The Selfish Gene

[Roman]

In this sense the ant colony could be viewed as a single organism, as most ants are clones and carry 100% compliment of DNA. Perhaps not unlike the cells that are shed from our skin to protect the rest of the body...

Wrong.
They're haplo-diploid. Their sex determination system is based not on an X-Y chromosome, but the number of pairs of chromosomes. All the females have 2n, while the males have 1n. This means that unfertilized eggs laid become males, while fertilized eggs become females. While this doesn't equal 100% relatedness between individuals in a colony, workers are full sisters, even more so than us mammals- they share 3/4 their genetic material, as opposed to 1/2.

Not necessarily. They are merely genes that do not die ie get reproduced.

Well, given the common set of assumptions that evolutionary geneticists make, these two statements are near equivocal for the vast majority of cases.

The ant "sacrificed" itself. The gene did not. The choice, such as it is, is made by the ant. To the gene there is no difference.

But that choice would have been impossible to arrive at without those genes. Genes seem to have more direct action on behaviors when there are fewer layers of action between environment and behavior. Us humans are practically black boxes when it comes to environmental stimuli and our responses. Prokaryotes, on the other hand, literally have their behavior controlle by the surrounding environment with ROSE riboswitches. These riboswitches function as thermometers, where heat shock proteins are translated when the mRNAs melt enough to allow RNA pol access.

 

[S.A.M.]

HSP regulate all gene silencing. But still, you cannot say "the gene did it".

I have the same problem with memetics as an analogy of genetics. It smells like pseudoscience to me.

 

[Roman]

HSP regulate all gene silencing. But still, you cannot say "the gene did it".

If the gene wasn't there to be regulated...?

 

[S.A.M.]

If the gene wasn't there to be regulated...?

It wouldn't be. Same as if there were no HSP to bind with chromatin, all genes would be on.

 

[Roman]

It wouldn't be. Same as if there were no HSP to bind with chromatin, all genes would be on.

Here's the definition of gene from my introductory molecular bio textbook:

gene The basic unit of heredity. A complete chromosomal segment responsible for making a functional product. Three essential features of a gene are: the expression of a product, the requirement that it be functional, and the inclusion of both coding and regulatory regions.


Is this the same definition of gene you're using, or something else?

 

[S.A.M.]

Here's the definition of gene from my introductory molecular bio textbook:

gene The basic unit of heredity. A complete chromosomal segment responsible for making a functional product. Three essential features of a gene are: the expression of a product, the requirement that it be functional, and the inclusion of both coding and regulatory regions.


Is this the same definition of gene you're using, or something else?

I prefer Lodish:

In molecular terms, a gene commonly is defined as the entire nucleic acid sequence that is necessary for the synthesis of a functional polypeptide. According to this definition, a gene includes more than the nucleotides encoding the amino acid sequence of a protein, referred to as the coding region. A gene also includes all the DNA sequences required for synthesis of a particular RNA transcript. In some prokaryotic genes, DNA sequences controlling the initiation of transcription by RNA polymerase can lie thousands of base pairs from the coding region. In eukaryotic genes, transcription-control regions known as enhancers can lie 50 kb or more from the coding region. Other critical noncoding regions in eukaryotic genes are the sequences that specify 3′ cleavage and polyadenylation [poly(A) sites] and splicing of primary RNA transcripts. Mutations in these RNAprocessing signals prevent expression of a functional mRNA and thus of the encoded polypeptide.

http://www.ncbi.nlm.nih.gov/books/bv.fcgi?&rid=mcb.section.2147

 

[Roman]

So... which part of the expression of genes on behavior are you having problems with?

Did you know there are two populations of a migratory bird species in Europe, that when crossbred, migrate the wrong direction and die?

The ones that live in western europe fly south over the straits of ribralter, while the ones in eastern europe fly over the middle east. Both winter in sub-saharan africa. When bred, their offspring get a muddled set of genes that tells them to fly right over the Mediterranean and the Sahara, which of course, kills them.

Now, what is making that bird do that? Most biologists would posit that his genes, the hereditary material, that he has, causes that behavior. Furthermore, most of those biologists would say that it is due to a particular combination of bases in certain strands of DNA. I say most, because you don't seem to agree that genes determine behavior.

 

[James R]

SAM:

[A gene] is not identified with a DNA molecule [by Dawkins]

Then we're not talking about genes are we? Like I said, misrepresentation of concepts.

Yes, Dawkins is talking about genes. He explains this very carefully. He is not talking about particular strands of DNA in terms of a precise molecular-biological definition of the term "gene" such as the ones you have quoted above. His book is written for a general audience.

When somebody talks about a "gene for left-handedness", you'll be hard pressed to find a single piece of contiguous DNA that codes for that trait and nothing else. So, does that mean that genetic factors do not contribute to left-handedness? Clearly not. What it means is that right now we can't point to a nice neat strand of DNA and say "That's the left-handedness gene".

Similarly, you asked:

What genes code for altruism?

You seem to want an answer such as "the 478th - 57,892nd codons on the 13th chromosome". But genes don't work like that. You claim to know about this stuff, yet can't seem to distinguish a high-level explanation and usage of the term "gene" from a very specific molecular-biological explanation.

 

[iceaura]

The ant "sacrificed" itself. The gene did not. The choice, such as it is, is made by the ant. To the gene there is no difference.

The ant did not "choose" to sacrifice itself. Neither did the gene. If you want to anthropomorphize like that, instead of using the words in context for their established meaning in context, you would say the gene(s) sacrificed the ant.

Yeah, because behaviour is a multi-faceted organic response, not the product of a gene expression

Those are not mutually exclusive. Consider the multifaceted organic response of the product of a gene expression .

