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Ch. 3 - Immortal coils

#71: Sept. - Oct. 2009 (Non-Fiction)
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Chris OConnor

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Ch. 3 - Immortal coils

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The Selfish Gene by Richard Dawkins
Ch. 3 - Immortal coils
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Dawkins wrote:A.G. Cairns-Smith has made the intriguing suggestion that our ancestors, the first replicators, may have not been organic molecules at all, but inorganic crystals—minerals, little bits of clay. Usurper or not, DNA is in undisputed charge now, unless, as I tentatively suggest in Chapter 11, a new seizure of power is now just beginning.
Did anyone else say holy shit! at this point?

Anyway, I know it's the cockroaches. Damned disgusting things! We all knew they would take over sooner or later. :slap:
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Immortal Coils is the second longest chapter in The Selfish Gene, at 27 pages coming in just under Battle of the Sexes with 28 pages. Immortal Coils is devoted to DNA, explaining, as Geo notes above, that replicating inorganic crystal may be the origin of life. DNA “consists of a pair of nucleotide chains twisted together in an elegant spiral, the 'double helix'; the 'immortal coil'.” (p23) With four letters, “DNA can be regarded as a set of instructions to make a body, written in the A, T, C, G alphabet of the nucleotides.” The 'bookcase' is the nucleus, with 46 'volumes' called chromosomes.

As a general reader, I find Dawkins' explanation of genetics simple and clear. He says “natural selection favours replicators which are good at building survival machines, genes which are skilled in the art of controlling embryonic development. … The same old processes of automatic selection between rival molecules by reason of their longevity, fecundity, and copying-fidelity, still go on..” (p25).

Here he makes a strong statement which I read as saying that genes are more real than people, that reality is a function of persistence through time. Although the term reality here is mine, Dawkins is clearly discussing objective reality with his comment that “the combination of genes which is any one individual may be short-lived, but the genes themselves are potentially very long-lived. … One gene may be regarded as a unit which survives through a large number of successive individual bodies. This is the central argument which will be developed in this chapter.”

Do you think reality is a function of persistence through time? Does this statement make sense as a genetic philosophy?

Immortal Coils has fascinating information on gene shuffling or crossing over, alleles, and the genetic unit of the cistron. He says “a gene is defined as any portion of chromosomal material which potentially lasts for enough generations to serve as a unit of natural selection... a replicator with high copy-fidelity... The shorter a genetic unit is, the longer, in generations, it is likely to live ” (p30)

Pluckily almost invoking Robin Hood, he says “Neighbouring cistrons on the same chromosome form a tightly-knit troupe of travelling companions who seldom fail to get on board the same vessel when meiosis time comes around.” (p35) Robin Hood's merry band picks up cistron loyalty, but Dawkins' nautical vision of the genetic vessel is more like Jason and the Argonauts, who left Hercules behind on an island halfway from Greece to Georgia on their trip to get the golden fleece. Of course, meiosis is once per generation, so our plucky cistron bands are long lived indeed.

Dawkins' theory of reality gives primacy to entities that last for a long time. He says “Natural selection in its most general form means the differential survival of entities. … some of the entities must be capable of surviving – in the form of copies – for a significant period of evolutionary time. Small genetic units have these properties; individuals, groups and species do not....The genes are the immortals.” (p35-6)

In a nice analogy, “chromosomes too are shuffled into oblivion, like hands of cards after they are dealt. But the cards themselves survive the shuffling. The cards are the genes. … genes are denizens of geological time. Genes are forever.” (p37)

I couldn't help thinking of Daleks (and incidentally of Dawkins' wife Lalla Ward of Dr Who fame) when he says “they are the replicators and we are their survival machines.” (p37)

Dawkins draws a fine analogy with a rowing eight, where the best squad has the best rowers working as a team. Genes are team players too, in competition with their rival alleles. He starts getting into the mathematical game theory of evolution when he asks why we get old and why there are two sexes. Great explanations.
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Robert Tulip wrote:In a nice analogy, “chromosomes too are shuffled into oblivion, like hands of cards after they are dealt. But the cards themselves survive the shuffling. The cards are the genes. … genes are denizens of geological time. Genes are forever.” (p37)

I couldn't help thinking of Daleks (and incidentally of Dawkins' wife Lalla Ward of Dr Who fame) when he says “they are the replicators and we are their survival machines.” (p37)

Dawkins draws a fine analogy with a rowing eight, where the best squad has the best rowers working as a team. Genes are team players too, in competition with their rival alleles. He starts getting into the mathematical game theory of evolution when he asks why we get old and why there are two sexes. Great explanations.
Robert, your chapter summaries are excellent.

I had forgotten that Dawkins' wife was one of the Doctor's assistants.

Anyway, this is a long chapter. Some of these concepts are complicated and I find myself re-reading some of the passages, but I do agree with Robert that Dawkins really shines in his explanations. In particular, I was fascinated by his definition of a gene because it's not as straightforward as I had imagined. Specifically, what is a single gene?

