In this week's Science, an international team led by investigators at the UK's Medical Research Council Laboratory of Molecular Biology shows that "genetic information can be stored in and recovered from six alternative genetic polymers — xeno-nucleic acids, or XNAs, which are not found in nature. The team also shows that "specific XNAs have the capacity for Darwinian evolution and folding into defined structures," suggesting that heredity and evolution "are not limited to DNA and RNA but are likely to be emergent properties of polymers capable of information storage."
As our sister publication GenomeWeb Daily News reports, an international team "has found genetic evidence contradicting the notion that the polar bear is a relatively young and quickly evolving species." The German-led group investigated the nuclear genomes of a broad sample of polar, brown, and black bears, and write in Science that their results "highlight that multilocus genomic analyses are crucial for an accurate understanding of evolutionary history."
Elsewhere in Science this week, researchers at Japan's Riken Brain Science Institute identify the yeast transfer RNA isopentenyltransferase Mod5 as a prion protein, whose "prion conversion [regulates] the sterol biosynthetic pathway for acquired cellular resistance against antifungal agents."
Finally, in a perspective piece appearing in this week's issue, Darryl Shibataat the University of Southern California Keck School of Medicine discusses intratumor heterogeneity in a historical context, saying that "how to best reconstruct the histories written in tumor genomes is uncertain, with many challenges in developing optimal sampling schemes and algorithms." Shibataat suggests that "serial biopsies can help monitor treatment by measuring reductions in heterogeneity expected with more effective therapies."