I've read the book, (Q), I simply disagree with its premise

You have mistaken its premise, almost completely. And since your mistake is common enough and classic enough to be dealt with specifically in the book, and in other books, and in any good genetics or evolutionary biology class, it's worth considering exactly how it came to be made.

It confuses a hell of a lot of people who have no idea what genes are or what they do. Just read the thread and you'll know what I mean.

That is something that has interested me for many years now. The basis of Darwinian evolutionary theory, the modern theory based on the mechanism discovered in the 1950s, appears to be extraordinarily difficult to grasp. Why is that ?

 

[Michael]

Do we all agree from first principals every emotion, action, thought, intuition, idea and feeling is based on chemical reactions?

Do we all agree?

 

[iceaura]

Do we all agree from first principals every emotion, action, thought, intuition, idea and feeling is based on chemical reactions?

That is the substrate of one of the levels of pattern involved, yes.

What do you mean by "based on" ?

 

[Michael]

That is the substrate of one of the levels of pattern involved, yes.

By based on I mean, every emotion, intuition, feeling, idea, memory, is at a fundamental level a product of chemical reactions - purely physical phenomena.

 

[Michael]

Agreed?

 

[sniffy]

But for everyone to accept such a principle. Well it would mean that the religioun subforum on this science forum would cease to have any relevance. Humans just another, albeit large brained and highly successful in the survival stakes, dumb animal.... why all hell will let loose if any of this ever gets out.

 

[Techne]

By based on I mean, every emotion, intuition, feeling, idea, memory, is at a fundamental level a product of chemical reactions - purely physical phenomena.

The nature of purely physical phenomena can be debated. Are elementary particles just mass and/or spin and/or charge? What about elemental proto-experiences (PEs) as phenomenal aspects that are properties of these elementary particles (quantum mechanically superimposed)?

 

[S.A.M.]

When somebody talks about a "gene for left-handedness", you'll be hard pressed to find a single piece of contiguous DNA that codes for that trait and nothing else. So, does that mean that genetic factors do not contribute to left-handedness? Clearly not. What it means is that right now we can't point to a nice neat strand of DNA and say "That's the left-handedness gene".

Exactly. Which is why the selfish gene theory does not work for me. There is no one gene that can achieve complex behaviour. It requires not only multiple genes but also environmental cues that stimulate or suppress expression of those genes to eventually present a phenotype.

So... which part of the expression of genes on behavior are you having problems with?

Did you know there are two populations of a migratory bird species in Europe, that when crossbred, migrate the wrong direction and die?

The ones that live in western europe fly south over the straits of ribralter, while the ones in eastern europe fly over the middle east. Both winter in sub-saharan africa. When bred, their offspring get a muddled set of genes that tells them to fly right over the Mediterranean and the Sahara, which of course, kills them.

Now, what is making that bird do that? Most biologists would posit that his genes, the hereditary material, that he has, causes that behavior. Furthermore, most of those biologists would say that it is due to a particular combination of bases in certain strands of DNA. I say most, because you don't seem to agree that genes determine behavior.

I think the fact that if they migrate in the wrong direction, they die is sufficient explanation for why we see only those birds that survive. It would mean that certain stimuli would lead to downgrading of certain processes simply by eliminating them, the ones that survive may not be perfect, but they don't lead to death and hence persist. Does that mean there is one gene doing this? I don't think so, there may be multiple pathways and the ones that don't die, multiply and persist.

If you put a Pima Indian in New York he becomes fat, if you put him in his native environment, he is healthy. What is the reason for this difference? Are his genes modified in the two places?

 

[Gustav]

kinda sorta
if our genes can be likened to a deck of cards, we appear to be able to shuffle them to a certain extent

link link link a primer

The nature of purely physical phenomena can be debated. Are elementary particles just mass and/or spin and/or charge? What about elemental proto-experiences (PEs) as phenomenal aspects that are properties of these elementary particles (quantum mechanically superimposed)?

a most excellent point
a reductionist's nightmare

/snicker

 

[Roman]

I think the fact that if they migrate in the wrong direction, they die is sufficient explanation for why we see only those birds that survive.

Why?
Why not know more?

If you put a Pima Indian in New York he becomes fat, if you put him in his native environment, he is healthy. What is the reason for this difference? Are his genes modified in the two places?

Yes. Some of the genes form active transcription complexes that would not form if a) that gene wasn't there and b) he wasn't eating pizza & beer.

 

[spidergoat]

Exactly. Which is why the selfish gene theory does not work for me. There is no one gene that can achieve complex behaviour. It requires not only multiple genes but also environmental cues that stimulate or suppress expression of those genes to eventually present a phenotype.

Of course, there is most probably no one gene that codes for complex behavior, they work together with other sequences. These sequences still result in a creature with characteristic behavior. Who knows exactly why, that doesn't matter. The environment of other genes is at least as important as the external environment.

 

[S.A.M.]

Of course, there is most probably no one gene that codes for complex behavior, they work together with other sequences. These sequences still result in a creature with characteristic behavior. Who knows exactly why, that doesn't matter. The environment of other genes is at least as important as the external environment.

Yup, thats what I mean. Additionally, in my work, I've realised that food components have a strong influence on the differentiation of cells which mean they turn off and turn on gene functions. Which means that even in a limited group of people what you [don't] eat, will play an important role in what you are. In which case, your behaviour will be a determinant [in the case of pregnant women, for example] of what you reproduce.

Why?
Why not know more?

No reason not to know more, which is why chip arrays are so common these days. The assumption being that if the gene is present, it is functional

Yes. Some of the genes form active transcription complexes that would not form if a) that gene wasn't there and b) he wasn't eating pizza & beer.

You're assuming there is only one gene that has to be present or absent. I'm not.