Haldane's Dilemma

I'd like to correct a huge mathematical error I made in Round 1 that Con graciously led slide. I carelessly presented 1,667 as being the result of [10 million years / (300 generations / 2)]. As you may have noticed, this makes no sense. Allow me to backtrack and correct myself. 10 million years = time since human lineage broke off from ape ancestor 300 = number of generations Haldane figured, on average, would be required for a beneficial mutation to become “fixed” or “common” in the population of pre-humans 20 = number of years per generation, on average 1,667 = 10,000,000 / (20 * 300) Now let me address Con's points. According to Haldane, selection pressure may result because “a sudden change occurs in the environment”, but Con argues that “in the last 10 million years, the environment has not undergone rapid changes”. However, Haldane deals with Con's objection in the next sentence: “the general conclusions are not affected if the change is slow.” Con objects, “For some reason, Haldane assumes the reproductive capacity is lowered [when] a sudden change occurs in the environment.” Haldane meant the population's overall reproductive capacity. Haldane isn't trying to say every female suddenly lost the ability to have as many offspring, only that the majority of them are now less likely to have the usual number of babies, being less fit. The few females who do posses the beneficial genes will be able to birth the same, or even greater, number of offspring, but it won't be enough to immediately bring the entire population's overall reproductive capacity back to where it was. I don't see the impact of Con's “mammal” point. Con argues “There are various issues with Haldane's substitution cost. One is that as population increases, the cost should go down.” This is simply not true. For example, imagine a population of 10 gorillas. 4 of them are pink. For the next generation to have 5 pink gorillas, the cost is a reproductive rate of 1.25. Now, take a 2nd population of 500 gorillas with 4 pink ones. For the next generation to have 5 gorillas, the cost is still a reproductive rate of 1.25. Con says “the cost does not account for sexual recombination, which causes fixation faster”, failing to realize that Haldane actually did account for recombination. Con's objects, “it doesn't account for simultaneous changes. Here, if two good changes were approaching fixation, and an organism without either dies, it would have died for two changes, not one. Therefore, the cost would be halved[...]” This is irrelephant and has no bearing on the cost. Even if an individual lacking 2 good traits dies, it won't increase the reproductive rate of those that do have the new traits. Con says “Just because an organism has a higher chance of survival with a new gene does not mean that all the others will suddenly become less adapted to the environment. Their chance of survival remains constant, and this is not represented in Haldane's work.” Let's assume this is true for just a second; it wouldn't damage my case in the slightest! If those individuals without the new trait maintain their fitness, instead of losing it, it only hurts the chances of the new trait getting substituted into the whole population, since those without the new trait are being stubborn and slowing the substitution of the new gene with their own old-fashion genes. Competition among members of the same species exists, so some members gaining fitness may result in a loss of fitness among other members. Con says “His '300' number that my opponent used in his argument is not backed up by any calculations. Haldane says, "I think n=300... is a more probable figure." He does this to generate in his calculations a low intensity of selection.“ Con is not just incorrect, he contradicts himself. Haldane is not trying to account for low intensity selection, but moderate intensity selection: in other words,realisticselection, although he does point out that his estimation allows for periods of strong selection pressure (“DISCUSSION” on page 20). Con's self-contradiction lies in the fact that here, he's claiming Haldane's number is not reasonable because it favors low intensity selection, but previously, Con tried to discredit Haldane's calculations by arguing Haldane favored strong intensity selection: “the environment has not undergone rapid changes [like Haldane says], such as a meteor strike or massive volcanic eruption. It has remained relatively constant”. So Con is trying to undermine Haldane's paper by suggesting selection is less intense than Haldane thought, yet more intense than Haldane thought. Con goes on, “There is absolutely no definitive scientific reason why the number should be 300.” Maybe Con didn't read page 20 of Haldane's paper. Yes, 300 generations per fixation is an estimate, but Haldane showed the math he used to justify this number on page 20. For example, he argues 43 generations per fixation is intense selection, and rare, such as what happened to the Peppered Moth. If Con likes, he can propose a number greater than 300 number (which would help my case immensely), or a smaller number. His choice! “The obvious problem here is that 300 comes from nowhere. “ This is simply not true, and again, I urge Con to read page 20 of Haldane's paper. Con says “Haldane assumes that changes due to genetic drift and gene changes happening simultaneously are uncommon in evolution and does not account for them in his assessment.” I'm not sure how Genetic Drift is relevant. Genetic Drift is, by definition, random, and Con provides no reason for us to think the randomness of Genetic Drift would hurt my case, instead of being neutral or even favorable towards it. Con says “simultaneous fixation is, in fact, extraordinarily common. This occurs when certain genes are fixated at the time. Due to sheer amount of nucleotides, this is very common, and often occurs with more than one nucleotide. However, Haldane completely ignores it, even though it would greatly change the outcome.” I'm not sure why Con brings this up, since it's completely neutral to both of our cases, just like Genetic Drift. It seems Con is aware of this, since he said “it would greatly change the outcome”, making sure not to claim it would sway the outcome in any specific direction. Simultaneous fixation of nucleotides can happen for both favorable, neutral, and harmful mutations. Additional Arguments Con says “Genes are not passed down individually[...] recombination is more efficient. This means that some 'meaningless' changes would be passed on with the same efficiency as 'good' ones.” This is not relevant... at all. I'm not sure how meaningless changes sway the facts in Con's favor. Con says “Even if we assume that Haldane is correct, 1667 may be enough nucleotides to cause a difference.” Considering that we differ from chimpanzees by 35,000,000 nucleotides, this isn't even slightly plausible.(2) Perhaps my own mathematical mistakes hurt my case more Con's actual arguments. I await Con's rebuttals. (2) http://genome.cshlp.org...