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Everything posted by jp255

  1. It is inappropriate to label the trait "bad" because no where in that sentence is the mean fitness of individuals with said "bad" trait compared to the mean fitness of individuals without said "bad" trait. Post 25 was lost on you. Anyway, you need to support that statement with evidence that shows partner choice/reproduction was already biased (and not variable within the population) towards the "bad" trait before the "bad" trait rose to fixation/high frequency as this is practically the only way such a bad trait can rise to fixation (the survival impediment of the "bad" trait would be more than corrected for and instead be positively selected for). Essentially, you'd have to show that the biased "bad" partner choice is free from selection (because it cannot vary in the population) itself because in your scenario it would have been selected against and eliminated early on. In a nutshell, it requires much more than "this bird has an excessively large tail, it is bad" to actually label it as bad. Indirect genetic benefits must be considered, which is what post 25 shows an example of. look up the handicap principle. Non-uniform fitness does exist within populations, and evolution can take advantage of anything that is associated to above average fitness individuals.
  2. Civilization changes like that can only be under local selection (one state/country/county) if the civilization change alters the reproduction/survival rates of a proportion of individuals in the population (less than 100%). On a global scale (when considering humans as one big population) civilization changes could potentially contribute to natural selection, if civilization contributes to reproductive/survival variance among countries. For example, if civilization places a limit on reproduction (1 child only), and other countries are reproducing at a greater rate then this contributes to allele frequency changes (and is a selection pressure) when considering human populations as a global population (and assuming survival rates are the same). Basically, anything that contributes to population variance (on global or local population levels) in average number of children that reach reproductive age is under selection. It is, for the most part, speculation as to what factors contribute.
  3. The discussion is still related to the evolution of the eye. NIF is just expressing his opinion, that evolution is flawed and cannot explain the formation of the eye structure. My take on your point of view is that you are not to be taken seriously, but not for the same reason as iNow. You seem to think that evolution is flawed and can't explain the formation of the eye. So in your eyes, evolution is a belief. To you, there are two theories which have just as much liklihood of being true as each other. So, why do you choose to place more value in one than the other? Are they not just as likely as each other? This reasoning leads me to believe that you are biased. There is no point discussing the counter arguments with you in 2 weeks time because of this. Your argument for evolution being unable to explain eye evolution can also be ignored.
  4. What better way is there to get your theory to someone who is open-minded than to spread your theory everywhere and anywhere you can? It would likely reach said person faster if you took this approach rather than keping it to yourself, no?
  5. What would you offer as evidence for a creation explanation for the eye structure?
  6. Dmaiski was just pointing out that germline mutations are the only relevant mutations when evolution is considered. Still, I'm not sure how significant that argument is. I'd imagine the mutation rate increase from such factors to be fairly low.
  7. jp255

    Gay gene

    Post 115 has a lot of trash in it. Assumptions. you must explain why you are making them. Why must a homosexuality contributing genetic factor be specific to homo or hetero individuals? why must it be limited to the Y chr? you are, again, not considering all the possibilities and are wrongly eliminating potential possibilities with no reasonable justification. You do this often. Be more critical of your own ideas. independent of genetics, really? all mental circuits are based on experience and after birth? No, your incorrect opinions are not evidence against the heritability studies. Try again. Can you alter who you are attracted to freely? by changing the features that you find attractive. For instance, you decide to include eating habits into the decision process, like whether or not someone likes jam. You come across somone which you previously thought was attractive (based on different traits), is now not attractive because they don't eat jam. Using your own analogy. Can you change your mental patterns, such that you are attracted to someone only if they have a hitchhikers thumb? If you can't then you do not have complete free will over your own attraction. Can you freely change the traits that you find attractive? Can you turn off the attraction, and not be attracted to someone you previously thought attractive? If you still fail to see the argument, then i'll leave you to be deluded by the illusion of free will (concerning sexual attraction). You keep harping on about homosexuality being mental. this falls under the environmental factor and genetics category, and how it must be the cause. Those are the only two categories which can affect variance of traits in a population, mental arguments are not a third category. They are present in the heritability studies and their effects are contributing. They do nothing to reduce the validity of the conclusions of those studies, that 30-60%ish is genetic and the rest environmental. So you should be saying that they are the factors which contribute most.
  8. I'm not really sure what you are getting at, but I know that traits have varying fitness depending on the environment. That is obvious. Post 25 was lost on you because you are still going on about bad sexual traits. Show me evidence that they are bad. Pointing out the obvious handicaps of the traits is not enough to categorise a trait as bad. That is what post 25 is saying.
  9. You still have not answered the question. What is your explanation? View point 2 is merely a rejection of the view point 1, which is an explanation. So if you reject that explanation, how do you explain it? What assumption?
  10. The purpose of post 25 was to make you ask yourself, but are they really bad traits, or can they be good? There are many sexually reproducing species which you would say had bad traits as a result of sexual selection. Do you really think that natural selection would allow such bad traits to fixate in such a large number of species if they really were bad? sure it can happen, but in so many instances that you see today? what are the chances? Overall it is a good trait in the long run then. Survival is only one aspect of evolution, reproduction is just as critical. So you should be asking yourself, what is the net benefit or loss of fitness. Rather than down playing the importance of reproduction.
  11. jp255

