Editors' Choice

Science  19 Jan 2018:
Vol. 359, Issue 6373, pp. 286
  1. Conservation

    How hunting affects brown bear populations

    1. Julia Fahrenkamp-Uppenbrink

    Hunting is the leading cause of death for brown bears older than 3 years in Sweden.

    PHOTO: ONDREJ PROSICKY/SHUTTERSTOCK.COM

    In many parts of the world, regulated hunting is used to control the size of predator populations such as wolves and brown bears. Bischof et al. explore how such regulated hunting affects the life history and demography of a brown bear population in Sweden that has been monitored continuously since 1985. The study shows that hunting was the leading cause of death for bears aged more than 3 years, resulting in reduced life expectancy; this contrasts with natural conditions, where mortality is reduced once bears reach adulthood. Hunting also substantially reduces the reproductive value—that is, the number of future offspring that female bears of a given age are expected to have. Thus, even if a carnivore population recovers numerically, regulated hunting transforms its makeup in multiple ways that need to be taken into account in management.

    Nat. Ecol. Evol. 2, 116 (2018).

  2. Geophysics

    Going dry in the Pacific Northwest

    1. Brent Grocholski

    Volcanic belts such as the Andes result from deep melting as water dragged down during subduction fluxes into the crust. Canales et al. show that the Juan de Fuca slab, which is subducting below the Pacific Northwest in North America, is much drier than other subducting slabs. The distribution of water in the slab may help determine the origins of seismic tremor and episodic slip that occur in this region. It also confirms a hypothesis that volcanism in the region is not the result of the influence of water, but rather is due to the decompression trigger melting more commonly seen along midocean ridges.

    Nat. Geosci. 10, 864–870 (2017).

  3. Molecular Biology

    Time-out for mRNAs in the nucleus

    1. Steve Mao

    Cell cycle events are precisely orchestrated to ensure accurate cell division. Yang et al. have discovered that sequestering mature mRNAs in the nucleus modulates cell cycle players. In dividing Arabidopsis cells, nuclear retention of CDC20 and CCS52B mRNAs prevents them from being released into the cytoplasm until the nuclear envelope breaks down at prometaphase. Released mRNAs are rapidly translated into proteins, ensuring their regulatory functions at the proper cell cycle stage. Similar nuclear sequestration strategies may be used for other mRNAs in different cellular contexts.

    Mol. Cell. 10.1016/j.molcel.2017.11.008 (2017).

  4. Neuroscience

    Serious damage by soluble tau

    1. Peter Stern

    Alterations in the metabolism of the neuronal microtubule-associated protein tau are central to several neurodegenerative diseases. In these diseases, tau usually loses solubility and forms aggregates that impair cell function to trigger neuronal cell death and neurodegeneration. However, the in vivo neurotoxic potential of soluble tau is not yet fully understood. Bolós et al. stereotactically injected human soluble tau into the dentate gyrus of mice. Hippocampal granule neurons showed markedly reduced synapse numbers in the molecular layer. In addition, newborn granule cells showed reduced numbers of dendritic spines. Behaviorally, these animals exhibited an impaired capacity to perform pattern separation. Soluble tau thus causes long-term damage to the morphology and connectivity of newborn granule cells.

    Transl. Psych. 10.1038/s41398-017-0013-6 (2017).

  5. RNA Folding

    Lighting up riboswitching

    1. Valda Vinson

    RNAs fold as they are synthesized, and this folding is required for function. Uhm et al. describe a single-molecule fluorescence energy transfer assay to monitor cotranscriptional RNA folding. This approach revealed folding in the thiamine pyrophosphate (TPP) riboswitch that regulates translation of genes involved in the synthesis of thiamine, an essential vitamin. The riboswitch folds into the “off” conformation, in which translation is inhibited, even in the absence of the TPP ligand. If TPP is not bound to this off conformation, it can switch to the “on” conformation when transcription pauses near the translation start codon, and this allows translation to start. TPP binding stabilizes the off conformation and prevents the switch. The assay will allow investigation of other cases in which transcriptional speed and pausing affect RNA folding.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1712983115 (2017).

  6. Brain Development

    The value of scaffolds

    1. Pamela J. Hines

    Neurons migrate to form surface layers of the chick brain.

    PHOTO: F. GARCIA-MORENO ET AL. CELL REP. 22, 96 (2018)

    The brain is built by groups of neurons that migrate and interdigitate to form layers and circuits. This process varies in different phyla of animals. García-Moreno et al. draw lessons from the development of the chick brain to understand what makes the mammalian brain distinctive. In mammals, excitatory glutamatergic neurons born deep in the brain migrate radially to the cortex, whereas inhibitory GABAergic interneurons born elsewhere migrate tangentially across the cortex. And, like the external scaffolds on a building under construction, some glutamatergic neurons migrate tangentially, instruct organization, then disappear. The developing chick brain, although it has tangentially migrating interneurons, lacks the tangentially migrating transient neurons.

    Cell Rep. 22, 96 (2018).

  7. Science Careers

    Social skills to pay the bills

    1. Brad Wible

    Employment requiring high math skills but low social skills, including many science and engineering jobs, has decreased in the United States as high social skills have become increasingly powerful predictors of employment and wage growth. Using surveys of occupations, skills, and wages, Deming shows that socially skilled people self-select into less structured jobs requiring a wide range of tasks, leading to wage gains. Increasing computerization may be a driver, replacing routine work and prioritizing social collaboration, but employment and wages have been especially strong in jobs demanding both high math and high social skills.

    Quart. J. Econ. 132, 1593 (2017).