An amino acid polymorphism in the couch potato gene forms the basis for climatic adaptation in Drosophila melanogaster

Most organisms are faced with dealing with seasonal variations in environmental conditions.  As winter approaches, physiological changes need to be implemented: deciduous trees drop their leaves, mammals may hibernate, and so forth.  In the case of many insects, the strategy is to move into a diapause state.  This may be in any of the life stages - pupal diapause, larval diapause etc, and in the case of Drosophila melanogaster reproductive diapause, in which ovarian activity is shut down in response to a combination of short day length and low temperature.  My interests in diapause are two-fold in origin: firstly, diapause appears to have an impact on lifespan in Drosophila, and secondly, my father identified the existence of reproductive diapause in Drosophila back in 1989.  

"Privacy is in our DNA, so we need to be honest and clear about what we are doing. We have decided not to be in Phorm because of that... The way it was proposed, the privacy issue was too strong." 

Just thought I'd plug the new release of Ubuntu Linux: Version 8.10, Intrepid Ibex.  Ubuntu Linux is the linux distribution that I use on my work laptop and three PCs at home.  In my view it's a fully featured and fully functional operating system, and well worth investigating. The press release is here.

I choose Ubuntu for a number of reasons, including ease of installation, software installation and upgrades. And of course it's open source and a free download  I'm well aware of the numerous alternative versions of Linux out there, and that some of those may better suit other users.  check out the distrowatch site for more information.   Many thanks to all the developers that together enable the distribution of so many flavours of Linux.

We've had another paper on the WRN exonuclease homologue accepted for publication.  In it we demonstrate that DmWNexo is a 3'-5' exonuclease, and describe a new EMS allele. Here's the abstract:

The premature human ageing Werner's syndrome is caused by loss or mutation of the WRN helicase/exonuclease. We have recently identified the orthologue of the WRN exonuclease in flies, DmWRNexo, encoded by the CG7670 locus, and showed very high levels of mitotic recombination in a hypomorphic PiggyBac insertional mutant. Here, we report a novel allele of CG7670 , with a point mutation resulting in the change of the conserved aspartate (229) to valine. Flies bearing this mutation show levels of mitotic recombination 20-fold higher than wild type. Molecular modelling suggests that D229 lies towards the outside of the molecule distant from the nuclease active site. We have produced recombinant protein of the D229V mutant, and assayed its nuclease activity in vitro, and compared activity with that of wild type DmWRNexo and a D162A E164A double active site mutant we have created. We show for the first time that DmWRNexo has 3′ -5′ exonuclease activity and that mutation within the presumptive active site disrupts exonuclease activity. Furthermore, we show that the D229V mutant has very limited exonuclease activity in vitro. Using Drosophila , we can therefore analyse WRN exonuclease from enzyme activity in vitro through to fly phenotype, and show that loss of exonuclease activity contributes to genome instability. 

The BBC reports that measures to prevent undesirables gaining access to the UK are to be strengthened, under measures to be introduced by our not-so-libertarian Home Secretary.

At least the plan is to announce who's on the the list of over 230 individuals considered to be a threat to the UK.   The measures  are as follows:

The British Humanist Association have teamed up with Richard Dawkins to push a message on London buses. 

It's apparently in response to previous pro-religion bus advertising (see Ariane Sherine's comment article at The Guardian). You can donate to the campaign here.   Fund raising has exceeded expectations - perhaps the campaign with run and run (round and round?).  As of 28/10/08:

Bernhard Kohl has apparently been interviewed about his slide into doping (cyclingnews.com).  The essential points make for interesting reading:

His decision to dope followed an extended period without results despite a good showing in the Dauphine Libere, a crash, and an awareness that contract negotiations for next season go on during and after the Tour d France.  He claims it was his decision to take CERA.  He complains about the press blaming riders alone for doping.  The media blame game may well be directed at the riders, and I think this raises interesting points.

Perhaps I have just taken the wrong career path in science, but I do find the reports of interesting new fossils rather exciting.  And how could I resist a paper describing a "bizarre Jurassic maniraptoran"?  It seems that hardly a week goes by without a striking fossil from China being described.  This one hit the BBC news pages, from where I linked the reconstruction of the animal below.

In the 1950s, Louis Miller conducted a number of experiments that tried to model the origin of organic compounds in a  prebiotic world.  Among these was the Miller-Urey experiment, in which a vessel containing water, methane, ammonia and hydrogen was heated and subjected to electrical discharge (simulating lightning). Diagram of the experiment (Wikipedia).  At the time, Miller reported that a number of amino acids were formed.

This brief article describes the reanalysis  of stored vials containing the outcome of one of these experiments, using material found at the University of Chicago after Miller's death.  Apparently Miller had identified five amino acids and a number of unidentified compounds in some of the experiments.

 Alfred Henry Sturtevant is another of my all time heroes of Drosophila genetics (see also Calvin Bridges).

 As an undergraduate he generated the first genetic map of any organism.  He realised the linear order and relative position of genes on a chromosome would be reflected in the frequency of genetic recombination between them. Using a set of six X-linked mutants (actually two were alleles, so there were only five markers), he assembled a 5 locus map of the X chromosome. [Sturtevant (1913) J. Exp. Biol. 14; 43-59; pdf]
• Sturtevant's discovery of inversion is important because it explains the why/how of certain genetic defects and discovery of inversion allows for its presence to be tested for