The End of Evolution By Means of Natural Selection

Why can't evolution happen if mutations introduce new genetic variation over time?

Food for thought. The human genome differs from the chimp genome by about 2% within homologous DNA, and by about 5% when insertions and deletions are considered. According to your logic, humans are heavily diseased chimps.Or could it be that changes in DNA lead to new phenotypes that do not cause disease, and can even be beneficial in certain circumstances. Perhaps you should think on this for a bit.Edited by Taq, : No reason given.

There is nothing assumed about the differences between humans and chimps. The DNA differences are a fact. Those differences add up to 2% for homologous sequences and 5% if you consider insertions and deletions. If memory serves there are about 60 million differences at the nucleotide level. So are you really telling us that humans are suffering from 60 million genetic diseases? Are you really expecting us to believe that none of those differences are beneficial to humans? It doesn't matter how those differences go there for your argument, by random mutation or by design. The fact still stands that changes in DNA are beneficial and do not necessarily cause disease.Or perhaps you can tell us which differences between humans and chimps could not have been produced by random mutation. How does one determine this?

According to this logic we should find the exact same gene in every species, down to the base. Is this correct? Afterall, any deviation will result in disease, right?

According to you any deviation from a specific DNA sequence will cause disease or non-beneficial oddities. Therefore, if two species share the same gene then the DNA sequence of that gene should be identical.If the mutation hypothesis is correct then there should be deviations of genes between species, and this deviation should correlate with evolutionary distance. Furthermore, some of these deviations should be responsible for the adaptations seen in each species, and should therefore be beneficial.Which do you think is true?

All things being equal, the ratio of black to other colors within the population will stay the same in every generation. You will always have black heterozygous parents having not-black offspring.

What about the 65 million base substitutions seen between humans and chimps? About 2% of the bases are different between the human and chimp genomes, and a 5% difference if you include additional or absent DNA sequences (i.e. indels). According to your logic, humans are heavily diseased chimps, or chimps are heavily diseased humans, take your pick. In fact, every species is heavily diseased because each species differs from the next in the DNA. If you are going to hold on to the argument that mutations only lead to disease then we should only see a single species, or the genome of each species is made up of different alleles that share 100% homology with another species.Or you can face the music. DNA can be different. Those differences are responsible for each species adaptations that they require to survive in their niche. This leaves you with a rather large challenge, showing which differences can not be produced by random mutation. So which of the 65 million DNA differences between chimps and humans produce disease? Using your 1% figure here I could only assume that each human is suffering from 650,000 genetic diseases. So you are saying that none of the differences between humans and chimps is beneficial to humans? The actual evidence is the genome of every species which can differ greatly in their DNA sequence by thrive nonetheless.

You have it the wrong way around. The differences between varieties is due to differences in DNA sequence which occur through mutations. Using three closely related species (e.g. humans, chimps, and gorillas) you can determine the common ancestral sequences and the mutations that have occurred in each lineage. What does that mean? To put it in neo-Darwinian terms, mutations modify the structures. Our limbs are modified fins, as one example. Two of our middle ear bones are modified reptilian jaw bones, as another example. Pick any two species. The differences between those two species is due to a difference in DNA sequence. How can mutations not be responsible for this? Not at all. Speciation is the fixation of DIFFERENT MUTATIONS in each lineage (which is even stated in the Wiki page). Divergence is the key here. So humans are a variation of chimp? Of the DNA differences between humans and chimps which required something other than the observed mechanisms of mutations? Care to enlighten us? Why not? Because you say so? Is this or is this not due to a difference in DNA sequence? If it is, then please explain why a mechanism that changes DNA sequence is incapable of producing this change?

