Received: by alpheratz.cpm.aca.mmu.ac.uk id RAA13776 (8.6.9/5.3[ref pg@gmsl.co.uk] for cpm.aca.mmu.ac.uk from fmb-majordomo@mmu.ac.uk); Fri, 18 Feb 2000 17:04:22 GMT To: memetics@mmu.ac.uk Date: Fri, 18 Feb 2000 08:34:29 -0800 From: "Scott Chase" <hemidactylus@my-Deja.com> Message-ID: <BAKJGJEHPHNDOBAA@my-deja.com> X-Sent-Mail: off X-Mailer: MailCity Service Subject: RE: meaning in memetics X-Sender-Ip: 209.240.200.113 Organization: My Deja Email (http://www.my-deja.com:80) Content-Type: text/plain; charset=us-ascii Content-Language: en Content-Length: 1626 Content-Transfer-Encoding: 7bit Sender: fmb-majordomo@mmu.ac.uk Precedence: bulk Reply-To: memetics@mmu.ac.uk
--On Fri, 18 Feb 2000 07:37:09 Richard Brodie wrote: >Well, I think you're very close to understanding memetics. It is absolutely >about feedback loops. Natural selection is about feedback loops. The >question is, what persistent information store can change due to feedback? >There are several candidates. One is the gene pool. The only way we know of >for the gene population to change is through natural selection. > > That's not true. Selection is considered a *primary* process inflencing allelic frequencies in populations, especially alleles with phenotypic consequence, but genetic drift is another process which can be important in certain situations, especially if the effective population size is very small. One would assume that an allele with a deleterious effect would go to extinction due to selection, but in certain circumstances a slighty deleterious allele could drift to fixation in a population instead. One should be cognizant of both selection and drift as potential influences of allelic frequencies in a population.
At the level of amino acids and nucleotides, selection might not be all that important. In regions of a protein which aren't functionally constrained (areas not involved in an active site or important structural regions for instance), neutral drift could be more important than selection. In parts of the genome such as non-coding "junk" regions and pseudogenes and nucleotides which are degenerate due to wobble, selection might not be so important either. Scott
--== Sent via Deja.com http://www.deja.com/ ==-- Share what you know. Learn what you don't.
=============================================================== This was distributed via the memetics list associated with the Journal of Memetics - Evolutionary Models of Information Transmission For information about the journal and the list (e.g. unsubscribing) see: http://www.cpm.mmu.ac.uk/jom-emit
This archive was generated by hypermail 2b29 : Fri Feb 18 2000 - 17:04:27 GMT