Received: by alpheratz.cpm.aca.mmu.ac.uk id KAA12022 (8.6.9/5.3[ref pg@gmsl.co.uk] for cpm.aca.mmu.ac.uk from fmb-majordomo@mmu.ac.uk); Wed, 15 Nov 2000 10:41:32 GMT Message-ID: <2D1C159B783DD211808A006008062D3101745B0C@inchna.stir.ac.uk> From: Vincent Campbell <v.p.campbell@stir.ac.uk> To: "'memetics@mmu.ac.uk'" <memetics@mmu.ac.uk> Subject: RE: Tests show a human side to chimps Date: Wed, 15 Nov 2000 10:39:27 -0000 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset="iso-8859-1" Sender: fmb-majordomo@mmu.ac.uk Precedence: bulk Reply-To: memetics@mmu.ac.uk
Cheers Derek, v.interesting stuff.
Vincent
> ----------
> From: Gatherer, D. (Derek)
> Reply To: memetics@mmu.ac.uk
> Sent: Wednesday, November 15, 2000 8:35 am
> To: 'memetics@mmu.ac.uk'
> Subject: RE: Tests show a human side to chimps
>
> Vincent:
> But won't the net effect of water boiling mean greater survival
> rates than non-boilers, over a long enough period of time, making it in
> the
> end a form of niche construction?
>
> Derek:
> Boiling water would certainly increase survival, especially in infants
> prone
> to die from dehydrating enteric diseases like cholera. Rogers, if I
> remember rightly, does not actually look at it from this point of view, as
> he is synchronic in his analysis methods, just taking a snapshot of what
> exists at a certain time and dissecting its structure (influence of
> Levi-Strauss??).
>
> Whether or not boiling changed the genetic composition of the population
> would depend on the effective population size (written N subscript e in
> pop
> gen). A small population losing _any_ members for _whatever_ reason will
> experience a change in its overall gene pool composition, just by random
> sampling effects, known in pop gen as 'bottlenecking' or 'founder effect'.
> That's what happened to the Yuni people in California or the Pitcairn
> Islanders. Even random accidents have serious evolutionary consequences.
> But in a larger population it doesn't apply. If cholera kills only
> non-boilers, and the population is large enough that the boiler and
> non-boiler sub-groups have the same overall allele frequency, then the
> partial adoption of the cultural trait will not affect the genetic
> constitution of the population. In a small population, sampling variation
> will mean that _any_ 2-way split of the population will produce 2 groups
> with different gene frequencies - even tossing a coin. Suppose you toss a
> coin and kill everybody who gets tails. In a population of 20 this will
> have major consequences in terms of the genetic constitution of the
> population. In a population of several million, it won't.
>
> Likewise boiling. Suppose we just kill all non-boilers. Suppose boiling
> has no inherent biological survival advantage except that we ruthless
> exterminate anyone who doesn't do it. Whether or not our terrible actions
> have an effect at the biological evolutionary level depends entirely on
> the
> population size, as above. However, regardless of the genetic
> consequences
> (or lack of them), it will have a profound cultural evolutionary effect.
> Boiling will become virtually universal.
>
> That's why genes and culture _can_ be independent replicators. Can - but
> not necessarily will, of course.
>
> Vincent:
> ..... that doesn't explain how water boiling reached that degree of
> prevalence in the
> community in the first place, or why some people took it up and not
> others.
>
> Derek:
> Health workers from Lima introduced it. That's how it arrived. They were
> profoundly puzzled about the fact that some villagers didn't take it up
> and
> others did. That's when Rogers (who was working for the WHO or UNESCO at
> the time , I think) arrived.
>
> Vincent:
> Sounds like an interesting study. I don't suppose you have a
> reference to hand do you?
>
> Derek:
> The Peruvian water boiling stuff is from the first chapter of
>
> Rogers, E.M. and Shoemaker, F.F. (1971) Communication of Innovations. A
> Cross-cultural Approach. 2nd ed. Free Press: New York.
>
> For milk drinking, the classic memetic study is:
>
> Aoki K (1991) Time required for gene frequency change in a deterministic
> model of gene-culture coevolution, with special reference to the lactose
> absorption problem.
> Theor Popul Biol 1991 Dec;40(3):354-68.
>
> Department of Anthropology, Faculty of Science, University of Tokyo,
> Japan.
>
> Abstract is
> "The time required for gene frequency change under natural selection in a
> deterministic model of gene-culture coevolution is investigated. A
> discrete
> generations model is formulated, and its continuous time approximation is
> derived. In passing to the continuous time limit, it is assumed that the
> frequency of the culturally transmitted trait does not change under
> oblique
> (between generations) transmission. The system of ordinary differential
> equations thus obtained are solved, and the dependence on the parameters
> of
> horizontal (within generations) transmission and natural selection is
> examined. The time required is found to be substantially longer when the
> determination of a phenotypic difference subject to natural selection is
> partly cultural rather than completely genetic. The predictions are
> relevant
> to the possibility of the coevolution of lactose absorbers and milk
> drinkers
> in some human populations. Alternative hypotheses are briefly discussed in
> the light of the theoretical results."
>
> and there is also quite a bit in William Durham's book, if I remember
> rightly.
>
> Durham, W.H. (1991) Coevolution: Genes, Culture and Human Diversity.
> Stanford University Press: Stanford.
>
> Durham also has an exhaustive analysis of the genetics and culture of
> malaria resistance in West Africa, which goes well beyond the rather
> desultory treatment that gets trotted out in most genetics textbooks.
> That
> is really worth a read too.
>
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This was distributed via the memetics list associated with the
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For information about the journal and the list (e.g. unsubscribing)
see: http://www.cpm.mmu.ac.uk/jom-emit
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