Doubting Didymus

Is too. One day we'll actually have this debate properly.

Ahh. You're quite right. Skimming the literature I find that this term is currently in common usage in developmental biology and related feilds of evolutionary science in a way that I was not aware of. I have been using the term in a way that is possibly archaic: as a simple synonym for blueprint. I have used it to refer to the idea that genetic information is a blueprint of the complete organism, a hypothesis that very few people believe (that know what they are talking about at least).

I have not seen it used in the more literal sense "body plan", where it does, indeed, refer to the role of (to put it in laymens terms) this kind of 'cascade' of information in the form of the positions of various cells that strongly influence the fundamental 'layout' of the organism (bauplan or body plan, of course).

Come to think of it, It was very silly of me to engender this confusion, as I myself have started a thread or two on 'fundamental body plans' in which I used the term in more or less that exact sense.

Please ignore any use of the word bauplan in my previous post, and replace it in your mind with 'blueprint', meaning the idea that genes encode a precise and exact plan of how the finished organism will turn out.

Abacus

Could you elaborate on this? I did a web search for "bauplan analogy", but it didn't come up with too much.

Doubting Didymus

No, nor I. For an Idea of what PZ is talking about, try "positional development", "bauplan" and "metazoans" in various combinations. That seems to be the proper sense of the word.

Myself, I was referring to the part in The blind watchmaker (I'm fairly confident it was that one) where dawkins dismissed the idea that genes are a blueprint, that they have a decent direct relationship with the phenotype, and thus can give you a decent idea of what the organismthat they encode will be, if only you could crack the code. He replaces this with an analogy that is his own original, as far as I know, which is the 'recipe' analogy. To him, genes work as a recipe, specifying certain ingredients, regulating them, and giving other instructions on the general proceedings. Just like in cooking, the finished product can be different from the recipes ideal in a variety of ways.

This is often cited in nature V nurture debates that were all the rage some years ago, and the idea that genes are not a blueprint of physical destiny is largely accepted and often cited. The connection to evolution / creation is not obvious, which is why I suspect your freind is thinking of dawkins. I suspect that your creationist freind has gotten it into his head that dolly the clone refutes dawkins's ideas about genes not being a blueprint of a destined final product, and anything that hurts dawkins hurts evoltuion in a lot of peoples minds.

Abacus

Okay, thank you for your responses everyone.

Let's see if I understand you correctly. Aside from red blood cells, all other cells contain a complete set of genes. However, these genes are a recipe, not a blueprint. Although Dolly was a clone, she was not identical to the sheep she was cloned from. Evolutionists have known that this would be the case since long before Dolly was born. Therefore, my creationist's assertion that Dolly's birth invalidates evolution is bunk.

Doubting Didymus

Sounds about right. I would also point out that even if dolly DID prove that all cells contain an accurate blueprint, that fact would not present any problems for evolution at all. In fact, It would probably make it a lot simpler to get a full picture of.

Abacus

Thanks. I'll do that.

Of course, I may be wasting my time with this guy. He also asserted that since evolution is only a theory, it is not a science. He made this assertion after I tried to explain the difference between the word "theory" as scientists would use it, and how the rest of us knuckledraggers usually use it. Gee whiz, I guess old Albert Einstein wasn't really a scientist then. Relativity is only a theory, you know.

charlie d

I'd add lymphocytes to the list of somatic cells with non-germline genomes. During their differentiation, each lymphocyte has to rearrange some of the genes involved in immune responses in order to generate highly diverse functional receptors able to recognize invading pathogens and foreign substances ("antigens"). Because such DNA rearrangements include the permanent deletion of large pieces of genetic material, lymphocytes can't really "go back" to the original genomic status.

Interestingly, lymphocyte nuclei have been used to clone mice, which as predicted displayed the same exact kind of antigen receptor in all their cells, instead of over 10^10 different ones of normal animals. Pretty cool.

Abacus

God Bless her soul.

Hmm. Would a cloned sheep even have a soul? Such an important question.

Oolon Colluphid

DD, just to note that you’re right, it is in Blind Watchmaker that Dawkins demolishes the ‘blueprint’ analogy, suggesting ‘recipe’ as closer to the mark. However, I’m pretty sure he didn’t refer to the term bauplan till Climbing Mount Improbable, and iirc he used it nearer to how pz at al use it.

I’d not heard of it till then at least, and I took it at the time (whenever CMI came out) to mean something like ‘bodyplan’, the more fundamental shapes of stuff like number of segments, which end is the head, and so on: the things that the early-in-the-cascade genes are involved in.

Will have to re-read CMI, but I doubt that in reality there’s much difference between pz’s and Dawkins’s positions.

Cheers, DT

Doubting Didymus

A bit of reading shows that this is the case. For some reason I thought Dawkins used bauplan as a synonym for blueprint, which he did not. My bad.

Yup. I believe he uses the term a lot whenever he is ranting about the cambrian explosion, which he does quite often. He seems to use the term quite literally, simply meaning the fundamental layout of the organism.

I doubt dawkins would agree that positional information influencing the bodyplan can be selected for or can evolve in the darwinian sense, which I think pz would want to say. But you are right that they use the term to describe similar things. It's ME thats all turned around on the issue.