Friday, February 14, 2014

Let's shake on it!

Well, folks, as to how your research money is being spent:

Here's the Bulletin of the Week (or, at least, Day) from Nature, Heredity, not your usual source of such earth-shattering news.   Nature Heredity reports that a GWAS twin study finds no genetic evidence for handedness.*  Since GWAS is the Ptolemaic theory of our time (see yesterday's post and comments), this latest epicycle of not-to-be-questioned methodology is not just a shocker, but a confirmation (of something).  This must be at least as much so as yesterday's Big Story, that a genome sequence from a pre-Columbian US skeleton shows that Native Americans really and truly were---- descendants from Asians!

Let's shake on it--it's a big deal...isn't it?
That the handedness story made Nature was published at all, and then given such play, will certainly reinforce the idea that no 'paradigm shift' is currently needed in genomics or evolutionary biology.  This will bring comfort to hundreds of investigators and thousands of their graduate student trainees learning truth by doing their masters' work for them.  Some might have been worried that at least a few people have questioned the current ability of our science to provide definitive genetic answers to every question we might think to ask about any trait of vital societal importance.

Actually, what this study really shows, once and for all, is a fundamental fact about modern genetics:

The left hand doesn't know what the right hand is doing!**

* We add a caveat that the study suggests.  They were able to analyze a mere 3940 twins, so could only detect genomic single-SNP effects with an odds ratio of 2.0.  It could not detect sites with an OR of 1.2 or less.  The point, of course, is to provide an advance justification for anyone to propose a gargantuan meta-analysis of, say 100,000 twins, to detect the grains of sand that contribute to this vitally important trait.

** And apparently the right hand doesn't know what the right hand is doing here!  This story is in Heredity, not Nature!  Our mistake, thinking the BBC only picks up Nature/Science stories!


Manoj Samanta said...

Ken Weiss said...

Well, there have been many studies and many (probably even more!) theories on handedness. Offhand, so to speak, I think there are more important things to do, but it is an interesting question if it were to be addressed in some well-posed way, which probably most such studies have not really done. How inborn is it? How strong? How much based on some experience early on? How much based on chance during deveopment? Is there a reason why most people are right-handed? Why are other animals as handed as we--or are they?

I don't know the literature but these are good and interesting questions if addressed thoughtfully. Just genome mapping may not be the best way, unless the trait really is rather simply determined--as it seems (from the study we mentioned and what your provided) not to be. Still, one can ask the interesting question whether if the trait is strong or has some actual fitness value, isn't polygenic control enough--why should we expect only one or a few genes to control it?