It is amazing how random mutations supposably get it right with specific information at specific places within the genome. So far I remain unconvinced that the genome rolls dice. If it is random, then there should be a lot of trial and errors in the genome
Quite correct, which is why a good sign that Evolution by random mutation is correct is the fact that we see a lot of trial and errors. Let's see, considering that I'm not a geneticist by any stretch of the imagination, how many things we have seen that would constitute trial and error in genes I can come up with:
Down's Syndrome genetic deformations (such as two headed snakes, cows and frogs, or frogs with multiple extra limbs, etc) Sickle Cell anemia the sheer number of pregnancies that don't even make it to term because the embryo or fetus that is developing has so many genetic errors that it is incompatible with life
And those are off the top of my head. If I took .002 seconds and did a Google search, I'm sure I could find more. Let's see what you can come up with.
This trial and error is particularly interesting in that it is detrimental to the health of the organism, except that it also provides significant resistance to malaria. It is a trial that resulted in what we would consider to be an error, except that it also becomes selected for in certain circumstances.
Sort of. Being heterozygous for the sickle cell gene grants the malaria resistance, but being homozygous confers the actual anemia. So, I would consider anemia to be an error and being heterozygous to be the advantageous set that keeps the possibility of anemia in the population. But, since I'm not an expert, I could be speaking out my ass.
That is a fairly good counterpoint. However, some of those problems are rather rare and of course the sickle cell is something that protects against a specific serious disease. I'm not saying the sickle cell was designed. I'm saying it is probably the result of blind natural Darwinian evolution.
Yes, the fact that they are rare is because the odds of the right mutation at the right spot (or in actuality, any non-positive mutation occuring anywhere in a coding part of a gene) are relatively small...until we factor in the sheer number of births taking place. So, the instances of beneficial mutations occuring are rare ( we all assert this) but again, when you take the sheer number of births happening, the odds of a beneficial mutation occuring is close to 1.
The number of pregnancies that don't go to term is, of course, an estimate, but the estimates are quite high, on the order of half to perhaps even 90%, so in that case, deleterious mutations occur very often, but the mother either rejects the fetus, or the fetus just doesn't/can't survive, resulting in a miscarriage. So, there is a mechanism for weeding out the vast majority of harmful mutations, while letting neutral and good mutations through with a few harmful ones that are just good enough to make it.
And how do some of these accidental mutations arise in the first place? Could they be the result of toxins or the problem with defenses stemming from insignifigant nutrition?
Those reasons and more. I don't see what this has to do with your point, unless you're agreeing with me that mutations occur all the time for many, many reasons.
In order to acheive a specific effect that is beneficial to the organism
But there is no specific effect being "looked for." You could shuffle and deal cards all day looking for the right set of circumstances that will lead you to a royal flush, but if you stop worrying about a specific outcome and merely look for the hand that will beat the other hands at the table, you find them quite regularly. And in fact, the odds of you getting that exact full house of 8s over 2s is just as unlikely as the royal flush. Yes, the exact mutation to help organism A overcome hurdle B that we see in nature is exceedingly low on the probability table, but one of the organisms in the population finding some way to overcome hurdle B and thus being able to survive better is very high on the probability table, even if each and every specific "answer" is low. That's what we're (especially PaulK) is trying to get across. You're looking at the probability of a specific mutation (or a specific card hand) and people who know about evolution, if they even consider this question at all, know to look at the probability of any old mutation that would help.
Can't random mutations occur anywhere in the genome?
Yes, and they do. The vast majority of which are so harmful that the fetus spontaneously aborts before completing gestation.
I also sometimes get the impression there exists confusion of ID with Creationist thought. The science behind ID doesn't tell us what the intentions of the designer were. If the Japanese won WWII, we probably would have been worshiping the God of the Rising Sun.
That's because ID was hatched by Creationists who wanted to get their brand of religion taught in schools instead of evolution, and is promulgated by creationist institutions and creationist lay people who want to find a "scientific" basis for their religiously derived beliefs. That there are a couple non-creationists out there who also favor ID doesn't stop the fact that the vast majority are creationists who want to hide that fact from school boards and the public.
Thanks. I had heard some estimates that up to 90% of pregnancies ended in spontaneous abortions, and I assumed, if that were true, then many of them would have been from mutations that caused the fetus to be unable to survive.
But yeah, I understand that even if one mutation is detrimental enough to cause spontaneous abortions, there could have been any number of other mutations that may have been beneficial or neutral that got wiped out because of the one really bad one.
I guess I should make sure I'm clearer when I make sweeping generalizations.
I could be entirely off base here, but as I understand the whole "Chinese whispers/telephone" or "DNA as a language" side topics, one poster had said that substituting a wrong letter in a sentence turns the whole sentence to gibberish, whereas substituting one base in a strand of DNA won't make it gibberish, it will just have some (whether small or large) effect on the protein that is made, and will therefore have an impact on that protein's ability to carry out it's "intended" function. As you point out, if the mutation is in the third spot of a codon, it may have no effect at all.
The Cambridge University study was referenced merely to refute the idea that changing one letter in a sentence m akes the sentence gibberish since we can still understand the sentence as it was written. Likewise, no matter what you do to change the order of DNA bases, there will still be some protein created, and that protein will have some effect in the cell, whether good or bad.
You were doing well up until here. There are a number of forms of mutation which could in fact stop a protein being created. The most ovious is a mutation which removes the start codon for the gene.
Yeah, I thought about putting in the explanation of the start and the stop codon. (If the stop codon was placed directly after the start codon, nothing would be produced, correct?) But thanks for clearing up any miscommunication on my part. That's one of the great things about this forum, we actually have people in the fields who know what the hell they're talking about rather than a bunch of lay people with an interest who will mangle the actualities left and right.
Well, when we don't know the answer, that's as definitive an answer as you can get. However, we have chemists and biologists working on this problem and making very substantial headway. I would expect an answer within my lifetime.