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Huh? Recombination refers to the exchange of equivalent parts of nonsister chromatids during meiosis. There are no "more alleles" created during the process.mark kennedy said:When you get more recombinations then you will get more alleles, at least there's a better chance.
mark kennedy said:That's not a tail and the OP was at the other end of human anatomy but I'll bite. What gene causes the human tail (rudimentary organ argument?) to emerge?
Sure, they found 15 indels in coding regions, 14 of which preserved the open reading frame. What is your point in any of this? Insertions and deletions happen in genes. Most of them are deleterious and are eliminated by selection, a fraction are neutral (because adding an amino acid or two to a protein often has no effect on its function -- if they're added in the right place), and a few may be beneficial. None of this adds up to any kind of argument against common descent.mark kennedy said:Of course most of the indels will appear in the nonfuctional parts of the genome, theres less selective pressure there. In the Chimpanzee Chromosome 22 paper they identified gross structural changes in the protein coding genes, 15 in fact, which got me thinking about this. I'm still not sure what kind of indels there are in other chromosomes but I was pointing out that keeping the reading frame open was crucial when there was any change in the amino acid seqeunce.
ChrisPelletier said:It has?
sfs said:Sure, they found 15 indels in coding regions, 14 of which preserved the open reading frame. What is your point in any of this? Insertions and deletions happen in genes. Most of them are deleterious and are eliminated by selection, a fraction are neutral (because adding an amino acid or two to a protein often has no effect on its function -- if they're added in the right place), and a few may be beneficial. None of this adds up to any kind of argument against common descent.
And when are you going to address all of the massive evidence in favor of common descent? You say that we're failing to take seriously the possibility of independent lineages. So what happens if we do take it seriously? Independent descent does not predict that genes should appear in the same order in the two species, it does not predict that chromosomes in the two species should line up, it does not predict that there should be an extra centromere and telomere in human chromosome 2, it does not predict that humans and chimpanzees should share pseudogenes, it does not predict that they should share the particular defects that cause the loss of function in those pseudogenes, it does not predict that human/chimp divergence should be higher in regions of high mutation rate, it does not predict that human/chimp divergence should be higher for transitions than for transversions, and it does not predict that human/chimp divergence should correspond to 6 million years of drift given known mutation rates. All of these things are predicted by common descent, and they're all true. As far as genetics is concerned, independent descent is an utterly worthless hypothesis.
mark kennedy said:One more thing, where are the subspecies that Darwin predicted where an inevitable by product of evolution? Human beings don't have a subspecies, as a matter of fact we don't speciate the way animals do and we have faced every geological challenge this world has to offer, did the single common ancestor model predict that?
Are you ever going to make a point here? You just keep repeating the same things over and over, as if they were an argument against common descent. If you've got an argument in here, I sure can't see it.mark kennedy said:Those are nonsynonomous, coding base substitutions that change the amino acid seqeuence, fixed in the entire genome. What is more they are gross structural changes. Say what you what you like about the synomomous substitutions but the amino acid sequence in protein coding genes? Obiviously, there are going to be a lot of mutations going on and being fixed in the entire genome, what was the ratio of deleterious effects to benefical ones and don't forget the neutral ones.
Yes, it predicts all of that. Some of it requires additional information, e.g. the way that chromosomes line up is required to predict the extra telomere and centromere, but yes, it's all predicted, and all quite straightforward.Does the common ancestor model really predict all of that, or does it interprute everything the same.
I never did think human and chimp DNA was 99% identical. I thought it was 99% identical in the (large) fraction of the genome that was shared by the two species. I didn't know how many or how large the indel differences were, because no one did.Tell me, do you still think that the DNA of humans and chimps are 99% identical are did you have to revise that to, what is it now, 95%?
