• Every victim of variant CJD to date, with one possible exception, has had a methionine residue at position 129 of their native prion protein and mouse models support the hypothesis that this is a susceptibility locus. Another common variant is valine, and V-129 homozygotes or V/M heterozygotes, whether mice or men, are asymptomatic. Now Asante and coworkers (doi: 10.1073/pnas.0604292103) report animal studies suggesting that V129 (hetero- or homozygous) may confer resistance to primary cross-species infection but not to intraspecies transmission. Kuru, another suspected prion disease and one dominated by intraspecies transmission (cannibalism), was recently reported in The Lancet by Collinge and coworkers to have up to 56-year incubation time (doi: 10.1016/S0140-6736(06)68930-7). Valine may make you more confident to eat burgers but, if these results hold up, you should still refrain from eating people. Asante and co also note that the source of prion and your genotype may result in one of several different pathologies, only a few of which have been seen in humans yet. Anyone planning a long retirement should consider that the ones observed in humans are the early-onset or aggressive ones in the models.
• The chance of a boy growing up to be gay increases by a third for every older brother he has. Bogaert shows (doi: 10.1073/pnas.0511152103) that this is a prenatal thing - contra Freud and his ilk, it is the number of male occupants of your mother's womb before you that have this influence, not the number of older boys barging around the family home shouting and bullying and making you want to stay in your room writing your own poetry. Stepbrothers don't contribute to the effect, no matter how boisterous or poetry-inducing, but prodigals i.e. full or half-brothers raised separately do. Puts and co discuss Bogaert's paper in a good PNAS commentary (doi: 10.1073/pnas.0604102103) that provides a context and mentions some of the bewildering, confounding complexities (having older brothers seems to reduce a boy's birthweight compared to having older sisters, although the placenta is heavier in turn; being left-handed makes a boy slightly more likely to be gay but also reduces the correlation between homosexuality and having older brothers).
• Vetsigian and coworkers (eminently eminent Carl Woese is a midfield author) describe their theoretical and computational work on how the genetic code formed (doi: 10.1073/pnas.0603780103) in actionable terms - "reductionistic fallacies" are outed, "unthinkable notions" are finally "considered seriously", a contrary working model is characterized and capitalized as "Doctrine". Underneath the opinionated ranting and preachy holism is some neat biology and interesting thinking. They believe that reticulate evolution may have applied in the "network" of early organisms that were, jointly and unconsciously, reaching a consensus on the genetic code billions of years ago. This was a time, they say, of "statistical proteins" (Woese has been talking about these since the sixties) in which nucleic acids encodes families of proteins due to the ambiguity of the as-yet-unfixed genetic code, this being not so much undesirable fuzziness as admirable variety. To me it looks a bit like the quasispecies concept in viruses and phage; in fact, it is in quasispecies (and endosymbionts) that reticulate evolution and admirable fuzziness are demonstrable. Vetsigian and co reckon that life at that post-chemical pre-biological time when the the genetic code was being disambiguated was similarly integrated, or suffused with oneness, or communal ,or whatever (often politically-) loaded term is appropriate. They're not completely smart though: ""Survival of the fittest’" literally implies that there can only be one winner from the forces of selection" (er, no, it doesn't - it was The Kurgan who said there can be only one, not The Darwin). But this nutshell version of their hypothesis is thought-provoking:

  "[W]e may speculate that the emergence of life should best be viewed in three phases, distinguished by the nature of their evolutionary dynamics. In the first phase, treated in the present article, life was very robust to ambiguity, but there was no fully unified innovation-sharing protocol. The ambiguity in this stage led inexorably to a dynamic from which a universal and optimized innovation-sharing protocol emerged, through a cooperative mechanism. In the second phase, the community rapidly developed complexity through the frictionless exchange of novelty enabled by the genetic code, a dynamic we recognize to be patently Lamarckian. With the increasing level of complexity there arose necessarily a lower tolerance of ambiguity, leading finally to a transition to a state wherein communal dynamics had to be suppressed and refinement superseded innovation. This Darwinian transition led to the third phase, which was dominated by vertical descent and characterized by the slow and tempered accumulation of complexity."

  and their conclusion is quotable and briskly falsifiable:

  Evolution of the genetic code, translation, and cellular organization itself follows a dynamic whose mode is, if anything, Lamarckian.

• Ohta and Flajnick claim (doi: 10.1073/pnas.0601407103) that IgD, a "bane to immunology students since its discovery >40 years ago", is actually as primordial and deep-rooted as ubiquitous IgM and has been "preserved as a flexible locus over evolutionary time to complement steadfast IgM". They are appealingly anthropomorphic: "Thus, it is our impression that this [IgD] is the locus that evolution "‘tinkers with,"’ perhaps using IgD/W for multiple functions at different stages of phylogeny". This reminds me a little of palaeoanthropology: great swathes of theory built around a few selective finds (a partial skull here and tools but no remains there, an IgW locus there but orthologous functions omitted here), constantly revised as the picture becomes clearer. So I expect this story will change again.
• With a title like "Theories and measures of consciousness: An extended framework", Seth and coworkers' paper (doi: 10.1073/pnas.0604347103) is threateningly theoretical and would annoy the hell out of Woese The Holist but it's actually quite measured and interesting. As an aside, I note that the last of their 13 Features of Consciousness That Require Theoretical Explanation is "Consciousness is a necessary aspect of decision making and adaptive planning.", a claim with important corollaries for work like that recently reported by Mulcahy and Call!
• Textbooks on evolution always have a bit about predator-prey coevolution, usually evinced by antelopes get faster so cheetahs get faster so antelopes get faster so…and the "evolutionary arms race" leads through a series of alternating population booms and crashes to complex bodies and behaviours. Meyer and coworkers have a paper in PNAS (doi: 10.1073/pnas.0600434103) demonstrating the changes in gene frequences in the prey half of this relationship, using not cheetahs and antelopes (or birds and butterflies, or mosquitos and DDT-wielding humans) but rotifers and Chlorella. They show just how rapid these changes can be under selection and they do it with naturally-arising mutations in handy tubes (cheetahs are less portable).

I suppose this is a sort of mini one-man carnival. Might do this regularly.