[ExI] Armchair Evolutionary Psychology: Larks vs Night Owls
Lee Corbin
lcorbin at rawbw.com
Tue Mar 18 09:10:51 UTC 2008
Stuart writes
> After looking at the available evidence, I would concur with Emlyn that
> this is indeed a genetic phenomenon. The PER3 (Period homolog 3) gene
> is a transcription factor and one of perhaps about a dozen highly
> conserved circadian rhythm genes. They were first discovered in
> drosophila (fruit flies) so these genes are very basal showing up very
> early in the evolutionary history of life....
>
> "The Per3 polymorphism correlated significantly with extreme diurnal
> preference, the longer allele associating with morningness and the
> shorter allele with eveningness. The shorter allele was strongly
> associated with the delayed sleep phase syndrome patients, 75% of whom
> were homozygous."
>
> Now this is a fairly convincing demonstration that homozygousity of the
> shorter PER3 allele correlates with delayed sleep phase syndrome
> (DSPS).Now if one looks at prevalence studies for DSPS one finds that
> the prevalence is 0.17% and 0.13% in Norway and Japan respectively.
> This seems to demonstrate that night owls are a widespread phenomenon
> and there appears to be no linkage between DSPS and any particular
> ethnic group. This would suggest that there is a stable equilibrium at
> an average ~0.15% for extreme night owls and that the mutation arose
> well before the divergence of "racial" characteristics amongst humans.
What characteristics are you referring to? Race and therefore "racial
characteristics" are a scientific fallacy, as surely you realize.
> Another curious observation about DSPS is that it is of much higher
> prevalence in teenagers than in adults, estimated at over 7% and skewed
> toward males. But the ratio of DSPS equalizes between sexes during
> adulthood. [Stuart's references omitted]
All right, here is what I don't understand. If it's genetic---and evidently
it is---then how does the greater opportunities for males to "strike"
during their teenage years morph into more restraint later? Well,
perhaps I'm only confused about how to describe all this. That is,
in some small tightly-knit religious communities, the teenagers know that
they dare not give in to any late night romancing because of the awful
consequences of discovery. So it seems like cultural aspect ought to
be involved too. Any simple words of wisdom to set me straight here?
> epistasis on the part of the female heterozygotes for PER3. In response
> Damien's concerns about insufficient cultural information regarding
> sleeping and sexual arrangements in our ancestors, I would surmise that
> variations in such a basal genetic system as circadian rhythm genes,
> would predate the evolutionary split between us and chimpanzees.
Sounds like a good hypothesis, but I'd be surprised if during the
last 50,000 years some populations under different selection
pressures ended up with identical distributions of this gene. For
example, I'd predict that in Muslim countries where Sharia has
been strongly enforced for centuries, (the Owl genes in your nicely
worded explanation) might by now be on the decline. Historically,
being OO could very well have lead to greater vulnerabilities
at the hands of the authorities, and so resulted in a slight diminution
of the numbers of offspring they (and perhaps even the OL and LO
types) might have.
> Therefore the cultural details would be less relevant in this instance.
> Of course the only way to find out for sure is to look for nightowls
> among chimpanzees and find out if they are indeed sneaky fuckers.
Yes indeed.
> On a more general note, I tend to object to calling what amounts to
> completely natural genetic variations syndromes, disorders, and
> diseases. From my point of view they are simply variants. If we lived
> underground, or in one of Spike's space ships, dwarfism would be the
> norm.
Sounds very sensible to me.
> If people had complete knowledge of themselves at the genetic
> level, I am certain that practically everyone would belong and identify
> with one genetic minority group or another, irrespective of the
> biological fallacy known as "race".
This is an important point. Many people today ignorantly assume
that there is some racial difference between two of the remaining
Democratic Party candidates running for president here in the U.S.
Time and time I hear one of them being regarded as "black", as
though he were of a different "race", or were partly of a different
"race". You would not believe how widespread this fallacy is here.
It gets worse. Much worse. The New England Journal of Medicine
actually reported an investigation of differences in the effectiveness
of two types of hypertension medication in the so-called "black"
people and the so-called "white" people here in the U.S. You won't
believe this, but they even went on---surely in the full knowledge
that race is a biological fallacy (they're surely not that un-read)
---to allude to a so-called "fact" that the so-called "black" people
are more likely than the so-called "white" people to have nitric-
oxide insufficiency. (Can you believe it??)
Which of course is flat-out impossible, since race doesn't exist.
Lee
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