
Genome-wide association analyses provides new insights into circadian rhythms - gwern
https://www.biorxiv.org/content/early/2018/04/19/303941
======
carbocation
It's interesting to me that they chose to limit the polygenic risk score to
the SNPs at the top 292 loci, rather than using all available SNPs, which has
become more common. I would guess that they chose to limit their power in
favor of ease of interpretation, but it would be interesting to understand why
they actually made their choice.

It's also a bit surprising that being a morning person was associated with
earlier age at last childbirth in women. I would have expected being a morning
person to correlate with education attainment (which I don't believe they
discussed) and therefore with later age at last childbirth (since education
generally delays the age at which people start having children).

~~~
auvrw
didn't realize this is a common method ..

the correspondence with neuroanatomy is impressive. i s'p, at that level (and
i mean, likely even at the proteomic level for those that're particularly
studied in that area), it could be easier to have results that can guide
intuition. b/c that'd surely the useful thing about these kind of results, i
imagine, off the cuff, to most people in the natural sciences: providing hints
for further research on causal mechanisms and perhaps a reasonably plausible
story or "hypothesis" to be fancy (like ketchup) about it

------
yosito
> the mean sleep timing of the 5% of individuals carrying the most
> "morningness" alleles was 25.1 minutes earlier than the 5% carrying the
> fewest

Does this mean that genetics only account for 25 minutes of difference between
when "morning people" and "night owls" sleep?

~~~
gwern
No, that just means the subset of genetics noisily estimated by this
particular method & sample can predict those extremes (ie top 5% vs bottom
5%). They don't report the full polygenic score in the paper that I see,
although they note the SNP heritability is ~10% of variance (and I assume full
heritability is a lot bigger since I do recall chronotype as being highly
genetic).

