Date: Wed, 28 Jul 1999 10:12:36 +0200
From: "Gatherer, D. (Derek)" <D.Gatherer@organon.nhe.akzonobel.nl>
Subject: RE: Terminology and Quantification
To: "'memetics@mmu.ac.uk'" <memetics@mmu.ac.uk>
Mark:
Phenogenotype.
I wonder how far this term will go.
Derek:
Well it's been going since about 1973 (I think), certainly since 1981.......
Mark: (re: Laland, Odling-Smee & Feldman)
They have not gone into any detail about any mechanism
of genotype change.
Derek:
It would be by selective pressure, presumably.
Mark:
They simply bring up a few points about environmental
change, find this difficult to understand and conclude phenotypes change
genotypes.
Derek:
No, I don't think so. They're emphasising that the niche which can be
constructed (perhaps memetically in 'higher' organisms, genetically in
'lower' ones) by the organism, can then become a powerful selective pressure
at the genetic level.
For instance, I'll give you a well worked out example. Humans have
(memetically) constructed city niches. Cities need water supplies (memetic
niche construction again). That niche is a perfect breeding ground for
cholera (environment imposes selective pressure). Cholera resistance in the
form of the cystic fibrosis deltaF508 allele has reached a prevalence of
some 16% or so in western European populations. So there you have it:
culturally contructed niches ahve demonstrable genetic effects via selective
pressure.
Mark:
If I
think
about the probability distribution that 'the way I make my bed' changes my
gametes, it seems negligible.
Derek:
Yes, but that's a bad example. To pursue the bed theme, he number of
partners you choose to have (memetic) will cetainly expose you to selective
pressures which will determine whether or not you pass on any genes.
Mark:
I prefer to stick with the foundational work on information processing by
von
Neumann. He suggested a simple model for information processing: genotype +
ribotype produces phenotype. The genotype contains source information. The
ribotype transports the information to construction areas where materials
are
assembled and a phenotype is produced. Causality is straightforward.
Information is transported from the genotype to the phenotype via temporary
ribotypes. It is provides a excellent model for artificial intelligence,
computer science, genetics and other systems.
Derek:
An obsolete system. There is no ribotype.
Mark:
The Gatherer-meme lends itself to the phenogenotype notion.
Derek:
I wasn't advocating it as much as just pointing out that the only accepted
definition of fitness in memetics is within the Cavaliian tradition.
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