kmgopinathan@violet.waterloo.edu (Krishna Gopinathan) (04/01/88)
--> Cross-posted to sci.bio <--
In article <6107@watdragon.waterloo.edu> (posted in sci.psychology)
I had written:
"... Can the existence of common psychological phenomena be linked to
an evolutionary cause? For example, did the Oedipus complex give the
young a better chance of survival? Or are they cases of a creature
(man) being thrown into an environment for which it is not suited?"
I later realized that this is related to current topics of discussion
in sci.bio, so I am cross-posting the crux of my article.
/ / o /
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Krishna Gopinathan kmgopina@water.bitnet
Dept. of Computer Science kmgopinathan@violet.waterloo.edu
University of Waterloo kmgopinathan@violet.waterloo.netnorth
Waterloo, Ontario {uunet,utzoo,ubc-vision}!watmath!violet!kmgopinathan
"A Cray is so fast it can finish an infinite loop in 3 minutes."
-- P. A. Buhrgcf@actnyc.UUCP (Gordon Fitch) (04/01/88)
In article <1085@bingvaxu.cc.binghamton.edu> vu0112@bingvaxu.cc.binghamton.edu (Cliff Joslyn) writes: >In article <6107@watdragon.waterloo.edu> kmgopinathan@violet.waterloo.edu (Krishna Gopinathan) writes: >>If we model evolution as an incredibly long tournament of genes (mixed >>n-tuples style), with mutations thrown in to make it interesting, then >>the existence of almost every human genetic characteristic can be >>explained by the survival advantage it gave to evolving man. > >Well, it depends on how many mutations are neutral. Selection preserves >both favorable and neutral mutations. I would think that there would be almost no neutral mutations at all. If a mutation were otherwise neutral, i.e. noise, it would take up room in limited genetic space (it must be limited, or "higher" species would have indefinitely many genes.) So "neutral" genes would be at least moderately negative when the cost of storing and processing the information was thrown in, and would be eliminated before long. At least, this is what the system administrators force me to do to my precious files.
kmgopinathan@violet.waterloo.edu (Krishna Gopinathan) (04/02/88)
--> Cross-posted to sci.bio <-- In article <1085@bingvaxu.cc.binghamton.edu> (in sci.psychology) Cliff Joslyn writes: >In article <6107@watdragon.waterloo.edu> Krishna Gopinathan writes: >>If we model evolution as an incredibly long tournament of genes (mixed >>n-tuples style), with mutations thrown in to make it interesting, then >>the existence of almost every human genetic characteristic can be >>explained by the survival advantage it gave to evolving man. >Well, it depends on how many mutations are neutral. Selection preserves >both favorable and neutral mutations. I think that statement has to be qualified. Selection will not preserve neutral mutations in the presence of favorable mutations. (example: the non-survival of Neanderthal man.) I understand your point though, and I think an example of that is eye colour, where no colour really has an advantage, and all except one are presumably mutations. >>My question is: Can the existence of common psychological phenomena be >>linked to an evolutionary cause? >Of course. All normal humans talk, think, sing, etc. All psychological >phenomena, all of biological origin. >>For example, did the Oedipus complex >>give the young a better chance of survival? >Assuming you believe in the complex, probably. Unless it is neutral. Questions, then: (1) Why do you or don't you "believe" in the Oedipus complex? (I didn't realize it was a matter of belief.) (2) If it did provide an survival advantage, how did it do so? / / / / / o / / / / / < )---, , / | / --. / | / / / / | / / _/ \/ /__/ __/___'_/ /_ Krishna Gopinathan kmgopina@water.bitnet Dept. of Computer Science kmgopinathan@violet.waterloo.edu University of Waterloo kmgopinathan@violet.waterloo.netnorth Waterloo, Ontario {uunet,utzoo,ubc-vision}!watmath!violet!kmgopinathan
randolph%cognito@Sun.COM (Randolph Fritz) (04/02/88)
Gordon Fitch (gcf@actnyc.UUCP) writes:
I would think that there would be almost no neutral mutations at all.
If a mutation were otherwise neutral, i.e. noise, it would take up
room in limited genetic space (it must be limited, or "higher" species
would have indefinitely many genes.) So "neutral" genes would be at
least moderately negative when the cost of storing and processing
the information was thrown in, and would be eliminated before long.
At least, this is what the system administrators force me to do to
my precious files.
Genetic space isn't limited; most of an organism's DNA is never
expressed. A good bit of it doesn't code for anything. Apparently,
rather than a large file system, an organism's genetic complement may
be better likened to a huge program library in which are stored vast
amounts of code used by the organism's ancestors. Every so often,
evolution re-uses a routine, or recycles the space occupied by an old
routine.
