David Gould

Saw a program last night about Ted Steele and his work at trying to prove that inofrmation can cross the Weismann barrier. I am hoping that some knowledgable individuals here can give me some information on:

1.) Whether it is now accepted that the Weismann barrier can be crossed;

2.) The implications for evolutionary theory; and

3.) What are the problems with it.

RufusAtticus

Umm, what's the "Weismann barrier?" Is it another Creationist/Idist "argument" against evolution?

The Lone Ranger

The experiments so far have been inconclusive. Under some circumstances it may be possible for acquired characters to be passed on in germ cells, but this seems to be a rare and extremely limited phenomenon, if it occurs at all.

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2.) The implications for evolutionary theory; and

Not much really, in my opinion. Steele is talking about possible genetic changes in germ cells occurring due to the parent's exposure to pathogens, as I recall. In principle, this is no different from a genetic mutation -- in other words, just another source of variation for natural selection to work with.

If Steele's right, this would be interesting to be sure, as it would suggest that populations can quickly evolve resistance to infectious agents, through a previously unsuspected mechanism. I don't see that it as throwing Darwinism out the window and going back to Lamarckianism, however.

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3.) What are the problems with it.

See above.

Cheers,

Michael

The Lone Ranger

Weismann was the guy who cut the tails off several generations of mice, showing that acquired characters are apparently not passed on to offspring.

The so-called "Weismann barrier" is the notion that acquired characters cannot be passed on to offspring.

Cheers,

Michael

David Gould

No, its not a creationist thing.

While I am not sure I understand it perfectly, the Weismann barrier is the thing that prevents changes in an indivdiual's normal cells from being passed into an individual's germ cells.

David Gould

Thanks, Lone Ranger. That is what I thought. The show seemed to be painting Ted Steele as some kind of maverick genius opposed to the whole scientific establishment. It made me a bit sceptical of the whole thing.

The Lone Ranger

If this site presents an accurate portrait of Steele's attitude, I'm even more skeptical.

It's not especially helpful to portray your critics as "villains" when you haven't presented any convincing evidence that your claims are even correct, much less paradigm-shattering.

Cheers,

Michael

RufusAtticus

The only acquired characteristics that I've read about jumping from somatic to germ cells are nucleotide-based viruses or transponsons. Also it should be noted that in plants germ cells are derived from somatic tissues.

Nic Tamzek

*What* is it about acquired characters that is so appealing to that particular noncreationist but antiDarwinian fringe? I mean, at least creationists have some fundamental religious reasons, and even the most secular ID fan at least has the "appearance of design" in biology to motivate them.

But acquired characters?

lpetrich

To be precise, animal germ cells, like plant ones, are also produced from somatic cells, but in most species are produced very early in development and set aside.

Also, I think that Steele's mechanism utilizes a certain feature of adaptive immune systems. In such systems, certain white blood cells practice recombinant DNA on their antibody genes, and when they discover an antibody that attaches to some antigen, they stop the recombinant DNA and proliferate with that sequence.

Steele's mechanism is that a white blood cell can contribute an antibody-gene sequence to a germ cell, which will then pass it on. That's a form of Lamarckian inheritance that is entirely consistent with the Central Dogma of genetics; most other sorts of Lamarckism would require extra mechanisms that there is no evidence of.

Imagine what sort of molecular-biological mechanism would be necessary to implement maternal impressions, like the genetic engineering of Genesis 30 in the Bible.

The next question is whether Steele's mechanism actually exists.