I've never thought about it. Let's see . . . The average gene is about 1000 base pairs long in its coding sequence. Without selection, we would expect to find an average of 13 differences per gene between human and chimp (based on the genome average of 1.3%). About 2/3rds of coding changes are nonsynymous, so we'd expect about 8 nonsynonymous differences per gene, still ignoring selection. The estimated effect of purifying selection, based on an earlier study in humans, was that 38% of nonsynonymous mutations would survive purifying selection, leaving 3 nonsynonymous changes per gene between humans and chimps. If we assume that selection is uniform across genes (which is isn't) and that all genes are the same size (which they aren't), then the number of nonsynonymous differences will have a Poisson distribution. With a mean of three, that means that 95% of genes should have at least one such difference. That should be something of an overestimate, since small genes and highly conserved genes would have a greater chance of having zero than the average gene -- so finding out that the measured value is 83% doesn't surprise me at all.Did it predict that 83% of the protein coding genes were different
No, the indel rate wasn't known well enough to make a prediction.or that there would be 14 gross structural changes?
You mean there's an indel every 407, right? The rate of differences is higher than that. And no, as I said, we couldn't predict the indel rate because it wasn't well enough known in humans yet.Did it predict that 1 in every 407 nucleotides would be different when lined up side by side?
Predict that what would require hundreds or thousands of mutations? No one knew then, and no one knows now, how many important functional differences there are between humans and chimps.Did it predict that it would require hundreds, if not thousands of mutations in hundreds if not thousands of genes?
Common descent doesn't make any predictions about what is and what isn't selected -- it just predicts the kind of similarities we expect to see. But yes, everyone already thought that the our increase in brain size was the result of positive selection.Did it predict that relaxed functional constraint could not account for the exponential growth and development of the brain in 2 million years, not 6 million years?
Mutation and natural selection have been observed for some time now. You already know that. That they are unable to explain the increase in human brain size is a "fact" that you made up, and for which you have not the slightest bit of evidence.Did it ever account for the level of divergance that has become evident and obvious and offer a demonstrated or directly observed molecular mechanism that accounts for this unprecedented expansion of the human brain from that of an ape?
No. I've tried to get any creationist, anywhere, to explain the observed genetic data based on a creationist approach. They can't. If creationists can't do it, it can't be our stupid, blind prejudice, can it?Or did all the evidence, dispite its enormous burden of proof simply interprute the data in such a way as to make it fit into the single common ancestor model?
There is nothing at all that you could not dismiss as a presumption. Doing so with any intellectual honesty, however, is a tougher proposition. I gave you a list of predictions of common descent. If you want your hypothesis on independent descent to be taken seriously, you had better start, right now, explaining each of them based on your hypothesis. Because at this point my conclusion still stands: your hypothesis is scientifically bankrupt.Where are all of these predictions that cannot be dismissed as presumptions?
Where did Darwin predict that all species should have subspecies? Common descent certainly doesn't predict thatOne more thing, where are the subspecies that Darwin predicted where an inevitable by product of evolution? Human beings don't have a subspecies, as a matter of fact we don't speciate the way animals do and we have faced every geological challenge this world has to offer, did the single common ancestor model predict that?
sfs said:Are you ever going to make a point here? You just keep repeating the same things over and over, as if they were an argument against common descent. If you've got an argument in here, I sure can't see it.
Yes, it predicts all of that. Some of it requires additional information, e.g. the way that chromosomes line up is required to predict the extra telomere and centromere, but yes, it's all predicted, and all quite straightforward.
I never did think human and chimp DNA was 99% identical. I thought it was 99% identical in the (large) fraction of the genome that was shared by the two species. I didn't know how many or how large the indel differences were, because no one did.
I've never thought about it. Let's see . . . The average gene is about 1000 base pairs long in its coding sequence. Without selection, we would expect to find an average of 13 differences per gene between human and chimp (based on the genome average of 1.3%). About 2/3rds of coding changes are nonsynymous, so we'd expect about 8 nonsynonymous differences per gene, still ignoring selection. The estimated effect of purifying selection, based on an earlier study in humans, was that 38% of nonsynonymous mutations would survive purifying selection, leaving 3 nonsynonymous changes per gene between humans and chimps. If we assume that selection is uniform across genes (which is isn't) and that all genes are the same size (which they aren't), then the number of nonsynonymous differences will have a Poisson distribution. With a mean of three, that means that 95% of genes should have at least one such difference. That should be something of an overestimate, since small genes and highly conserved genes would have a greater chance of having zero than the average gene -- so finding out that the measured value is 83% doesn't surprise me at all.
