Catálogo de publicaciones - revistas

<jats:p> We used 20 de novo genome assemblies to probe the speciation history and architecture of gene flow in rapidly radiating <jats:italic>Heliconius</jats:italic> butterflies. Our tests to distinguish incomplete lineage sorting from introgression indicate that gene flow has obscured several ancient phylogenetic relationships in this group over large swathes of the genome. Introgressed loci are underrepresented in low-recombination and gene-rich regions, consistent with the purging of foreign alleles more tightly linked to incompatibility loci. Here, we identify a hitherto unknown inversion that traps a color pattern switch locus. We infer that this inversion was transferred between lineages by introgression and is convergent with a similar rearrangement in another part of the genus. These multiple de novo genome sequences enable improved understanding of the importance of introgression and selective processes in adaptive radiation. </jats:p>

<jats:title>The toll of measles on the immune system</jats:title> <jats:p> Many of the deaths attributable to measles virus are caused by secondary infections because the virus infects and functionally impairs immune cells. Whether measles infection causes long-term damage to immune memory has been unclear. This question has become increasingly important given the resurgence in measles epidemics worldwide. Using a blood test called VirScan, Mina <jats:italic>et al.</jats:italic> comprehensively analyzed the antibody repertoire in children before and after natural infection with measles virus as well as in children before and after measles vaccination. They found that measles infection can greatly diminish previously acquired immune memory, potentially leaving individuals at risk for infection by other pathogens. These adverse effects on the immune system were not seen in vaccinated children. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6465" page="599" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aay6485">599</jats:related-article> </jats:p>

<jats:title>Protecting plants from the inside out</jats:title> <jats:p> Some soils show a remarkable ability to suppress disease caused by plant pathogens, an ability that is attributed to plant-associated microbiota. Carrión <jats:italic>et al.</jats:italic> investigated the role of endophytes, the intimate microbial community found within roots, in fungal disease suppression (see the Perspective by Tringe). The wilt fungus <jats:italic>Rhizoctonia solani</jats:italic> infects sugar beets, whereupon transcriptional analysis shows that several bacterial endophyte species activate biosynthetic gene clusters to cause disease suppression. These organisms produce antifungal effectors, including enzymes that can digest fungal cell walls, and secondary metabolites, including phenazines, polyketides, and siderophores, which may contribute to the antifungal phenotype. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6465" page="606" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aaw9285">606</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6465" page="568" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aaz5619">568</jats:related-article> </jats:p>

<jats:title>Quantum sieves for hydrogen isotopes</jats:title> <jats:p> One method for improving the efficiency of separation of hydrogen from deuterium (D) is to exploit kinetic quantum sieving with nanoporous solids. This method requires ultrafine pore apertures (around 3 angstroms), which usually leads to low pore volumes and low D <jats:sub>2</jats:sub> adsorption capacities. Liu <jats:italic>et al.</jats:italic> used organic synthesis to tune the pore size of the internal cavities of organic cage molecules. A hybrid cocrystal contained both a small-pore cage that imparted high selectivity and a larger-pore cage that enabled high D <jats:sub>2</jats:sub> uptake. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6465" page="613" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aax7427">613</jats:related-article> </jats:p>

<jats:title>Cascading effects of pesticide use</jats:title> <jats:p> It is now well known that neonicotinoids negatively affect pollinators. As research has expanded, it has become clear that these globally used insecticides directly affect other ecosystem components, including vertebrates. Yamamuro <jats:italic>et al.</jats:italic> now show that these compounds are indirectly affecting species through trophic cascades (see the Perspective by Jensen). Since the application of neonicotinoids to agricultural fields began in the 1990s, zooplankton biomass has plummeted in a Japanese lake surrounded by these fields. This decline has led to shifts in food web structure and a collapse of two commercially harvested freshwater fish species. The authors argue that such dynamics are likely occurring widely. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6465" page="620" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aax3442">620</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6465" page="566" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aaz6436">566</jats:related-article> </jats:p>

<jats:title>Single molecules sense spin</jats:title> <jats:p> Imaging surface magnetism, and, in particular, spin excitations of adsorbed molecules or films, is challenging. Verlhac <jats:italic>et al.</jats:italic> demonstrate spin-sensing capability by using the magnetic exchange interaction between a surface sample and the spin-excited states of a nickelocene molecule attached to a scanning tunneling microscope tip. The spatial dependence of the exchange field at the atomic scale enabled imaging of magnetic corrugation with atomic-scale lateral resolution for iron atoms and small islands of cobalt atoms absorbed on nonmagnetic copper surfaces. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6465" page="623" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aax8222">623</jats:related-article> </jats:p>

<jats:title>Fluid dynamics during sleep</jats:title> <jats:p> During non–rapid eye movement sleep, low-frequency oscillations in neural activity support memory consolidation and neuronal computation. Sleep is also associated with increased interstitial fluid volume and clearance of metabolic waste products. It is unknown why these processes co-occur and how they are related. Fultz <jats:italic>et al.</jats:italic> simultaneously measured electrophysiological, hemodynamic, and flow signals in the human brain (see the Perspective by Grubb and Lauritzen). Large oscillations of fluid inflow to the brain appeared during sleep and were tightly coupled to functional magnetic resonance imaging signals and entrained to electroencephalogram slow waves. Slow oscillatory neuronal activity thus leads to oscillations in blood volume, drawing cerebrospinal fluid into and out of the brain. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6465" page="628" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aax5440">628</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6465" page="572" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aaz5191">572</jats:related-article> </jats:p>

<jats:title>Order in the cytoplasm</jats:title> <jats:p> Extracts of the very large eggs of the African clawed frog, <jats:italic>Xenopus laevis</jats:italic> , have proven a valuable model system for the study of cell division. Cheng and Ferrell found that after homogenization, such cytoplasm can reorganize back into cell-like structures and undergo multiple rounds of division (see the Perspective by Mitchison and Field). This reorganization apparently occurs without the usual factors that are known to lead to such structural changes during cell division, such as F-actin, myosin II, various individual kinesins, aurora kinase A, or DNA. What is required is energy from adenosine triphosphate, microtubule polymerization, cytoplasmic dynein activity, and a specific kinase-involved cell cycle progression. Nongenetic information in the cytoplasm is apparently sufficient for basic spatial organization of the cell. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6465" page="631" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aav7793">631</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6465" page="569" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aaz5635">569</jats:related-article> </jats:p>

<jats:title>A black hole hiding in a binary star</jats:title> <jats:p> As material falls toward a black hole, it heats up and emits x-rays. Almost all black holes are discovered by this x-ray emission. Thompson <jats:italic>et al.</jats:italic> observed light from a giant star that is Doppler shifted, indicating an orbit around a binary companion. The companion object must weigh more than 2.6 solar masses, but it emits no light, including x-rays. This indicates the presence of a black hole that is not currently consuming any material. There may be a population of similarly hidden black holes that have been missed by x-ray observations. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6465" page="637" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aau4005">637</jats:related-article> </jats:p>

<jats:title>Unveiling African swine fever virus</jats:title> <jats:p> African swine fever virus (ASFV) is highly contagious and often lethal. With no vaccine or effective treatment, infections often require large-scale culling of pigs. Wang <jats:italic>et al.</jats:italic> apply cutting-edge cryo–electron microscopy techniques to determine the structure of this very large DNA virus. An 8.8-angstrom-resolution reconstruction shows the five layers of the virus, and the fourth capsid layer could be reconstructed at 4.8-angstrom resolution. The structure reveals epitopes in the major capsid protein that distinguish ASFV from other nucleocytoplasmic large DNA viruses and shows how the minor capsid proteins stabilize the capsid. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6465" page="640" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aaz1439">640</jats:related-article> </jats:p>