__Randolph Fritz, randolph@sun.com; sun!randolphpell@boulder.Colorado.EDU (Anthony Pelletier) (04/03/88)
In article <48002@sun.uucp> randolph@sun.UUCP (Randolph Fritz) writes: >Genetic space isn't limited; most of an organism's DNA is never >expressed. A good bit of it doesn't code for anything. Apparently, >__Randolph Fritz, randolph@sun.com; sun!randolph I think this needs to be qualified a bit. If we are talking about vertibrates (indeed, most eukariotes), you are quite correct. In the case of bacteria, where part of survival success is being able to reproduce rapidly, an estimate of 90% would be close for how much of the linear coding capacity is used. In the case of viruses, some actually use both strands for short stretches and alternate coding frames in a givin region. For organisms such as these, it is clear that selection to conserve space is strong. Before you have way to replicate from many origins, a way to keep a large genome organized and a great method for separating large daughter chromosome, smaller is much better. -tony
vu0112@bingvaxu.cc.binghamton.edu (Cliff Joslyn) (04/03/88)
In article <764@actnyc.UUCP> gcf@actnyc.UUCP (Gordon Fitch) writes: >I would think that there would be almost no neutral mutations at all. >If a mutation were otherwise neutral, i.e. noise, it would take up >room in limited genetic space (it must be limited, or "higher" species >would have indefinitely many genes.) So "neutral" genes would be at >least moderately negative when the cost of storing and processing >the information was thrown in, and would be eliminated before long. >At least, this is what the system administrators force me to do to >my precious files. Interesting argument. I have no idea if it makes sense in a genetic context. Any biologists care to reply? O----------------------------------------------------------------------> | Cliff Joslyn, Cybernetician at Large (now amateur) | Systems Science Department, SUNY Binghamton, New York | vu0112@bingvaxu.cc.binghamton.edu V All the world is biscuit shaped. . .
vu0112@bingvaxu.cc.binghamton.edu (Cliff Joslyn) (04/03/88)
In article <6169@watdragon.waterloo.edu> kmgopinathan@violet.waterloo.edu (Krishna Gopinathan) writes: >>>For example, did the Oedipus complex >>>give the young a better chance of survival? > >>Assuming you believe in the complex, probably. Unless it is neutral. > >Questions, then: >(1) Why do you or don't you "believe" in the Oedipus complex? I have no idea. You brought it up. I was merely completing my argument based on your premises. > (I didn't realize it was a matter of belief.) It is to the extent that all knowledge is a matter of belief. Certainly I believe everything I know. And I bet there are plenty of people who don't believe in the Oedipus complex. >(2) If it did provide an survival advantage, how did it do so? I have no idea. O----------------------------------------------------------------------> | Cliff Joslyn, Cybernetician at Large (now amateur) | Systems Science Department, SUNY Binghamton, New York | vu0112@bingvaxu.cc.binghamton.edu V All the world is biscuit shaped. . .
eddy@boulder.Colorado.EDU (Sean Eddy) (04/03/88)
>In article <764@actnyc.UUCP> gcf@actnyc.UUCP (Gordon Fitch) writes: >>I would think that there would be almost no neutral mutations at all. >>If a mutation were otherwise neutral, i.e. noise, it would take up >>room in limited genetic space (it must be limited, or "higher" species >>would have indefinitely many genes.) So "neutral" genes would be at >>least moderately negative when the cost of storing and processing >>the information was thrown in, and would be eliminated before long. Two comments: 1) You assume that any mutation adds to the amount of information that must be stored. In fact, many mutations are deletions or substitutions of existing information. 2) You assume that space is limiting in a genome. In fact, this does not seem to be so for higher organisms, which carry much more DNA than necessary. An argument can be made that the number of essential genes is limited (because of mutation rate) but absolute genome size is not. Neutral mutations should exist. For a trivial example, consider a three-base codon in a protein coding gene. The sequence of this codon is GGA, which is translated as a glycine in the protein. Because the genetic code is degenerate (as are many geneticists), glycine can also be encoded by GGG, GGU, or GGC; i.e., mutations at the third position of the codon are "silent" and thus neutral. (To a first approximation. Translational context effect buffs need not flame, please.) - Sean Eddy - Molecular/Cellular/Developmental Biology; U. of Colorado at Boulder - eddy@boulder.colorado.EDU !{hao,nbires}!boulder!eddy - - "Love is a perky elf dancing a merry little jig and then suddenly - he turns on you with a miniature machine gun." - - Kierkegaard (well, Matt Groening actually)
pan@well.UUCP (Philip Nicholls) (04/11/88)
