidman@genetics.med.harvard.edu wkc15@cumc.columbia.edu. ; Department of Pediatrics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Division of Cardiology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA. bruce.gelb@mssm.edu goldmuntz@email.chop.edu martina.brueckner@yale.edu richard.lifton@yale.edu cseidman@genetics.med.harvard.edu wkc15@cumc.columbia.edu. ; Department of Genetics, Yale University School of Medicine, New Haven, CT, USA. Howard Hughes Medical Institute, Yale University, New Haven, CT, USA. bruce.gelb@mssm.edu goldmuntz@email.chop.edu martina.brueckner@yale.edu richard.lifton@yale.edu cseidman@genetics.med.harvard.edu wkc15@cumc.columbia.edu. ; Department of Genetics, Harvard Medical School, Boston, MA, USA. Howard Hughes Medical Institute, Harvard University, Boston, MA, USA. Cardiovascular Division, Brigham & Women's Hospital, Harvard University, Boston, MA, USA. bruce.gelb@mssm.edu goldmuntz@email.chop.edu martina.brueckner@yale.edu richard.lifton@yale.edu cseidman@genetics.med.harvard.edu wkc15@cumc.columbia.edu. ; Departments of Pediatrics and Medicine, Columbia University Medical Center, New York, NY, USA. bruce.gelb@mssm.edu goldmuntz@email.chop.edu martina.brueckner@yale.edu richard.lifton@yale.edu cseidman@genetics.med.harvard.edu wkc15@cumc.columbia.edu.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785492" target="_blank"〉PubMed〈/a〉

Description: Nicotinamide adenine dinucleotide (NAD(+)) is a coenzyme found in all living cells. It serves both as a critical coenzyme for enzymes that fuel reduction-oxidation reactions, carrying electrons from one reaction to another, and as a cosubstrate for other enzymes such as the sirtuins and poly(adenosine diphosphate-ribose) polymerases. Cellular NAD(+) concentrations change during aging, and modulation of NAD(+) usage or production can prolong both health span and life span. Here we review factors that regulate NAD(+) and discuss how supplementation with NAD(+) precursors may represent a new therapeutic opportunity for aging and its associated disorders, particularly neurodegenerative diseases.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Verdin, Eric -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1208-13. doi: 10.1126/science.aac4854.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Gladstone Institutes, Department of Medicine, University of California, San Francisco, San Francisco, CA 94158, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785480" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hurtley, Stella -- Roberts, Leslie -- Ray, L Bryan -- Purnell, Beverly A -- Ash, Caroline -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1180-1. doi: 10.1126/science.350.6265.1180.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785472" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ford, Adam T -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1175. doi: 10.1126/science.aad7134.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Integrative Biology at the University of Guelph, Guelph, Ontario, Canada. adamford@uoguelph.ca.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785465" target="_blank"〉PubMed〈/a〉

Description: Flow regulation and irrigation alter local freshwater conditions, but their global effects are highly uncertain. We investigated these global effects from 1901 to 2008, using hydroclimatic observations in 100 large hydrological basins. Globally, we find consistent and dominant effects of increasing relative evapotranspiration from both activities, and decreasing temporal runoff variability from flow regulation. The evapotranspiration effect increases the long-term average human consumption of fresh water by 3563 +/- 979 km(3)/year from 1901-1954 to 1955-2008. This increase raises a recent estimate of the current global water footprint of humanity by around 18%, to 10,688 +/- 979 km(3)/year. The results highlight the global impact of local water-use activities and call for their relevant account in Earth system modeling.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jaramillo, Fernando -- Destouni, Georgia -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1248-51. doi: 10.1126/science.aad1010.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physical Geography and Bolin Centre for Climate Research, Stockholm University, SE-106 91, Stockholm, Sweden. Department of Biological and Environmental Sciences, University of Gothenburg, 40530 Goteborg, Sweden. fernando.jaramillo@natgeo.su.se. ; Department of Physical Geography and Bolin Centre for Climate Research, Stockholm University, SE-106 91, Stockholm, Sweden.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785489" target="_blank"〉PubMed〈/a〉