In other words, yes, common descent, along with what we already knew before the chimp genome was sequenced, does indeed predict about the observed number of nonsynonymous differences. (The neat thing is that I had no idea what the answer was going to be when I started typing that paragraph -- I calculated as I typed.)
No, the indel rate wasn't known well enough to make a prediction.
You mean there's an indel every 407, right? The rate of differences is higher than that. And no, as I said, we couldn't predict the indel rate because it wasn't well enough known in humans yet.
Predict that what would require hundreds or thousands of mutations? No one knew then, and no one knows now, how many important functional differences there are between humans and chimps.
Common descent doesn't make any predictions about what is and what isn't selected -- it just predicts the kind of similarities we expect to see. But yes, everyone already thought that the our increase in brain size was the result of positive selection.
Mutation and natural selection have been observed for some time now. You already know that. That they are unable to explain the increase in human brain size is a "fact" that you made up, and for which you have not the slightest bit of evidence.
No. I've tried to get any creationist, anywhere, to explain the observed genetic data based on a creationist approach. They can't. If creationists can't do it, it can't be our stupid, blind prejudice, can it?
There is nothing at all that you could not dismiss as a presumption. Doing so with any intellectual honesty, however, is a tougher proposition. I gave you a list of predictions of common descent. If you want your hypothesis on independent descent to be taken seriously, you had better start, right now, explaining each of them based on your hypothesis. Because at this point my conclusion still stands: your hypothesis is scientifically bankrupt.
Where did Darwin predict that all species should have subspecies? Common descent certainly doesn't predict that
"It might also naturally be enquired whether man, like so many other animals, has given rise to varieties and sub-races, differing but slightly from each other, or to races differing so much that they must be classed as doubtful species?"
"Do the races or species of men, whichever term may be applied, encroach on and replace one another, so that some finally become extinct? "
"With respect to the causes of variability, we are in all cases very ignorant; but we can see that in man as in the lower animals, they stand in some relation to the conditions to which each species has been exposed, during several generations...We see the influence of diversified conditions in the more civilised nations; for the members belonging to different grades of rank, and following different occupations, present a greater range of character than do the members of barbarous nations."
"Extinction follows chiefly from the competition of tribe with tribe, and race with race. Various checks are always in action, serving to keep down the numbers of each savage tribe,- such as periodical famines, nomadic habits and the consequent deaths of infants, prolonged suckling, wars, accidents, sickness, licentiousness, the stealing of women, infanticide, and especially lessened fertility. If any one of these checks increases in power, even slightly, the tribe thus affected tends to decrease; and when of two adjoining tribes one becomes less numerous and less powerful than the other, the contest is soon settled by war, slaughter, cannibalism, slavery, and absorption. Even when a weaker tribe is not thus abruptly swept away, if it once begins to decrease, it generally goes on decreasing until it becomes extinct."
"It is an interesting circumstance that the chief check to wild animals becoming domesticated, which implies the power of their breeding freely when first captured, and one chief check to wild men, when brought into contact with civilisation, surviving to form a civilised race, is the same, namely, sterility from changed conditions of life."
Again, as respects the question of absolute size, it is established that the difference between the largest and the smallest healthy human brain is greater than the difference between the smallest healthy human brain and the largest chimpanzee's or orang's brain.
But since he attained to the rank of manhood, he has diverged into distinct races, or as they may be more fitly called, sub-species. Some of these, such as the Negro and European, are so distinct that, if specimens had been brought to a naturalist without any further information, they would undoubtedly have been considered by him as good and true species.
The idea of a universal and beneficent Creator does not seem to arise in the mind of man, until he has been elevated by long-continued culture.
Jan87676 said:Why do we have to worry about origins anyway? Lets just have a picnic.
