From: Anders Sandberg (asa@nada.kth.se)
Date: Fri Nov 29 2002 - 02:32:08 MST
On Thu, Nov 28, 2002 at 08:43:05PM -0500, Entropyfoe@aol.com wrote:
> I forgot to mention, Gilber's syndrome is fairly common, I have seen figures
> as high as 7% of people have this genetic variant.
> -Jay
This suggests that it does not decrease fitness much; I'm just
reading Cavlli-Sforza's _The genetics of human populations_. He
points out that the equilibrium frequency of a deleterious
dominant mutation is mu/s, where mu is the mutation rate and s is
the selection coefficient (0 means no change in fitness, 1 is
lethal). To get 7% spread for a mutation rate of ~1e-5, s=1.4e-4
i.e. Gilbert's syndrome provides a tiny disadvantage. There might
be some anti-ageing component, but I doubt it - that would likely
in historic times have made the gene have positive fitness and it
would have become even more common.
Still, it might be interesting to study the lifespans in an
animal model:
Hepatology 1984 Mar-Apr;4(2):175-9 Related Articles, Links
A nonhuman primate model of Gilbert's syndrome.
Portman OW, Roy Chowdhury J, Roy Chowdhury N, Alexander M,
Cornelius CE, Arias IM.
A Bolivian population of squirrel monkeys, Saimiri sciureus,
exhibits several features of Gilbert's syndrome in man, and is
proposed as a nonhuman primate model of the condition. The
Bolivian population was found to have higher fasting (40.6 +/-
2.7 microM; mean +/- S.E.) and postcibal (9.9 +/- 0.9 microM)
plasma unconjugated bilirubin concentrations (p less than 0.001)
than a closely related Brazilian population (fasting 5.5 +/- 0.7
microM); postcibal (2.4 +/- 0.7 microM). After intravenous
administration of [3H]bilirubin as a tracer dose or at 3.4
mumoles per kg body weight, there was delayed plasma clearance in
the Bolivian monkeys. Hepatic UDP-glucuronyl transferase activity
for bilirubin (164 +/- 25 nmoles per 30 min per gm liver) and
biliary bilirubin diglucuronide to monoglucuronide ratios (2.9
+/- 0.2) were lower in Bolivian monkeys than in Brazilians (421
+/- 36 nmoles per 30 min per gm liver--p less than 0.01 and 4.1
+/- 0.1--p less than 0.02, respectively). Hepatic cytosol
glutathione-S-transferase B activity (ligandin) levels were
similar for the two populations. After phenobarbital therapy,
fasting (11.1 +/- 0.9 microM) and postcibal (5.3 +/- 1 microM)
plasma bilirubin concentrations in Bolivian monkeys were
significantly reduced (p less than 0.001). Sulfobromophthalein
clearance was slightly slower in the Bolivian than in the
Brazilian monkeys. SGOT, lactate dehydrogenase, gamma-glutamyl
transpeptidase and alkaline phosphatase activities were not
increased in Bolivians. Fasting serum conjugated bile salt
concentrations in Bolivian monkeys were lower than that in
Brazilian monkeys (p less than 0.01).(ABSTRACT TRUNCATED AT 250
WORDS)
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