Potential falsifications of the theory of evolution

Click on the "Search" link at the top of the page. For "Search Terms" enter "genetic drift" between double quotes. For "Search Forum or Category" select "Search All Open Forums". For "Search by Author Name" enter "Percy". Click on Search. Peruse the results going back to 2001. Evidently I've been familiar with the term for a long time.Now change "genetic drift" to "Kimura" and repeat the search. Peruse the results going back to 2002. Evidently I've been familiar with Kimura's work for a long time, too.So since I'm familiar with genetic drift and Kimura, you must have misunderstood my answer. Where you've gone wrong is that you've forgotten what you're defending. Back in my Message 104 I quoted Sanford, saying:

Let me explain the contradiction again. Sanford says these mildly deleterious mutations are "too subtle" individually to be subject to the natural selection filter, and that they accumulate over time and degrade fitness. When deleterious mutations have aggregated to the point where they degrade fitness then this aggregation is not "too subtle" to be subject to natural selection. Natural selection would operate against aggregations of deleterious mutations degrading fitness.

Sorry if I wasn't clear. Of course climate change of any sort affects selection. The scenario was supposed to be one of rapid climate change within a single generation, causing previously advantageous traits like hairlessness to become deleterious. Let me illustrate this another way. Say you transported hairless creatures from the desert to the North Pole. Their advantageous alleles for hairlessness would suddenly be deleterious. What is advantageous or deleterious is often a function of environment.

The point I was making is that genetic processes will not cause aggregations of deleterious mutations to spread throughout a population and degrade fitness. Natural selection would operate against this. And if you want to argue that such aggregations have too subtle an effect for natural selection to operate on, then since there is no effect on survival to reproduce there cannot have been any degradation in fitness.

Although both processes drive evolution, genetic drift operates randomly while natural selection functions non-randomly. This is because natural selection emblematizes the ecological interaction of a population, whereas drift is regarded as a sampling procedure across successive generations without regard to fitness pressures imposed by the environment. While natural selection is directioned, guiding evolution by impelling heritable adaptations to the environment, genetic drift has no direction and is guided only by the mathematics of chance.[20]As a result, drift acts upon the genotypic frequencies within a population without regard their relationship to the phenotype. Changes to the genotype caused by genetic drift may or may not result in changes to the phenotype. In drift each allele in a population is randomly and independently affected, yet the fluctuations in their allele frequencies are all driven in a quantitatively similar manner. Drift is blind with respect to any advantage or disadvantage the allele may bring. Alternatively, natural selection acts directly on the phenotype and indirectly on its underlying genotype. Selection responds specifically to the adaptive advantage or disadvantage presented by a phenotypic trait, and thus affects genes differentially. Selection indirectly rewards the alleles that develop adaptively advantageous phenotypes; with an increase in reproductive success for the phenotype comes an increase in allele frequency. By the same token, selection lowers the frequencies for alleles that cause unfavorable traits, and ignores those which are neutral.[21]In natural populations, genetic drift and natural selection do not act in isolation; both forces are always at play. However, the degree to which alleles are affected by drift or selection varies according to population size. The statistical effect of sampling error during the reproduction of alleles is much greater in small populations than in large ones. When populations are very small, drift will predominate, and may preserve unfavorable alleles and eliminate favorable ones (this means purifying selection has a stronger effect in species with a larger effective population[22]). Weak selective effects may not be seen at all, as the small changes in frequency they would produce are overshadowed by drift.[23]In a large population, the probability of sampling error is small and little change to the allele frequencies is expected, even over many generations. Even weak selection forces acting upon an allele will push its frequency upwards or downwards (depending on whether the allele's influence is beneficial or harmful). However, in cases where the allele frequency is very small, drift can also overpower selectioneven in large populations. For example, while disadvantageous mutations are usually eliminated quickly in large populations, new advantageous mutations are almost as vulnerable to loss through genetic drift as are neutral mutations. It is not until the allele frequency for the advantageous mutation reaches a certain threshold that genetic drift will have little effect.[21]Most mutations have a clear negative selective effect and cause the gametes that they occur in to disappear after a few generations. It is possible to calculate how many percent of each generation will be removed by such mutations. The size of the remaining population, is said to be a factor f0, the equilibrium frequency of non-deleterious alleles, times the total population (f0 is between zero and one). When a neutral mutation spreads by drift in a population, some of the occurrencies will be removed because they are linked to such negative mutations. That is, they are located in chromosomes that are removed because of selection against a mutation in another part of the same chromosome. As a consequence, the effective population size is reduced by the factor f0. This means that mutation and selection in combination, causes the drift to have more effect. Because strength of genetic linkage varies along the chromosome, effective population size, and thereby genetic drift, also varies. With a higher recombination rate, linkage decreases and with it this local effect on drift.[24][25] This effect is visible in molecular data as a correlation between local recombination rate and genetic diversity,[26] and negative correlation between gene density and diversity at noncoding sites.[27]

Great! Then if you are familiar with these theories, then you are aware that Ohta's refinements in the nearly neutral theory of molecular evolution are well accepted by today's population genetisists.

My job is in the "science" world.

AlphaOmegakid writes:I was trained in college for a scientific field. I was employed in a scientific field when I graduated. And since that time, I have been managing a company that produces products for a scientific field. I also have been published in a scientific publication. Does that make me a scientist?

AlphaOmegakid writes:I am a 46 year old President of a small company.

Great! Then if you are familiar with these theories, then you are aware that today's population geneticists think that creationists are talking crap?

You even brought your own rope.
You actually quoted and highlighted your source saying: "When populations are very small, drift will predominate".This is just embarrassing. It's like watching someone hang himself in public.

Dr. Sanford is an accomplished modern population geneticist. He proves your claim wrong. False.

Actually this supports my position. Please explain why you think the contrary.

Dr. Sanford is an accomplished modern population geneticist.

Care to tell us what pop. gen. work he has published in the last 20 years? The only thing I can find that comes close, and not very close at that, is a comparison of different Raspberry cultivars.

Bear in mind that molecular genetics, i.e. the biolistic method of introducing genetic material, is not the same as population genetics.

I'm also not sure that what everyone else in this thread is talking about a lot is population genetics, in terms of long term patterns of ancestry it is mostly comparative genetics that is more relevant, although I understand that as sequencing technologies improve the 2 fields are converging to some extent.

The fact that someone more knowledgeable than you finds your gibberish downright embarrassing to read ... supports your position?Perhaps you could explain why. Or perhaps you could post more gibberish. Only time will tell, although I believe that I can guess.

Im not sure of your reasoniing here. Dr. Sanford is a Biologist in the field of genetics who specializes in agriculture. Everything in agriculture is realted to populations.

You are, of course, wrong.

This fish don't bite on that bait. This fish bites on intelligent arguments. I doubt there will be any forthcoming from the Doc.