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SUMMARY:How wide and how tall? Genome Wide Association Studies in debate\,
  from height to educational attainment and back - Ulrika Björkstén (Clar
 e Hall\; Sveriges Radio)
DTSTART:20190509T120000Z
DTEND:20190509T130000Z
UID:TALK123088@talks.cam.ac.uk
CONTACT:Richard Staley
DESCRIPTION:In April 2018 a study was published that claimed to have found
  evolutionary differences between human populations on different continent
 s\, with a larger selection in some populations for genes which could be l
 inked to educational attainment (Racimo et al\, _Genetics_\, 208\, 1565–
 1584). A few months later the same research group presented new results ca
 lling to question the very foundations of their own methodology (Jeremy Be
 rg et al\, BioRxiv\, 23 June 2018).\n\nIn this paper based on a chapter in
  progress I trace how claims about evolutionary differences between human 
 populations in the selection of complex traits were constructed from 2010 
 to 2018\, starting with the publication of GWAS-data linked to height by t
 he so-called GIANT-consortium in 2010 (_Nature_\, 467\, 832–838). This a
 rticle was considered a breakthrough in GWA-studies of complex human trait
 s\, finding hundreds of genetic markers correlating to height differences 
 between individuals. Although the authors carefully noted that these genet
 ic markers could not be used for predictive purposes\, but should rather b
 e regarded as indicators of genetic loci suitable for further exploration 
 of functional genetic links to height\, this set of markers was subsequent
 ly used in a study investigating evolutionary explanations to height diffe
 rences between different European populations (_Nature Genetics_\, 44\, 10
 15–1019). The article published in 2012 was hence one of the first to cl
 aim to have found active selection for a complex human trait which differe
 d between populations.\n\nAfter these two initial articles were published\
 , several years of similar research followed on ever larger datasets\, as 
 the GIANT consortium grew. With the increasing power of new datasets\, inc
 luding genetic data from hundreds of thousands of individuals\, the number
  of genetic markers that could be statistically linked to height differenc
 es between individuals also grew. These results were in their turn used as
  starting points for new studies of the evolutionary background to differe
 nces in height between different populations\, notably between southern an
 d northern Europeans. Simultaneously\, the success of the 2010-study had s
 parked a whole new field of research applying GWAS to an increasing number
  of human traits\, including one as complex and highly culturally dependen
 t as 'educational attainment'. In 2018 the field hence culminated in a stu
 dy claiming to have found an evolutionary background to differences betwee
 n human populations in the frequency of genetic markers that could be link
 ed to educational attainment. The political implications of this claim spa
 rked a controversy within the population genetics community (Novembre et a
 l\, _Genetics_\, 208\, 1351–1355) which led to a reconsideration of earl
 ier results. Comparing the GWAS-results from one data set (GIANT) to anoth
 er (UK Biobank) researchers found that the statistical link between certai
 n genetic markers and height all but disappeared. The explanation given wa
 s that the GIANT-dataset suffered from unknown population stratification. 
 This finding brought to question the methodology as such\, since it uncove
 red a hitherto underestimated sensitivity to confounding factors.\n\nInter
 estingly\, the seminal article of the field\, published in 2010\, included
  a clear warning of using GWAS-results for prediction. Instead it stated t
 hat the genetic markers found should only be used as a starting point for 
 further investigations of genetic functionality. This story hence unfolds 
 as a case study of how scientific results take on new meanings as they lea
 ve their original setting and are interpreted by other researchers and imp
 lemented as starting points for new studies.\n\nAnother aspect of this cas
 e study is that the original datasets used had a very heavy bias of northe
 rn European genetic data. Recent studies have shown that genetic markers f
 ound by GWAS in one population cannot necessarily be transferred in a mean
 ingful way to another population. This story hence also serves as a very c
 oncrete illustration of how a Eurocentric approach may skew scientific res
 ults.
LOCATION:Seminar Room 2\, Department of History and Philosophy of Science
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