"I am using the word gene to mean a genetic unit that is small enough to last for a large number of generations and to be distributed around in the form of many copies. This is not a rigid all-or-nothing definition, but a kind of fading-out definition, like the definition of 'big' or 'old'. The more likely a length of chromosome is to be split by crossing-over, or altered by mutations of various kinds, the less it qualifies to be called a gene in the sense in which I am using the term. A cistron presumably qualifies, but so also do larger units. A dozen cistrons that may be so close to each other on a chromosome that for our purposes they constitute a single long-lived genetic unit." (pg. 32-33)

As Robert says, Dawkins frequently uses a nautical theme to analogize the gene's longevity: "As the cistrons leave one body and enter the next, as they board sperm or egg for the journey into the next generation, they are likely to find the little vessel contains their close neighbors of previous voyage, old shipmates with whom they sailed on the long odyssey from the bodies of distant ancestors. neighboring cistrons on the same chromosome form a tightly-knit troupe of traveling companions who seldom fail to get on board the same vessel when meiosis time comes around." (p. 33)

With the team player analogy, Dawkins switches to the analogy of oarsmen on a boat. If I understand Dawkins correctly, I think he's referring here to what in the business world they call "synergy," the idea that interactions between components sometimes yields results that are greater than the sum of the parts (i.e. 2+2=5). At least the concept is similar? I've often thought that many sports teams and rock bands—The Beatles for one— illustrate this mysterious synergy. "One of the qualities of a good oarsmen is teamwork, the ability to fit in and cooperate with the rest of the crew. This may be just as important as strong muscles." (pg. 39) Individually, John Lennon and Paul McCartney were extremely talented singers/songwriters, but they somehow brought out the best in each other so that the outcome of the band seemed to exceed the sum of their parts. I would say this about a lot of prog rock bands as well (i.e. Yes and Genesis come to mind.)

Regarding the question, what good is sex? I have always thought it's a mechanism to bring out the best in the species, but I guess this doesn't mesh with Dawkins' selfish gene theories. Say you have an individual who is anti-social—doesn't get along very well with others—or someone who is not very physically fit. Theoretically, these individuals are less attractive to others and each would have a more difficult time finding a mate. They are less likely to reproduce and thus their genes over time will get weeded out. The advantage of sex—the idea that each individual needs another individual to unlock his/her mating potential—would thus lead to a stronger, more thriving species. A more thriving species would be good for the individual gene too, wouldn't it?
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Amen to the excellence of Robert's summaries. Really thought provoking, Geo. Too bad I'm too tired to think!
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Did anyone else say holy shit! at this point?
Frankly this whole book is making me say holy shit. It is amazing.
The advantage of sex—the idea that each individual needs another individual to unlock his/her mating potential—would thus lead to a stronger, more thriving species. A more thriving species would be good for the individual gene too, wouldn't it?
This is a good question. I am thinking that Dawkins does not think the individual species matter that much to the gene. The gene will continue on in whatever “the survival machine” looks like. He says “Individuals are not stable things, they are fleeting”. So I think that what he is saying about sex is that while it actually in the long run harms the longevity of the individual being it does not harm the gene. A couple who have a child only pass a half of their genetic material onto their offspring. That becomes smaller and smaller over time. The gene, however, can go on and on forever. I can see why some people would find that disturbing. I think a lot of us have the idea that we will live on through our prodigies but it sounds like Dawkins is saying that that cannot happen. The individual creature will die but the genes will not.

He almost makes genes sound like parasites. They just kind of inhabit a body and when that body dies they just move on to the next. Very horror movie, science fiction. :laugh:

Something that piqued my interest was “universal qualities” of long living genes. Certainly different species adapt to their environment depending on what that environment looks like. Are there universal qualities that all species develop? Adaptability certainly is something that makes a species more likely to survive for longer periods. Would this be a gene trait? Is it possible for all species to have a universal quality?
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I happened to catch a show on the Science Channel about the genome project. One scientist (can't recall his name) said something that I found very interesting given what we're reading.

He said that it would be very easy to lengthen human life expectancy by a significant factor. All we would have to do is prevent all reproduction until a certain age, for example age 40. By doing this we would be systematically favoring the dominance of the "old age gene" and weeding out the "die young" gene at the same time.

After some period of time you would start to bump up the minimum age to reproduce and you would continue to push out life expectancy. He did affirm that he was not advocating this, simply using it as an illustration of how our behavior can impact natural selection.
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moved to ch1
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Our culture is already working in the direction of delaying conception and therefore increasing lifespan. Delaying marriage, having kids later than previous generations, and contraception all accomplish this. I gather the theory is individuals who delay having kids and die of genetic problems prior to procreating do not pass those genes on to future generations.
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I'm having a bit of a problem with the premise of this book for several reasons.

- Dawkins doesn't define a gene very well. Is it a single set of cells or is it mulitple genes working together towards some effect? He leaves this open.
- Random mixing of genes in individual sperm or egg cells means there is no guarantee that a "successful" gene will be propagated.
- Dawkins admits the interaction with the environment is not a the level of the gene, it's at the level of the individual organism.
- Given this it seems Dawkins describes gene longevity through generations as an effect of evolution, not the driving force.

(I'm just starting Chapter 4, so parked this here. Sorry, didn't keep notes to refer to specific areas of the book.)
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