big breakthrough in Evolutionary Biology

Dear Schrafinator,
I read this article and it is more of the same: loss of traits. How can you be so happy about the loss of characteristics, while you need the gain of traits in Darwinian evolution? Evolutionists' logic really puzzles me.
Best Wishes
Peter

dear Shane,You write:
" think you overlook the implications of this paper. Genetically there has not been a loss- only a very slight change. The process is believed to have originally occurred from multilegged ancestor to six legged progeny, but could occur in the other direction via an equally simple genetic modification. The gain or loss of structures is arbitrary because the genetic change is simple and therefore quite possible in either direction."If I overlooked the article, and if this is all so simple, please explain to me where did the genes that specify the legs of the multilegged organism come from?best wishes
Peter

dear Schrafinator,I have had a careful look at the nature paper (21 Feb 2002) you refered to.
In the link you mentioned in your posting it is claimed that:"...the scientists show how mutations in regulatory genes that guide the embryonic development of crustaceans and fruit flies allowed aquatic crustacean-like arthropods, with limbs on every segment of their bodies, to evolve 400 million years ago into a radically different body plan: the terrestrial six-legged insects."As a matter of fact this is not what the authors show in their Nature article.
All the authors show is that suppression of the abdominal limbs in insects depends on functional changes in a protein called Ultrabithorax (Ubx), which is encode by a Hox gene. Ubx represses the expression of another gene, Distalless (Dll), which is required for limb formation, in the anterior abdomen of the drosophila embryo. In the crustacean Artemia all of the developing limbs have high levels of Ubx. (As expected since they have more limbs).The rest of Schrafinator's reference is interpretation and extrapolation accompanied by a figure of a shrimp-like organism and some insect (to what purpose?).Why is nobody reading these papers for themselves? You will find out that evolutionists are not objected by jumping to conlusions. I strongly object to this type of "science".Best Wishes
peter

dear Percy,You say:
"I had somewhat the same reaction when I first read the article back in February, but you've missed the important point. The puzzle was how morphological changes that require multiple gene changes across chromosome pairs could come about given that they're so incredibly unlikely. The results of the study revealed that a single change to a dominant Hox gene on a single chromosome can have a dramatic impact on body plan by turning on or off multiple genes on other chromosomes."Q) Is the change so "incredibly unlikely" that it is non-random (directed) mutation?And:
"You probably believe the example illustrated in the article where six-legged insects evolve from multi-limbed crustacean-like ancestors is a case of loss of information or de-evolution, but it's actually an example of suppression of expression."Suppression of expression is de-evolution, since the genes are present but not expressed. Did the genes that are not expressed become redundant? I would like to see the entire sequence of the suppressed genes in distinct organism. That would make it easier to interpret the data. Otherwise, unwarranted conclusion jumping is all the authors do.
What I strongly object to is that the innocent reader is mislead by the presented figure. It does not cover their research at all.In addition, a leg is still a leg. Of much more interest would be the appearance of a functional wings in a "shrimp" by a single mutation.And:
"Insects evidently still have the information for multiple limbs, but information was added to their genome, specifically in Hox genes, instructing many of the limbs to not be expressed."This is also an unwarranted conclusion. It can only be concluded from (over)expression studies in insects and that is not what the authors did.And:
"The opposite process whereby an organism acquires limbs not previously present is, I think, well understood, but I have no reference I can provide."That's a pity. I think I know what you mean. It involves segment duplication."Perhaps someone else here knows more about this, but a couple possible avenues are obvious. Gene duplication is one where during reproduction two copies are accidentally made of a single gene."Q) Where did the first gene come from?And:
"Another is a Hox-like approach where one gene controls how many times another set of genes is expressed. It's a simple change from saying "five limb segments" to saying "six limb segments"."That's it, but it is not so simple as you think it is.best wishes
Peter

dear schrafinator,You write:"I never grew any bottom wisdom teeth. They simply do not exist.While you may consider it a "loss", I consider it a wonderful adaptation, because I didn't need to get any dental surgery."Adaptation to dental surgery?
The loss/gain of the wisdom teeth may be the result of a preexisting mechanism that influences gene expression and invokes variation in the human population. For instance, the Alu-sequences in humans may be responsible for differential expression of traits in subpopulations, but may even be responsible for father-son differences."When the land mammals which evolved into whales lost their limbs, it was an adaptation to moving through water."This has never been observed; it is extrapolated (and an unwarranted conclusion) from the fossil record. Besides, according to ToE whales did not loose their limbs but their legs changed into flippers.Horses used to have many toes, but now they only have one.Incorrect. They use only one "fingernail" to walk on. (By the way, read Spetner and what he has to say on horse evolution)The ToE doesn't require constant "additions", so you saying that it does belies your misunderstanding of the Theory.It may be so that --in your opinion-- evolution does not require constant "additions", but could you than please explain to me how a bacterium became a primate, or --simpler-- how a prokaryote evolved into a eukaryote?"All the ToE requires is change."Not entirely true. ToE needs upward change. I do not doubt the existance of variation (=change)."It might be change that leads to more complexity, or it might be change that leads to less complexity. IT doesn't matter."Please explain to me why --in your opinion-- it doesn't matter. Of course, it matters whether we find new genes in an organism or whether genes are inactivated. Your statement demonstrates that you do not know the ins and outs of evolution theory and the problems it is facing."It all depends upon what the environment selects for and what variability exists within the population."If there are no new genes/traits which provide adaptive advantage there is nothing to select.Best wishes,
Peter