    Gay gene

    I couldn't understand the metaphor! Anyway, at least you understand the influence of the brain in the decision process. This is why I think it is like an illusion of free will, because you have the choice but the choice you make is biased in the sense that you are more likely to choose one option than the other based on a range of factors. Prejudice probably helps people realise this, and the lack of it means heterosexuals are likely to be the ones to say it is free will. Yeah, one that has a genetic and environmental basis. So what if it is mental? every trait's variance is explained by genetic and environmental factors (just differring levels of contribution).
  12. View point 2 is not an explanation. It is merely a dismissal of view point 1. So the question as to what is your explanation is, is still unanswered. What is it which you specifically disagree with about the theory of evolution? you posted in the current human evolutionary pressures thread which I find a little odd. Does this mean that you think natural selection is likely? but you disagree with the evolution of complex traits which you criticise due to irreducible complexity? Do you disagree with the concept of speciation as well?
  13. jp255

    Gay gene

    Reasons why it is unlikely to be a choice: 1. sexual attraction/partner choice is not random, with a strong bias toward toward beautiful individuals. If you are arguing that it is a choice, then you should be able to fully explain and justify your own sexual attraction and completely explain your own preference to all traits (eye colour, weight etc). It it is a choice, you should also be able to make yourself be attracted to anyone of the sex you are attracted to, no matter how ugly they might be. If it is free will sexual attraction should be able to be turned on and off as easily as a light switch. Only then is it reasonable for you to claim it is free will, if you possess these abilities then I can understand your reasoning. If you fail to be able to fully account for your own sexual attraction then how do you expect someone who is gay to be able to control their attraction? I argued about this earlier, you can mine back to find it. 2. the heritability has been estimated numerous times, and meta-analysed. Not going to go into it, just to say that there is a genetic and environmental component to explaining an individuals sexual orientation. Please justify why you know that homosexuality is a choice. That it is not possible for it to be out of the individuals hands. If anything, you should really be more inclined to think that sexual attraction and orientation are not a choice. Anyway, for what reason would someone choose to remain in a category which is subject to prejudice if it is so easy to so freely choose to revert sexual orientation? Personally, I think some do choose, but others don't. I also think that sexual attraction/partner choice is an illusion of free will.
  14. Sexual attraction results in non-random mate choice. As a trait, sexual attraction will only increase in frequency if individuals which display non-random mate choice have a significantly greater number of offspring that reach reproductive age (or by fluke genetic drift). There is a difference between this and your statement. It is that sexual attraction can be selected for itself because it can increase the probability that an individual will mate with a fit partner (higher fitness than population average). It can, but not always, rise in frequency because it allows for detection of non-uniform population fitness so reproduction can be limited to partners at the high end of the fitness distribution (occurs when sexually selected for trait is associated with higher fitness). An example of such an occurence is found in this paper Call duration as an indicator of genetic quality in male gray tree frogs. Science 280: 1928-1930 on this site http://www.unc.edu/~welcha/ . I couldn't find a direct link. The link is an example of this possibility I described. To show it in humans is next to impossible, fitness is not so applicable to humans anymore and this is complicated to determine. It would have to be shown back when we were hunter gatherers to provide evidence of sexual attraction providing fitness benefits to offspring, this is practically impossible. Non-random and non-uniform sexual attraction can be shown however, at least showing the possibility for biased mate choice in favour of fit individuals is there. Considering the stuff above, to say that sexual traits are more important than useful traits is stupid. There is also the possibility that sexual attraction to individuals with these traits might have occured, and this can't really be denied. TLDR: you might think that the trait serves no beneficial purpose, but if it is associated to fit individuals then the opportunity for sexual attraction to be positively selected for (and therefore useful) is there. A sexually selected for trait shouldn't be termed "not beneficial" until it is found not to be associated to fit individuals. Sexual selection can be greatly advantageous if a trait that is highly associated to fit individuals is found.