Description: The potential for the gut microbiota to affect health has a particular relevance for older individuals. This is because the microbiota may modulate aging-related changes in innate immunity, sarcopaenia, and cognitive function, all of which are elements of frailty. Both cell culture-dependent and -independent studies show that the gut microbiota of older people differs from that of younger adults. There is no chronological threshold or age at which the composition of the microbiota suddenly alters; rather, changes occur gradually with time. Our detailed analyses have separated the microbiota into groups associated with age, long-term residential care, habitual diet, and degree of retention of a core microbiome. We are beginning to understand how these groups change with aging and how they relate to clinical phenotypes. These data provide a framework for analyzing microbiota-health associations, distinguishing correlation from causation, identifying microbiota interaction with physiological aging processes, and developing microbiota-based health surveillance for older adults.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉O'Toole, Paul W -- Jeffery, Ian B -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1214-5. doi: 10.1126/science.aac8469.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉School of Microbiology and APC Microbiome Institute, University College Cork, Cork T12 Y337, Ireland. pwotoole@ucc.ie. ; School of Microbiology and APC Microbiome Institute, University College Cork, Cork T12 Y337, Ireland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785481" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Akiyama, Hiroko -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1135. doi: 10.1126/science.aad9386.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Hiroko Akiyama is a professor at the Institute of Gerontology at the University of Tokyo, 7-3-1 Hongo, Bunkyoku, Tokyo, Japan. akiyama@iog.u-tokyo.ac.jp.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785447" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Alexandrov, Ludmil B -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1175. doi: 10.1126/science.aad7363.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Theoretical Biology and Biophysics (T-6), Los Alamos National Laboratory, Los Alamos, NM 87545, USA. lba@lanl.gov.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785464" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Amigo, Ignacio -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1286. doi: 10.1126/science.350.6265.1286.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Ignacio Amigo is a postdoctoral researcher in the biochemistry department of the Chemistry Institute at the University of Sao Paulo in Brazil. Send your story to SciCareerEditor@aaas.org.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785493" target="_blank"〉PubMed〈/a〉

Description: Age is the greatest risk factor for nearly every major cause of mortality in developed nations. Despite this, most biomedical research focuses on individual disease processes without much consideration for the relationships between aging and disease. Recent discoveries in the field of geroscience, which aims to explain biological mechanisms of aging, have provided insights into molecular processes that underlie biological aging and, perhaps more importantly, potential interventions to delay aging and promote healthy longevity. Here we describe some of these advances, along with efforts to move geroscience from the bench to the clinic. We also propose that greater emphasis should be placed on research into basic aging processes, because interventions that slow aging will have a greater effect on quality of life compared with disease-specific approaches.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kaeberlein, Matt -- Rabinovitch, Peter S -- Martin, George M -- P30AG013280/AG/NIA NIH HHS/ -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1191-3. doi: 10.1126/science.aad3267.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pathology, University of Washington, Seattle, WA 98195, USA. kaeber@uw.edu. ; Department of Pathology, University of Washington, Seattle, WA 98195, USA. ; Department of Pathology, University of Washington, Seattle, WA 98195, USA. Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785476" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cohen, Jon -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1186-7. doi: 10.1126/science.350.6265.1186.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785474" target="_blank"〉PubMed〈/a〉

