Peez

Because you have not demonstrated any inheritance. Please explain how "maternal localization of gene products", "axis formation", and "induction" are inherited. I was simply trying to point out that the examples that you gave appeared to be examples of phenotypic plasticity, not inheritance. This is not rhetoric, it is explaining why I do not think that these are examples of non-nucleotide inheritance that "make substantial contributions to the form and function of organisms." Not at all. I was simply pointing out that the examples given did not appear to me to be inherited. Please do not pretend to understand my motives. I have made no attempt to trivialize anything. I am sorry, perhaps I should have explained what "maternal effects" are. It was not my intention to imply that the structure of follicles or nurse cells in Drosophila (or any other organism) fade away, that is not "maternal effects" (and these structures are likely determined genetically ). Here is how Futuyma defines a maternal effect: When I said that maternal effects tend to fade after a couple of generations, I did not mean that there are less maternal effects between a mother and child this generation than there were a few generations ago. Rather, I meant that the maternal effects of a mother on her child fade before getting to her grandchild, and even more so before her great-grandchild. Of course it is, I never claimed otherwise. I have not claimed otherwise. No, of course not. Do you really think that I have taken that position?

Peez

Peez

Given that evolution may be defined as a change in gene frequency over time, then it should not be surprising that many evolutionary biologists are interested in population genetics. This is circular (saying that evolution is about allele frequencies because it is population geneticists who gave the definition, but evolutionary biologists are population geneticists because evolution in about allele frequencies). By one definition, evolution is only about changes in allele frequencies, by another it is not. Actually, I would argue that it is just as easily a trait of an individual. It doesn't matter, because there are lots of changes to traits of a population that I do not consider evolution. Very often. No doubt. Note that a plasmid is a piece of DNA. You can call it "infection" if you wish to, but the addition of a plasmid is inheritable. I am willing to be flexible about Wolbachia (I don't know much about it), but it sounds as if it will become an argument over what constitutes an individual organism. Nucleic acids do not so much cause evolution, they define it (at least, for "some" of us ), because DNA is copied and passed along more or less unchanged to descendants. That would not necessarily be a reason to define evolution in terms of allele frequencies. I would argue that the reason evolution is defined in this way is that it covers inherited changes in characteristics of individuals from one generation to another in a population. Yes, the phenotypic variability. Potentially, but note that this is not always the case. By "genome" I assume that you mean the DNA in the nucleus/nucleoid? I have not made any such restriction. I have no problem with inheritance involving alleles that are not found in the nucleus/nucleoid. Agreed. I am afraid that I still do not understand. It would help if a specific example of non-nucleotide inheritance was provided. For example, what trait might I inherit from a grandparent that did not get passed through DNA?

Peez

Peez

That is certainly one of the points that you have made, but one with which I have no quarrel. I have never stated or implied that "the environment and epigenetic influences (should be) dismissed as ‘just the environment' or as incidental by-products of gene action", nor have I claimed "that eventually, if you trace it back far enough in development, everything in the organism can be derived from the genome". Whether it is "usual" or not is immaterial. That is a curious use of the word "trivialize".

Peez

Peez

I would disagree, depending (of course) on how one defines the "tools of population genetics"). Certainly not. Just because we cannot go back in time and actually measure allele frequencies does not mean that we cannot think of evolution in those terms. I note that you have ducked the question. I asked for a potential explanation for birds evolving from "reptiles" without changes in allele frequency, and you did not answer. I also asked about how reasonable a question it is, and you failed to address that as well. Can we answer questions about bird evolution without actually measuring allele frequencies in ancestral birds? Of course. Just because you cannot directly measure changes in allele frequency does not mean that allele frequencies are not changing.

Peez

Peez

Um, who said that genes are responsible for everything?

Peez

Peez

Could you provide a reference for that? I know that there is a lot of speculation about abiogenesis, but I was not aware that these details had been agreed on. I had been under the impression that the most popular hypothesis was that relatively simple nucleotides were the first replicators, and that they evolved into cellular life forms later. Naturally, I do not accept this as gospel, but it sounds as reasonable as any other hypothesis that I have heard.

You might also explain how it is relevant. If non-nucleotide inheretance appeared first, how would that change how inheritance works now?

Peez

Peez

I do not wish to quible about semantics, but I agree that genes exert their influence on cell membranes indierctly. Yup, almost certainly important in the formation of the first cells without the help of any nucleic acids. Absolutely. These membranes will not assemble in a non-polar environment (at least, not the same way), for example. Yup, and virtually none of those componants make it to individual cells of the adult offspring, nor are they passed along to the offspring's offspring. On the other hand, it might be that the expression of DNA is influenced by the environment.

Peez

Oolon Colluphid

You do ‘condescending’ nearly as well as vanderzyden. It prompts the response: Mike Harding once said something to John Lennon, and relates that Lennon replied with a two word answer. One word involved sex, the other, travel.

Ditto.

pz, go back to page 1. I said just what you have about other factors in development-evolution. Of course they're important, and if you'd actually read my earlier post you would know that my one above was a simplification. Only one of the factors involved in the making of a body is actually copied down generations though, as far as any book I've come across says.

Your dismissal of my post is "revealing of the default mindset": you're in genetic denial. If evolution is a change in alleles, just what the blue fuck are alleles then? Why bother to even consider them? Let me know when the Human Cytoplasm Project gets underway...

Oolon

pz

You need to go somewhere quiet and cool off.

My apologies if I seem condescending. That is not my intent. I've been trying to explain something, and you consistently miss the point. You still don't get it.

I really am not trying to demean you at all here, I'm just trying to communicate an important story in biology.
As I've said quite a few times already, this is not true. Seriously. The gametes of all organisms are rich in non-genetic information that is generated epigenetically. That means that significantly more than just genes are inherited. Your books are at best pushing an oversimplification, or at worst, just plain wrong.

This is not condescension.
Not at all. I'm well aware of the significance of the role of genes in development and evolution. Heck, I teach genetics.

I'm just telling you that there is more to the phenotype than genetics, and that seems to be getting you strangely pissed off.
And now you're getting incoherent. I did not claim that alleles don't exist, are unimportant, or that they don't change in frequency. I said that there is much more to evolution than is covered by the "change in allele frequencies in a population" definition. Perhaps this irritates you, but it is the case that that definition, while useful and operationally productive, is deficient. Don't take it too personally, please.

RufusAtticus

Peez,

My point is that evolutionary biology is about more than population genetics, which, as far as I can tell, you are advocating that evolutionary biology is only population genetics.

Addition of wolbachia is also inheritable.

And wolbachia reproduce and are passed along more or less unchanged to descendants.

Ahh, but wolbachia-infection is an inharitable change, that isn't covered by the gene-pool defination.

I understand that you are taking a broad view of "allele," but I don't understand why you have a problem with extending this to non-nucleic acid inheritance.

Wolbachia

That's from the other discussion in this thread. It applies to the thought that an organism can be reduced to it's genome or a population to it's gene pool.

~~RvFvS~~