Wednesday, January 23, 2019

The UK BioBank: The Beast of Pop/Strat

Here is yet another study looking at population stratification issues related to GWAS studies and polygenic score results: Apparent latent structure within the UK Biobank sample has implications for epidemiological analysis.
They looked at geographic structure and found that the UK Biobank is subject to a lot of stratification in that regard. They looked at BMI (body mass index), household income, and educational attainment and found all of them to be subject to geographic population stratification, even with principle component analysis.  First they looked at a smaller subset of genetic data from a previous study (ALSPAC)
...we anticipate that the educational attainment of people who migrate for economic reasons differs from people who do not. Educational attainment is therefore aligned to subtle genetic differences even in this apparently geographically and ethnically homogenous population and this is co-incident with axes of ancestry.
They move on to the beast, the UK Biobank:

Monday, January 14, 2019

Britain's Private Schools Makes a Point About Population Stratification

This article about the British private school system is not directly related to genetics, but goes to a point I've made earlier about genetic studies of "Educational Attainment" and how they will inevitably be filled with false positives related to population stratification.  Let me start with a quote from the article:
What particularly defines British private education is its extreme social exclusivity. Only about 6% of the UK’s school population attend such schools, and the families accessing private education are highly concentrated among the affluent. 
So we have a closed off group that has better access to higher educational opportunities, and of course there is a big payoff for them as we can see here:

Wednesday, January 2, 2019

Copy of my Review of Robert Plomin's "Blueprint"

 I'm told that my review of Robert Plomin's "Blueprint" in Free Associations is sometimes difficult to download on tablets and phone, so I will add a copy of it here:

Biogenetic Overreach by Steve Pittelli 



Blueprint: How DNA Makes Us What We Are (MIT Press, 2018) is the latest book by genetics researcher and author, Robert Plomin. It begins with discussions about twin and adoption studies, an area where Dr. Plomin has extensive experience as a researcher. This serves as a springboard for Plomin to discuss DNA research, particularly “polygenic scores,” for which he possesses an almost evangelical zeal. Mixing this with his own research anecdotes and theories about a self-described “DNA Revolution,” Plomin’s meandering narrative is, at times, difficult to follow and has a utopian feel. 

As Plomin acknowledges, much of the early DNA research related to psychological traits (and most traits in general) failed to find specific genes related to the trait in question. When such genes were found, the experiments were never replicated, creating a “replication crisis” in the field. In Dr. Plomin’s view, this crisis was solved by the larger datasets now available and the polygenic score, which “predicts” the likelihood of particular traits by tallying up the number of genetic variants a person has that have been shown to correspond in some way to particular traits. I would suggest that this is a significant lowering of the bar for replication and does not eliminate the crisis. 

Genes for Ice Cream Flavor preference...

Yes, the bar gets lowered once again as it approaches a Coke vs. Pepsi gene.  This time we have a "study" that purports to find genes for a preference for chocolate vs. vanilla ice cream (and strawberry, of course).  I know, you are thinking I'm making this up, so here it is.  I'm pretty sure, back in the day, I considered using exactly this possibility to mock these studies, but opted on "finding raisins to be tasty."  I'll get a little bit into the study, but first, let me ask anyone reading this to try to catch yourself in that moment between when something absurd was stated and when you convince yourself that it is somehow valid because, you know, it's science and all.  I like to call that the "Emperor has no clothes!" moment.  Maybe that moment has already passed you by, so try, really try, to remember how you felt in those few seconds before you had to tuck it away.  That moment is important.  It's the brief time when one can see, no matter how much they've been inundated with "scientific" pronouncements to the contrary, that this entire field of study might just have a kind of absurdity to it.
Can't go there?  Well, then you have to believe that there are genetic variants for preferring chocolate or strawberry ice cream over vanilla.  Lot's of them, in fact.  Or you have to explain why this study is not valid and other GWAS studies are.  Let's go through this important study: