Editors' Choice

Science  30 Nov 2018:
Vol. 362, Issue 6418, pp. 1015
  1. Plant Genomics

    Columbine's puzzling chromosome

    1. Laura M. Zahn

    Aquilegia coerulea is found widely around the Northern Hemisphere.

    PHOTO: ISTOCK.COM/MICHAELJUST

    The columbine genus Aquilegia is found across the Northern Hemisphere and arose through two adaptive radiations, giving rise to 70 extant species. Filiault et al. deep sequenced Aquilegia coerulea to create a reference genome and compared it to 10 other sequenced Aquilegia spp. from Europe, Asia, and North America. Although the genomes generally exhibited low genetic diversity within species, consistent with previous studies, chromosome 4 showed an overall greater diversity, a higher number of older genetic variants, and different phylogenetic relationships among the species. The differences in chromosome 4 relative to the rest of the genome may be due to hybridization among species and a differential reduction in selection after Aquilegia diversified for this chromosome.

    eLife 7, e36426 (2018).

  2. Biotechnology

    Precision genome engineering

    1. Gemma Alderton

    Genome editing through CRISPR-Cas systems has the potential to correct genetic mutations that occur in diseased cells, such as cancer cells. However, the ability to selectively activate CRISPR-Cas systems in diseased cells is important to ensure that gene editing only occurs where it is wanted. Zhu et al. developed a system whereby gene editing could be activated by a magnetic field, thus allowing spatial control. The use of nanomagnets in their system also improved transduction into target cells in tumor-bearing mouse models. This approach could potentially allow the translation of CRISPR-Cas systems into therapeutic agents.

    Nat. Biomed. Eng. 10.1038/s41551-018-0318-7 (2018).

  3. Disease Prevention

    Some fishy supplements?

    1. Paula A. Kiberstis

    Fish, like these Pacific flatiron herring, are a source of omega-3 fatty acids and vitamin D.

    PHOTO: STEVE BLOOM IMAGES/ALAMY STOCK PHOTO

    More than half of the adult population in the United States consumes dietary supplements in the hope of staving off common, life-threatening diseases. Omega-3 fatty acids (fish oil) and vitamin D are especially popular because animal studies and small observational studies hinted that they prevent heart disease and cancer. Manson et al. tested these supplements in a randomized placebo-controlled trial of 26,000 people 50 years of age and older. At a median follow-up time of 5 years, there was no evidence that the supplements provided health benefits; the incidences of cancer and cardiovascular disease in the supplement group were similar to those in the placebo group.

    New Engl. J. Med. 10.1056/NEJMoa1809944, 10.1056/NEJMoa1811403 (2018).

  4. Platelets

    Transfusions for preterm babies

    1. Priscilla N. Kelly

    Platelets are immune cell fragments that act like molecular band-aids to control bleeding and help blood to clot. Premature babies can have abnormally low platelet numbers (thrombocytopenia) in the days after birth and are often given platelet transfusions to help prevent infections. Curley et al. studied >600 babies in a randomized clinical trial to determine just how low platelets have to get to warrant intervention. Only those infants with severely low platelet levels (<25,000 per cubic millimeter; normal is around 150,000) benefited from transfusion. By contrast, thrombocytopenic babies with somewhat higher platelet counts (<50,000 per cubic millimeter) that received more transfusions had poorer outcomes and an increased rate of death. These surprising findings suggest that not all babies with low platelet counts should receive a prophylactic transfusion, which should lead to safer management of premature babies.

    N. Engl. J. Med. 10.1056/NEJMoa1807320 (2018).

  5. Linguistics

    The linguistic expression of senses

    1. Tage S. Rai

    In Western cultures, it has been argued that vision and hearing are the senses that are most easily expressed in language. One theory holds that this ease of expression for some senses over others is due to universal features of perception. To test whether there is a universal hierarchy of senses, Majid et al. examined how sensory stimuli are linguistically coded across 20 unrelated languages. They found little evidence for a hierarchy of senses, suggesting that although vision and hearing may be the senses most accessible to English speakers, this may not be true in other cultures. These data have implications for understanding the relative influences of culture and language on perceptual experience.

    Proc. Natl. Acad. Sci. U.S.A. 115, 11369 (2018).

  6. Climate Change

    Energy, rain, and the future

    1. H. Jesse Smith

    The intensification of precipitation over land owing to rising atmospheric temperature is expected to increase in the 21st century, but there are still many details about why and how much that need to be better understood. Richardson et al. used a suite of climate models to analyze the atmospheric energy budget and its effects on the fast (due to atmospheric components like carbon dioxide and sulfate) and slow (due to surface temperature changes) drivers of precipitation change. They discuss likely future changes over land and sea and the causes of the past and projected trends and find that the increase may become clearly observable by around 2050.

    J. Clim. 31, 9641 (2018).

  7. Geophysics

    Dropping ferric iron into a low spin

    1. Brent Grocholski

    Iron located in lower-mantle bridgmanites undergoes a spin transition that could alter the seismic properties deep in Earth. Liu et al. found that ferric iron undergoes a spin transition in one of the cation sites of mantle bridgmanite at mid-mantle pressures. The completion of this now-well-constrained spin-transition pressure range roughly lines up with the point at which the relative viscosity of the lower mantle decreases while not having much impact on the seismic wave properties. These new data help us understand the dynamics and interpret the seismic picture of Earth's inaccessible mantle.

    Nat. Comm. 9, 1284 (2018).