October 11, 2006 | David F. Coppedge

Nature Potpourri

Articles of interest from Nature have been piling up in the CEH queues.  Perhaps a brief mention is better than nothing, before they fall into archive oblivion.

  • Carbon 14:  In the Sept 14 issue, there was a give & take between critics of a carbon-14-dated study and the author.  The critics pointed out, “We appreciate that Mellars’ review was restricted to radiocarbon dating, principally of bone, but it is recommended practice that multiple methods and materials should be investigated to avoid any possible pitfalls that might be associated with a single technique or sample type.”  They decried the need for “much-needed rigour to radiocarbon chronologies.”
  • Bossa Supernova:  Also in the Sept 14 issue, David Branch reported a “champagne supernova” in a star not known to go boom.  “Thermonuclear supernovae were thought to occur only when white-dwarf stars of a certain mass explode,” he said.  “The discovery of a supernova that is way over the mass limit might require a reworking of the model.”  See also the press release from Berkeley Lab.
  • Twinkle, huge star:  Showing that the best proof of a theory in science is existence, an international team said in the Sept 28 issue (pp 427-429), “Theory predicts and observations confirm that low-mass stars (like the Sun) in their early life grow by accreting gas from the surrounding material.  But for stars approx ~10 times more massive than the Sun (approx > 10 solar masses), the powerful stellar radiation is expected to inhibit accretion and thus limit the growth of their mass.  Clearly, stars with masses >10 solar masses exist, so there must be a way for them to form.”  They presented a theory based on non-spherical accretion.
  • Political science:  Environmental activists are another thorn in Big Science’s side.  In the Oct 5 issue, an Editorial began, “Not everyone’s opinion is equally valuable.”  Eco-terrorists who blow up science labs are just the most outspoken of a larger base of support.  Nature advocated dialog with these folks: “signs of paternalism or scepticism about emotional arguments will quickly alienate a section of public opinion whose views, although logically fuzzy, are very firmly held.”  They didn’t say what to do about critics of Big Science whose views are logically sound and very firmly held.
  • Hanging by a string:  The Oct 5 issue had several articles for and against string theory.  The Editors were for it, George Ellis was against it, and Geoff Brumfiel reported the war of words in several new books like Not Even Wrong and The Trouble with Physics: The Rise of String Theory, the Fall of a Science, and What Comes Next.  Ellis reviewed the latter and began, “String theorists are setting a worrying trend by downplaying the need for experimental evidence.”
  • History of science and art:  The Oct 5 issue mentioned an exhibition of the science and art of Leonardo da Vinci touring Europe.
  • Geo-lithium:  How sure are we of the science under our feet?  The Oct 5 issue had a news item beginning, “Lithium isotopes provide a fingerprint of recycled material in Earth’s upper mantle.  But this fingerprint is different from what had been expected.  So do we need to reassess our ideas about how the upper mantle evolves?”
  • Kryptonite-proof superbacteria:  The Oct 5 issue investigated how the tiny germ Deinococcus radiodurans can withstand radiation hundreds of times greater than that required to kill ‘normal’ bacteria.  The secret is in its super-fast and efficient DNA repair mechanisms.  See the Scientific American write-up on this germ.
  • Useful junk:  Two French scientists in the Oct 5 issue (pp 521-524) think junk DNA is an “evolutionary force.”  They said, “Transposable elements were long dismissed as useless, but they are emerging as major players in evolution.  Their interactions with the genome and the environment affect how genes are translated into physical traits.”  It seems odd that a major player in evolution would elude discovery this late in the game.  “But it is an open question whether the variation in genome size is indirectly associated with host population size, or whether it is directly promoted by environmental stress or by the novel environmental conditions that populations encounter when they invade a new habitat,” they said.  “The answer will bear on our understanding of, for example, how ancestral humans adapted after they migrated out of Africa.”  Seems a tall order for junk DNA to explain.
  • Give and take:  Co-evolution was the theme of two articles in the Oct. 5 issue, one by Gavin Sherlock commenting on another paper by Jensen et al.  They considered cell division, discussing the odd observation that while the genes are highly conserved (unevolved) throughout the living world, the expression of these genes is not.  This adds greatly to the complexity of theorizing how the cell cycle evolved, because now the genes and their regulators had to co-evolve; in fact, Jensen et al say, “Our current results raise the intriguing possibility that all three levels of regulation have co-evolved.”  In addition, they discuss the remarkable phenomenon called “just-in-time assembly” in which certain protein complexes only go into action when key proteins are expressed only at the point in the cycle when they are needed.
        “It is tempting to speculate on the driving force that leads to the co-evolution,” they said in this paper that, while admiring the complexity observable today, was heavy on speculation about how it got that way.  “Together, our results provide a first global view of the evolutionary dynamics of the transcriptional and post-translational regulation of a large and complex biological system,” they said in conclusion.  But how much can be inferred about evolution?  Not much: “They clearly indicate that although the same general underlying principles, namely just-in-time assembly and multi-layer regulation of functional modules, are widely conserved in eukaryotes, the detailed regulation of individual genes and proteins varies greatly and thus generally cannot be inferred from distantly related organisms.”
  • Zygote to adult:  A book review of Eric Davidson’s The Regulatory Genome by Michael Karin in the Oct. 5 issue dealt with a related problem: “All living organisms deploy similar evolutionarily conserved mechanisms to generate energy, replicate their genomes, use genetic information and synthesize basic building-blocks for their cells,” he began.  “Yet the myriad shapes and forms of both plants and animals are overwhelming in their variety and extremes.  What is even more amazing is that most plants and animals start their life as a single diploid cell (a zygote) created by the union of a sperm and an egg.  How these simple cells give rise to such complex creatures with diverse body shapes is a major preoccupation of developmental biologists.”
  • TRON revisited:  Can life live in a computer?  A German team in the Oct 5 issue investigated biological models in silico.  They recognized that this is not a field for initiatives, and that some traditional biologists are skeptical, they said, “Suspicion towards simulations should dissipate as the limitations and advantages of their application are better appreciated, opening the door to their permanent adoption in everyday research.”  Surprisingly, at the end, “By discovering design principles, identifying biological modules, and quantitatively understanding how they operate through experiments and simulations, we hope to elucidate biological function,” they said.

Readers interested in these subjects may wish to pursue the original sources.

This illustrates how the reporting here has to be selective just due to constraints of time and space.  Every week, scores of sources and articles from the scientific journals and science news outlets are perused for consideration.  For every article that gets mentioned, dozens more have to be passed over.  We hope you appreciate getting at least a daily digest of interesting and important happenings in a wide variety of subjects related to origins.

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Categories: Astronomy, Genetics

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