  15. I am not so sure that some of these traits actually are under selection. It is fair to say that survival to reproductive age is not of much of a selection pressure to human populations (first world of course). So genetic factors which contribute to increased survival won't be under much selection, as the probability anyone individual in the population reaches reproductive age is already very high. Therefore any strong natural selection going on is likely to be occuring on factors which affect the number of offspring an individual has. So I am doubtful that those traits are under selection. You could argue that these might be under sexual selection, but sexual selection in humans going on today is not just about mate choice anymore (because contraception use is commonplace) but rather who you decide to have children with. Basically, physical beauty could only really be under selection if attractive people have more children than the average individual. For this reason, I am not so sure there is much sexual selection currently going on. I think that the most likely factors under selection today are those which contribute to population variance in average number of children an individual has. Some people do not have children despite being fertile and heterosexual, any factor contributing to this behaviour will be selected against. Vice versa to those that have more children than the population average. These factors can be genetic and environmental (culture and civilisation can be under selection).
  16. I was arguing against post 17 and I am arguing against some other arguments of yours in post 19. Truth be told I skipped over that quote, I didn't really get the first half of post 15, and I was under the impression that you were still skeptical about sexual reproduction being a better method for evolution from #17 and 19. Ok, if your onboard with sexual > asexual. Then respond to my previous post where I criticise your thinking on sexual attraction and inefficient traits that you think sexual reproduction produces (that asexual does not).
  17. This isn't relevant. You were questioning what I meant by sexual is better, and you provided examples of bacteria being more diverse. I then was trying to point out to you that before humans/animals even get the chance to change once, bacteria would have already had the opportunity to evolve a lot. average generation time for human 20-25 years? average generation time for bacteria: 2-3 hours? It is likely that sexual reproduction is a more efficient method of evolution than asexual reproduction over a set number of generations. That is what I've been arguing for. Except you are not considering all the possibilities. You calling a trait which increases an individuals' chances of reproducing "bad". This trait will be positively selected for, because it it increases reproductive success. Also, how do you know that sexual attraction was not under positive selection itself? that it is selected for because individuals that survive to reproductive age that possess traits that lower their chance of survival means that they are fitter than an individual without such traits. In other words, how do you know that sexual attraction did not rise to fixation to take advantage of non-uniform fitness of potential mates in the population. If you had considered this possibility, then these traits are considered good. Natural selection isn't confused about what is good and what is bad, any trait which increases survival/reproduction is good and will likely rise in frequency and vice versa. Again, everything about these scenarios suggests that actually these traits are good, because they have evolved and survived for long periods of time and increased in frequency. Read my previous explanation again? elimination of a trait in explicit asexual populations is death or freak mutation reversion, in a unicellular species with short generation time this is not costly, nor in a multicellular with short generation time. The cost of elimination of a trait for an explicitly asexual population with a very high generation time of years is a lot higher, whereas the cost of elimination of a trait in a sexual population with very high generation time is not as high. Do you agree that generation time and the rate of evolution are related, at least in multicellular species that rely on germline mutation to evolve? If you do then you should expect sexual reproduction to be more efficient because most species with high generation times of years explicitly reproduce sexually, and there almost none which explicitly reproduce asexually.
  18. The number of generations it takes for a gene to become optimised. Essentially, the ratio, number of generations spent evolving:fitness increase of a gene. This accounts for the extreme variation between species' average reproductive age. Have you ever calculated the number of generations a bacteria can reach before the average human reproduces once? and have you ever calculated the number of offspring one bacteria can have before the average human can have one? and finally, ever calculated the number of tested mutations (natural selection would have already acted on them) that have occured within the bacterial offspring before a human even gets the chance to produce one offspring with around 60-120 mutations? This is the major weakness of your argument which compares mammal adaptions to bacterial adaptions, you are not taking