Races are not subspecies.mark kennedy said:Now on a beautifull Saturday afternoon I am inclined to agree. By the way, this is about evolution and the notion that there are sub-species of humans. There are not, in fact there is probably more differences within a race then between them.
Tomk80 said:Races are not subspecies.
What Darwin thought isn't exactly relevant, since Darwin lived 150 years before. He laid a framework, but was wrong on many things too.mark kennedy said:Darwin thought they were and dispite facing every environment on the planet Human beings do not speciate, ever.
mark kennedy said:Darwin thought they were and dispite facing every environment on the planet Human beings do not speciate, ever.
Dr.GH said:You are screwing around with the differences in how words were used 150 years ago and today. For a creationist this is absurd because if you subject to Bible to the same sloppy analysis, you should be out supervising public stonings. Have a little self respect.
And, if people didn't move about so much and have so much sex, and such a long generation time they would speciate. I doubt that we will ever speciate due to simple Darwinian processes- not when we are about to start creating designer humans.
Here is an idea; HERVs are leftover alien intelligences. Whoowoow
The single common ancestry model is not Darwin's in particular. Especially in his origin of species, he still argued that there might be more than one single common ancestor, although he raised the possibility of there being a single one.mark kennedy said:Tom,
I'm not ignoring what you said but I don't feel like argueing the relevance of Darwin again. Apparently, Darwin was wrong about everything except the single common ancestor model.
People do not speciate and Darwin insisted that were a naturalist to examine a European and a Negro he would conclude that they were two distinct species, period.
Through the means just specified, aided perhaps by others as yet undiscovered, man has been raised to his present state.
But since he attained to the rank of manhood, he has diverged into distinct races, or as they may be more fitly called, sub-species. Some of these, such as the Negro and European, are so distinct that, if specimens had been brought to a naturalist without any further information, they would undoubtedly have been considered by him as good and true species. Nevertheless all the races agree in so many unimportant details of structure and in so many mental peculiarities that these can be accounted for only by inheritance from a common progenitor; and a progenitor thus characterised would probably deserve to rank as man.
It must not be supposed that the divergence of each race from the other races, and of all from a common stock, can be traced back to any one pair of progenitors. On the contrary, at every stage in the process of modification, all the individuals which were in any way better fitted for their conditions of life, though in different degrees, would have survived in greater numbers than the less well-fitted. The process would have been like that followed by man, when he does not intentionally select particular individuals, but breeds from all the superior individuals, and neglects the inferior. He thus slowly but surely modifies his stock, and unconsciously forms a new strain. So with respect to modifications acquired independently of selection, and due to variations arising from the nature of the organism and the action of the surrounding conditions, or from changed habits of life, no single pair will have been modified much more than the other pairs inhabiting the same country, for all will have been continually blended through free intercrossing.
Tomk80 said:The single common ancestry model is not Darwin's in particular. Especially in his origin of species, he still argued that there might be more than one single common ancestor, although he raised the possibility of there being a single one.
What Darwin was correct about was the framework of evolution through selection of variations that are beneficial for the species. He was wrong about how this variation came about.
I just would like to know why you keep bringing him up, when his opinions on a great many things are not relevant to the current debate, except as one who gave the original framework. Why would you argue about many contexts that he used, when they are not in use anymore nowadays? I don't understand it. Why bring up irrelevant things all the time?
Dr.GH said:
This is exactly what I mean, Mark. You are indulging in the lowest form of creatoism. I have already quoted for you:
[/i]
So, lets look at the next paragraph,
You still don't get it do you?
So try this, Darwin was not ways correct. For example he had totally missed the significance of Mendel's pea experiments. Darwin had no idea at all of the significance of lateral genetic transfer in bacterial evolution or even that it existed. He did not know that bacteria existed. He could not have imagined the existance of enities such as viruses or prions. Not one single person on the planet Earth had any better knowledge either.
If we totally tossed out every thing that Darwin ever wrote, we would still rediscover evolutionary biology providing religious fanatics don't kill every scientist.
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