Unless, of course, we are talking about selection of the additions. "Blur the character of that population"? What the heck does that mean?You seem to start with the assumption that species can not change through mutation, and then discount mutations because they would change the species. Am I right here? You get 100-200 point mutations per person throughout the genome and the rarer insertion or deletion of DNA. From memory, about 2 to 3 result in an amino acid change in a known open reading frame. Also, there will be mutations in regulatory DNA as well which can produce change as well. Unless, of course, it is selected for in a smaller, isolated sub-population through a process called allopatric speciation. So why are humans and chimps different? It is due to the differences in their DNA, is it not? Those differences are also adaptive, are they not? Obviously, changing DNA can result in beneficial and adaptive function. Every living species is proof of that. If it were not possible for mutated DNA to be beneficial then there would be only one species alive today. That is completely false. A mutation in a regulatory gene can change the expression and function of several other genes. There is no arm gene, no eye gene, no leg gene. Features are the result of numerous genes interacting with one another. A mutation can change how multiple other genes interact with one another. What genes do humans have that chimps do not, and vice versa? From my reading we share more than 99% of our genes with chimps. The sense I get from the scientific literature is that the differences between humans and chimps is not due to different genes but different sequences within homologous DNA (be it genes or regulatory DNA).You want to claim that changing DNA can not result in a new species, and yet we have billions of species because the DNA is different. It is changed. How can you ignore this fact?Edited by Taq, : No reason given.

Speaking of blood types . . .A new hemoglobin allele is being selected for in areas with endemic malaria. This mutation allele is hemoglobin C. Carriers of this allele suffer a less severe case of malaria. They are fitter. The C allele differs from the widely known S (sickle cell) allele in that the C allele does not cause anemia in homozygous carriers. At the same time, the C allele does not confer the same resistance to malaria that the S allele affords, but the reduced fitness cost for homozygous carriers along with the attenuation of the disease makes the C allele the fittest. The C allele is actually expected to replace the S allele in some areas in Africa over the next 50 generations (assuming a cure is not found in the mean time).

quote:

---

Estimation of relative fitnesses from relative risk data and the predicted future of haemoglobin alleles S and C.

​

Hedrick P.

​

School of Life Sciences, Arizona State University, Tempe, AR

​

Abstract
Epidemiological studies of genetic differences in disease susceptibility often estimate the relative risks (RR) of different genotypes. Here I provide an approach to calculate the relative fitnesses of different genotypes based on RR data so that population genetic approaches may be utilized with these data. Using recent RR data on human haemoglobin beta genotypes from Burkina Faso, this approach is used to predict changes in the frequency of the haemoglobin sickle-cell S and C alleles. Overall, it generally appears that allele C will quickly replace the S allele in malarial environments. Explicit population genetic predictions suggest that this replacement may occur within the next 50 generations in Burkina Faso.

---

This goes back to my rain analogy a few pages ago. The only way you get rain is by reducing the amount of moisture in the air. According to your logic, we can only conclude that the Earth should run out of rain within a month or so. Add all the water you want from water evaporation, it doesn't matter. Rain still requires a reduction in atmospheric water vapor so it will run out. This is your argument.How can there be an end to the line when mutations, the source of new variation, never stops?

Darwin did a fine job of illustrating it in "Origin of Species", link. He showed a pattern of descent with modification leading to divergence between lineages. This is how it works at the genetic level. Populations that no longer interbreed accumulate different mutations leading to divergence over time. It is the same way that we have Romance Languages that diverged over time while sharing a common root language.