>> > >I would think that there would be almost no neutral mutations at all. >If a mutation were otherwise neutral, i.e. noise, it would take up >room in limited genetic space (it must be limited, or "higher" species >would have indefinitely many genes.) So "neutral" genes would be at >least moderately negative when the cost of storing and processing >the information was thrown in, and would be eliminated before long. >At least, this is what the system administrators force me to do to >my precious files. Unlike the codes in a program, genetic information has a built-in "wobble" factor on several levels. The triplet codes of nucleotides are redundant, i.e., several sequences code for the same amino acid. Often, it is the third base in the sequence that varies for one amino acid, as if it is perhaps less critical than the first two. On another level, the tertiary structure of proteins is actual determined by a small number of the amino acids in it. Thus it is these amino acids, plus those in the active site (if the protein is an enzyme) that are critical. The rest can vary and it has been suggested that they do, and in a somewhat regular, clockwise fashion. These neutral mutations accumulate over time and can give an indication of phyletic distance between organisms. By the way, I have not posted or read this group much, so if I am giving an answer that sounds patronizing, I apologize in advance and will try not to do so in the future. References (for neutral mutations): King JL and Jukes TH "Non-Darwinian Evolution" Science 164:788-798. (1969) Jukes, TH "Some recent advances in studies of the transcription of the genetic message," Adv Bio Med Phys 9:1-9 (1963) -- "To ask a question, you must first know most of the answer." - Robert Sheckley pan@well.UUCP (you figure out how to get their).
c60c-5aa@web8h.berkeley.edu (04/16/88)
A hidden and, I think, unwarrented assumption in a lot of the postings about genetics, especially the genetics of psychology, lately is that <behavior X> represents a trait in even remotely the same way that, say, blue eyes do. I'm not arguing that a lot of human behavior isn't genetically determined; not at all. My point is more subtle. Is something like "the Oedipus complex" a trait? It seems to be that it may be a side effect of a lot of traits, something built into the design of a pretty complex, interacting system. Maybe what is genetic- ally determined is that (a) a child tends to identify itself with the same-sex parent, and (b) a child learns to recognize that it is not the same person as its parent, and (c) it wants what it sees others enjoying. I'm a geneticist, not a psychologist, and not the person to dissect the psychology involved; rather, my point is that selecting for or against the Oedipus complex may not be at all a meaningful idea. You might have to remodel the whole system to get rid of it. Think of a human's genetic programming as a huge C program. It's pretty easy to fine-tune and tinker. Producing whole chunks of new code by copying and then modifying sections isn't too hard. But some changes require comprehensive rewriting, and just aren't likely to occur (neither the programmer nor the species has the time!). Before speculating on the evolutionary value of an observed phenotype, it is worthwhile, if one can, to make sure that it is not a side effect of some other, obviously selective phenotype. The black hair of Negro humans may be adaptive in some way--but it's much more likely that it is a side effect of selection for black *skin*. This seems like an especial danger in psychological genetics, where we really don't know what is primary and what isn't. Mary Kuhner genetics graduate student, UC Berkeley (but my opinions are my own)
c60c-5aa@web8h.berkeley.edu (04/16/88)
A hidden and, I think, unwarrented assumption in a lot of the postings about genetics, especially the genetics of psychology, lately is that <behavior X> represents a trait in even remotely the same way that, say, blue eyes do. I'm not arguing that a lot of human behavior isn't genetically determined; not at all. My point is more subtle. Is something like "the Oedipus complex" a trait? It seems to be that it may be a side effect of a lot of traits, something built into the design of a pretty complex, interacting system. Maybe what is genetic- ally determined is that (a) a child tends to identify itself with the same-sex parent, and (b) a child learns to recognize that it is not the same person as its parent, and (c) it wants what it sees others enjoying. I'm a geneticist, not a psychologist, and not the person to dissect the psychology involved; rather, my point is that selecting for or against the Oedipus complex may not be at all a meaningful idea. You might have to remodel the whole system to get rid of it. Think of a human's genetic programming as a huge C program. It's pretty easy to fine-tune and tinker. Producing whole chunks of new code by copying and then modifying sections isn't too hard. But some changes require comprehensive rewriting, and just aren't likely to occur (neither the programmer nor the species has the time!). Before speculating on the evolutionary value of an observed phenotype, it is worthwhile, if one can, to make sure that it is not a side effect of some other, obviously selective phenotype. The black hair of Negro humans may be adaptive in some way--but it's much more likely that it is a side effect of selection for black *skin*. This seems like an especial danger in psychological genetics, where we really don't know what is primary and what isn't. Mary Kuhner genetics graduate student, UC Berkeley (but my opinions are my own