[LMB] Gene cleaning in real life

Matthew George matt.msg at gmail.com
Mon Nov 13 23:15:01 GMT 2017

Although needing eyeglasses is, like almost any trait we can imagine,
linked to genes, it's surprisingly not-controlled by them.  The best
explanation I've heard is that our physiologies "expect" us to spend a
great deal of time in relatively bright light, and the growth of our eyes
is actually dependent upon that condition.  Spending lots of time indoors,
where 'bright light' is much dimmer than conditions outdoors, seems to be
highly correlated with the malformations of the eyes responsible for
nearsightedness and farsightedness.

It might be possible to select for alleles that screw up that developmental
process.  Much the same way we might select for mutations which interfere
with the careful feedback our muscles and bones use to remain strong enough
to meet ordinary needs while not expending vital resources, so that we
wouldn't be affected by low gravity and wouldn't need to exercise to
maintain muscle tone.

Whether those changes would be truly adaptive in the long term is an open,
and very difficult to answer, question.

Matt G.

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