Description: Research into stem cells and aging aims to understand how stem cells maintain tissue health, what mechanisms ultimately lead to decline in stem cell function with age, and how the regenerative capacity of somatic stem cells can be enhanced to promote healthy aging. Here, we explore the effects of aging on stem cells in different tissues. Recent research has focused on the ways that genetic mutations, epigenetic changes, and the extrinsic environmental milieu influence stem cell functionality over time. We describe each of these three factors, the ways in which they interact, and how these interactions decrease stem cell health over time. We are optimistic that a better understanding of these changes will uncover potential strategies to enhance stem cell function and increase tissue resiliency into old age.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Goodell, Margaret A -- Rando, Thomas A -- P01 AG036695/AG/NIA NIH HHS/ -- R01 AG047820/AG/NIA NIH HHS/ -- R01 AR062185/AR/NIAMS NIH HHS/ -- R37 AG023806/AG/NIA NIH HHS/ -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1199-204. doi: 10.1126/science.aab3388.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Stem Cells and Regenerative Medicine Center, Center for Cell and Gene Therapy, and Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA. goodell@bcm.edu rando@stanford.edu. ; Glenn Center for the Biology of Aging and Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA, and Center for Regenerative Rehabilitation, Veterans Administration Palo Alto Health Care System, Palo Alto, CA 94304, USA. goodell@bcm.edu rando@stanford.edu.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785478" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Greenbaum, Dov -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1176. doi: 10.1126/science.350.6265.1176-a.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Zvi Meitar Institute for Legal Implications of Emerging Technologies, Interdisciplinary Center, Herzliya Israel and Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 10463, USA. dov.greenbaum@yale.edu.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785467" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Grimm, David -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1182-5. doi: 10.1126/science.350.6265.1182.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785473" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Young, Ry -- Gill, Jason J -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1163-4. doi: 10.1126/science.aad6791.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA. Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA. ryland@tamu.edu jason.gill@tamu.edu. ; Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA. Department of Animal Science, Texas A&M University, College Station, TX 77843, USA. ryland@tamu.edu jason.gill@tamu.edu.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785457" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gura, Trisha -- New York, N.Y. -- Science. 2015 Dec 4;350(6265):1139-40. doi: 10.1126/science.350.6265.1139.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26785450" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kupferschmidt, Kai -- New York, N.Y. -- Science. 2016 Apr 8;352(6282):128-9. doi: 10.1126/science.352.6282.128. Epub 2016 Apr 7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27124428" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kupferschmidt, Kai -- New York, N.Y. -- Science. 2016 Mar 11;351(6278):1143. doi: 10.1126/science.351.6278.1143.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26965608" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kupferschmidt, Kai -- New York, N.Y. -- Science. 2016 Apr 22;352(6284):391-2. doi: 10.1126/science.352.6284.391. Epub 2016 Apr 21.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27102452" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kupferschmidt, Kai -- New York, N.Y. -- Science. 2016 Mar 11;351(6278):1136-7. doi: 10.1126/science.351.6278.1136.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26965604" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Segal, Rosalind A -- New York, N.Y. -- Science. 2016 Mar 25;351(6280):1494. doi: 10.1126/science.351.6280.1494.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Rosalind A. Segal is a neurobiology professor at Harvard Medical School and co-chair of cancer biology at the Dana-Farber Cancer Institute in Boston. Send your story to SciCareerEditor@aaas.org.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27013735" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Claiborne, Anne B -- English, Rebecca A -- Kahn, Jeffrey P -- 10002265/PHS HHS/ -- New York, N.Y. -- Science. 2016 Feb 12;351(6274):668-70. doi: 10.1126/science.aaf3091. Epub 2016 Feb 3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Medicine, U.S. National Academies of Sciences, Engineering, and Medicine, Washington, DC 20001, USA. aclaiborne@nas.edu. ; Institute of Medicine, U.S. National Academies of Sciences, Engineering, and Medicine, Washington, DC 20001, USA. ; Johns Hopkins Berman Institute of Bioethics, Johns Hopkins University, Baltimore, MD 21205, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26842937" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lawler, Andrew -- New York, N.Y. -- Science. 2016 Apr 15;352(6283):280-1. doi: 10.1126/science.352.6283.280.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27081048" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Servick, Kelly -- New York, N.Y. -- Science. 2016 Mar 11;351(6278):1130-2. doi: 10.1126/science.351.6278.1130.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26965601" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Servick, Kelly -- New York, N.Y. -- Science. 2016 Jan 1;351(6268):15. doi: 10.1126/science.351.6268.15.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26721984" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lawler, Andrew -- New York, N.Y. -- Science. 2016 Apr 29;352(6285):501-2. doi: 10.1126/science.352.6285.501.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27126014" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lawler, Andrew -- New York, N.Y. -- Science. 2016 Jan 8;351(6269):111-2. doi: 10.1126/science.351.6269.111.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26744387" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cohen, Jon -- New York, N.Y. -- Science. 2016 Jan 29;351(6272):434. doi: 10.1126/science.351.6272.434.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26823407" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cohen, Jon -- New York, N.Y. -- Science. 2016 Jan 1;351(6268):16-9. doi: 10.1126/science.351.6268.16.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26721985" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shanahan, Jesse -- New York, N.Y. -- Science. 2016 Jan 22;351(6271):418. doi: 10.1126/science.351.6271.418.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Jesse Shanahan is a master's student in astronomy at Wesleyan University in Middletown, Connecticut. Send your story to SciCareerEditor@aaas.org.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26798017" target="_blank"〉PubMed〈/a〉