Evolution Requires Reduction in Genetic Diversity

Mutation doesn't stop after a selection event. It is going non-stop in every single generation. Each time a new individual is born in the population you get an increase in the genetic diversity of the population because that individual will be born with a genome sequence that has never existed before in the entire history of that lineage.You might as well be arguing that rivers should run dry in a year's time because rivers only flow downhill, they can't flow uphill to replenish the water flowing downhill. Just as rain replenishes the water needed to flow downhill. so too does mutation produce the new genetic diversity that flows through selection.

Prior to that point, you had an increase in the genetic and phenotypic variation within the species. So at one time you had the A allele. A mutation produces the B allele. The B allele becomes more common to the point that 50% of the population has allele A and 50% has allele B. So you started with just allelel A, and then you had A and B. That is an increase in genetic diversity.

New mutations occur in reproductively isolated and inbreeding populations as well. New mutations will occur in each of these new species which will increase the total genetic diversity of the clade given that these mutations will not be lineage specific due to different selective pressures.

This means that genetic diversity starts to increase after a strong selection event.

How do you get a new phenotype other than through an increase in genetic diversity? How do you get competition between alleles without the production of new alleles which is an increase in genetic diversity?If we start with 100% allele A and later end up with 50% allele A and 50% allele B, would you count this as an increase in genetic diversity?

If it can be shown that the other beak comes about due to a new mutation, would you count this as an increase in genetic diversity?

Once it appears, the genetic diversity has increased, has it not?It would seem to me that you have competing mechanisms: one that increases genetic diversity and one that decreases genetic diversity.

Of course, since that is the definition of gene pool. What you are ignoring is that each generation adds new mutations to the gene pool, mutations that didn't exist in the previous generations. It is equally silly to think that no mutation can lead to a change in phenotype. The genetic differences between humans and chimps explain the morphological and physiological differences between humans and chimps. Quite obviously, mutations can change phenotype. It also contains population specific mutations that accumulate after the two populations separate. This is an increase in genetic diversity. The alleles did not exist prior to the mutation. Go to my thread on antibiotic resistance and I will show you. We have also discussed the evidence for the mutations leading to the dark fur allele in pocket mice. If the mutation leads to a beneficial adaptation, why shouldn't it be selected for? For example, a mutation that produces darker fur that offers superior camouflage in dark lava fields. What is your evidence for this?

Then why did mutations have to occur in the mc1r gene in pocket mice in order to get mice with dark fur?Just a moment...They clearly show evidence that the dark allele was not part of the ancestral gene pool, and that the mutations appeared after the dark lava fields appeared. This is based both on selection pressures on the dark allele and on sequence variation of the m1cr alleles. You had an ancestral gene pool without the dark allele. You then had volacanic eruptions producing fields of dark lava. You then had the appearance of mutations that produced dark fur. These mutations were then selected for in populations living on the black lava.Edited by Taq, : No reason given.

Not to mention the observations of diploid species like humans. On the disease side, we see children with genetic diseases that are caused by mutations. These diseases were not found in either parent.Even more, scientists have sequenced the entire genomes of families to measure the actual rate of mutation in humans.http://www.nature.com/...f/ng.862.pdf%3FWT.ec_id%3DNG-201107And, as you mention, studies in haploid species does shed light on the issue which is why I would like to see Faith participate in this thread:EvC Forum: Application of the Scientific Method: Antibiotic Resistance

Mutations that cause disease are still an increase in genetic diversity. That issue has already been settled. The pocket mouse example is just one of many.

1. Selection pressure. They surveyed many regions across the desert spanning Arizona and New Mexico. This survey included two black lava fields (one in Arizona and one in New Mexico) separated by 750 km, the areas immediatly around each lava field, and the desert between the two lava fields. What they found is that in between the lava fields there were no black mice. Even more, there were no alleles associated with dark fur even though light fur is the recessive allele (it only takes one dark allele to have dark fur). On the lava fields, the vast majority of mice had dark fur, and the dark allele was very, very common. In the areas directly around the dark lava fields there was a mixture of the two phenotypes. Right away, one thing is very appararent. There is extremely strong negative selection against the dark allele in the light colored desert that separates the two lava fields. If the dark allele had emerged in the light colored desert it would have disappeared in just a few generations. The only way that the allele could survive is if the mice carrying the mutation moved into the black lava fields.2. Variation of the alleles. From the paper, "Finally, the pattern of nucleotide variation observed among Mc1r alleles from the Pinacate site suggests the recent action of positive selection. Thirteen polymorphic sites are variable among the light haplotypes, whereas only one site is variable among the dark haplotypes (Table 1). " This means that the dark allele had gone through a much more recent selection event than the light allele. Therefore, the dark allele emerged after the light allele.3. Age of the lava fields. As was demonstrated above, you need black lava fields in order to have the dark allele. So how old are the lava fields? Very recent, geologically speaking. They are around 1 million years old, much younger than the desert landscape that the ancestral populations adapted to. As shown by both the nucleotide variation and selection pressures, the recent appearance of the lava fields is just one more piece of evidence showing that the dark allele arose through recent mutations in a population that did not have dark fur. That is what the thread on antibiotic resistance is all about. I would love to see your participation in that thread:EvC Forum: Application of the Scientific Method: Antibiotic Resistance It is dominant, and it is immediately selected out of populations that live on the original, light colored desert that existed for eons before the black lava fields appeared. As sure as anything can be.

Why don't you think it is equal?Isn't rain equal to the rate at which water flows down a river? Can I claim that all rivers should dry up in a single year because rain doesn't exist? Afterall, once rain lands it flows downhill too so you can't get an increase in river water. They should all dry up. It hasn't? And you know this how? Have you been sequencing the genomes of every cheetah born and testing those observed mutations for beneficial effects?

How so? You have said that, but you have never brought forth evidence to back that claim. Now would be the time for that evidence. Why can't you have additional mutations after a selection process that keeps evolution moving? Why can't you have thousands of alleles all being selected for in parallel within a population while also having mutation continually producing more alleles that are passed through selection?What is stopping the continual accumulation of mutations leading to a continual change in morphology and physiology? They weren't observations. They were empty assertions backed by zero evidence. Until the next generation is born with mutations that increase genetic diversity.

To get this into the real world, perhaps you can give us some criteria to use when looking at real life genetic data.I think we both agree that humans are different from chimps because the DNA sequence of our genomes is different. You would also contend that humans and chimps are in different baramins. I think you would also contend that the genetic variation between genomes of different chimps is within a baramin.So I would like to know why the genetic differences between humans and chimps could not be produced by mutations, but the genetic differences between chimps could be produced by mutations. Can you explain why the process of mutation can do one, but not the other?Edited by Taq, : No reason given.