What about the millions of new alleles created through mutation? If we go with 1 new allele per individual per generation in a population of 1 million that is 1 million new alleles per generation. Are you really suggesting that selection will remove more than 1 million alleles per generation, not to mention the off-hand mutation that creates new genes from previously non-functional DNA? Not to mention the new promoter sequences inserted by the occasional retrovirus or retrotransposon? And that brings us back to my rain analogy. You would argue that since rain requires a reduction in atmospheric water that the Earth should run out of rain in about a month. Your model explicitly ignores water evaporation creating more atmospheric water vapor for no other reason than "new water" would "blur the character of the atmosphere".Why doesn't it matter that there are new alleles being created faster than old alleles can be removed from a growing population? This is never expected of every mutation. If I have a mutation in a specific allele does everyone in the world with the unmutated allele suddenly disappear? No. The old alleles are passed on along side new alleles. Since our genome is 98% similar to that of chimps does that mean that our genome is 2% destroyed, or that the chimp genome is 2% destroyed? Or could it be that differences in DNA are responsible for the differences between species? Why won't you answer these questions? Why would it stop at a single iteration of "new alleles then selection"? Why wouldn't this process continue ad infinitum? Also, replacing old alleles with new alleles in generation after generation would lead to new species, would it not? That is exactly what we see in living species, is it not?Here is another analogy for you. Let's say that you are given 5 random cards out of the deck. You are told that a flush is the best hand you can get in the current experiment. You are allowed to draw one card at a time and discard one card at a time. Any card gets you closer to a flush is kept. Any drawn card that would worsen your hand is discarded. For a card that neither improves nor worsens your hand you flip a coin. Heads you switch it with another card, and tails you discard it. What would happen over time? Old cards would be replaced with new cards, would they not? The hand would change over time through changing the cards.Now lets say that you end up with a royal flush at some point, the best possible flush. There are very few, if any, changes that will improve your hand. Let's reproduce this hand. Get another deck and give it to someone else. Find the exact same cards that make up your hand. Shuffle the two decks. Now the environment changes. Now the best hand is four of a kind. Now there are two populations that can not exchange cards. Follow the same rules as above. What do you find? After each draw (i.e. mutation) the hands become less and less alike. Not only that, but since you are drawing from a different mutation pool you will get different mutations (i.e. different cards) at different times. You will also find that the first card you pair quickly becomes fixed in each population. Let's say you pair your jack first, but the other person pairs their king. From that point onward chances are only a king will better their hand, and only a king will better theirs. This is how populations diverge over time even if selection is nearly the same. Now just imagine if the two hands of cards were put under different selection, such as a full house vs. a low straight. They would look even less and less alike over time, would they not?Your model can not even handle this very simple example, and it certainly can not handle how genetics is observed to work. The observed human mutation rate is capable of producing the genetic differences seen between humans and chimps in a time span of 5-7 million years, the exact same time since common ancestry supported by the fossil record. The observed mutation rate is capable of producing the DNA differences we see between species, and it is those DNA differences that are responsible for the phenotypic differences between species. The DNA in every one of your cells is evidence of this. How can it be shrinking when millions of new alleles are created in every generation through mutation? How can you tell the difference between an original allele and an allele that has arisen through mutation? What tests do you use to determine this?

You are arguing that every species on Earth, including populations with millions and even billions of individuals, are running out of genetic material that they need to evolve. Obviously, you are talking about any sized population. So your model only applies to shrinking populations or stable populations with only a few hundred to a few thousand individuals? Are you saying that your model doesn't work for populations that are increasing in number or for populations that number in the the tens of thousands to billions? Are you saying that your model can't even work for a couple milliliters of bacterial broth that is doubling in number every 20 minutes with billions of bacteria? It would seem that your model isn't applicable to 99.9% of biology. I am not "eager" to get rid of them. What I am is eager to explain reality, and in reality old alleles are replaced by new ones. Not an assumption. A fact. It is a fact that the differences in the human and chimp genome are beneficial to humans and chimps, respectively. Obviously, DNA can be changed so that it is beneficial to a species. I am not talking about similarities. I am talking about differences. You claim that if DNA is changed it can only be non-beneficial or deleterious. If this is so then you must explain how genomes of different species can be different without hurting each species. I AM TALKING ABOUT MUTATION + SELECTION. I will, as soon as you show how reduced genetic diversity is responsible for the differences between humans and chimps.

So now you define macroevolution as "destroying a species"? All evolution requires is imperfect reproduction and competition for limited resources. Evolution does not require a species to stay the same. In fact, it argues for the exact opposite, that species do change over time due to random mutations that are filtered through selection. How can new varieties or breeds be selected for without them first existing? You seem to be arguing that evolution can't occur, and that evolution occuring doesn't count as evidence. Only if you ignore the increase in genetic diversity created by mutations. Mutation = new variety For humans with a mutation rate of 150 mutations per individual per generation, a generation time of 25 years, and a stable population of 6 billion that would be 150*4*6 billion or 3.6 trillion or 3.6E12 mutations. If just 1% of those mutations occur in coding regions that is still 36 billion mutations total in the human population.