NetNews Usenet Archive 1993 #3/NN_1993_3.iso/spool/sci/bio/4963

Internet Message Format | 1993-01-23 | 3.2 KB

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From: [e-mail] (Edwin Barkdoll)
Newsgroups: sci.bio
Subject: Re: MRNA
Message-ID: <[e-mail]>
Date: 22 Jan 93 18:20:06 GMT
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In article <[e-mail]> [e-mail] (Ken Easlon) writes:
>The particular question I'm asking, "Is it within the realm of possibility
>that a large active cell suffers degradation in performance-resilience-etc
>because of the smaller nucleus to mass ratio.

    Well, there are certain cell types which are _multinucleate_,
for example multinucelated giant cell which are very phagocytically
active, and osteoclasts which are very active in the process of bone
resorption.  Whether or not the multiple nuclei are actually involved
in transcription etc and hence might not avert the "performance
degredation" you are concerned about I have no idea.

>>Put another way: I could write a one-line program that would never
>>terminate -- it would represent an infinite amount of "computation",
>>yet only consist of one line's worth of program.  So the length of DNA
>>means nothing in that context (assuming more than just transcription
>>or similar processes).
>
>I'm afraid you've lost me here.  One of the things I'm trying to come to a
>greater understanding of is the intelligence/smarts/computing-power of a
>genetically controlled cell, or the genetically controlled processes of a
>whole organism.

    Perhaps Chris is making a distinction (or asking for a
distinction) between computational speed (throughput, total "bytes" of
information...) and diversity.  Consider a cell which produces tons of
carbonic anhydrase, which if not the fastest enzyme known certainly
in the top 10, versus a cell which produces a highly diverse set of
enzymes which are very slow.  (The enzyme is not fast per se rather
the reaction catalyzed is, but you get the point.)  Consider an active
plasma cell - it is churning out protein in prodigious quantity the
vast majority of which is all exactly the same antibody.  Is it more
or less intelligent than a [cell-of-your-choice] which is
translationally pretty inactive overall but which does produce a wider
variety of proteins?

>I suspect that a program of 750 megabytes (the human
>genome) which has been under development for several billion years probably
>represents a pretty fair chunk of intelligence no matter how you measure
>it.

    Perhaps, but no cell ever expresses all that information at
the same time or even within its lifetime, nor is each "byte" or
meaningful piece of information usually expressed as a single copy.
Which goes back to Chris's point (my interpretation of Chris's point):
What if many redundant copies are produced such that the total number
of "bytes" far exceeds that in some other more diverse but pokey cell?
What's the information being measured?

>Ken Easlon
>[e-mail]


--
Edwin Barkdoll
[e-mail]
[e-mail]