into account this extremely large difference! We might have had the same amount of time to evolve since the last common ancestor but have we had the same number of generations as bacteria since then(and therefore same number of germline mutation opportunities)? This could also partly explain the difference in observed diversity can it not? You're comparing apples and oranges, it is meaningless to say bacteria are more diverse than mammals when this difference of evolutionary potential is not accounted for. This is what I am arguing for, that exclusive sexual reproduction is more efficient in terms of evolutionary potential than exclusive asexual reproduction after taking into account average reproduction age/number of generations. It is more likely to be efficient because of the reasons I stated in an earlier post. In order to quantify the magnitude of difference between the evolutionary potential of each reproductive method, a mathematical model is required, but this is only an estimate as big assumptions have to be made for the sake of simplifying the problem. That sentence contains a big error. You cannot say that a bad trait "ignores" natural selection. Traits which contribute to differential survival/reproduction (you said "bad" traits) will rise or fall in frequency, this is natural selection. Therefore the example you use occured due to natural selection. Physical attraction itself is under selection. Your argument could be an advantage for sexual reproduction anyway, because physical attraction might have biased reproduction towards the fittest individuals. If you still stand with your claim that natural selection is ignored and bad traits rise to high frequency despite them being bad in sexually reproducing populations, then how do you propose the traits became so prevalent?
  19. The aspect of evolution that should be considered for this debate. Differential rates of survival and reproduction between individuals. This is all that is relevant, anything which does not contribute to differential rates of survival or reproduction will not be under selection and instead will be under genetic drift (if it is a genetic factor) or will not have any effect on evolution (if it is an environmental factor). Survival rates are relatively high, in first world countries at least. Medicine has played a big part in this, and the selection pressures against disease causing alleles is small (for diseases with effective treatments). It is fair to say that some genetic diseases (with very effective treatments) have low selection and are pretty much under drift. Does natural selection act on civilisation? I think it does. However I think it does so by, non-genetic mechanisms, by culture. When I say non-genetic I understand there are obviously genetic requirements before culture can arise, I mean that the variance observed in people's taking to the culture is primarily enviornmental rather than genetic. In other words, if there were a heritability study on culture it would probably be mostly explained by the environment and the value for genetic contribution would be low. This is only a suggestion, but I think it is likely because I don't think that condom use is genetically programmed, or that celebrating birthdays is programmed, or that most/if any traditions/cultural behaviours are genetically programmed. This area of study is known as memetics, where a meme is thought of as a "unit of culture" that is heritable but not constrained to DNA/replicator. For example: let's consider religion and it's potential to contribute to evolution. Can natural selection work through religion? I think it can primarily through the reproduction aspect of natural selection. Last I checked some religions don't agree with use of contraceptives, I apologise if this is wrong. In comparison to a culture where this use of contraceptive is commonplace, and assuming that every other factor is the same, this religion/culture should in theory lead to a significantly higher rate of reproduction amongst those who do not use contraceptives. Thus the idea/culture of religion (and not using contraceptives) is subject to natural selection, however this assumes it must be able to survive or be heritable. In theory an idea such as this (not using contraception) does lead to natural selection (in a poipulation where some people do not use contraception and some do), when one assumes that the idea is heritable, and that all other factors are equal. The idea itself will be overrepresented in the population and gradually rise in frequency and also the genes of that person will be overrepresented in the population and rise in frequency. Proving it in reality is obviously difficult, there are so many other factors at play. The potential for civilisation/culture/religions to cause gene frequency changes by altering reproduction rates (and also survival) is there though. There are genetic requirements, but I think that the genetic contribution to individual variance regarding cultural type behaviour is very small. Imagine a heritability study regarding the culture of not using contraception. MZ and DZ twins that grow up in families which are not pro contraception, what do you think the discordant rates will be? do you they will differ by a large amount between MZ and DZ? That genetics can partly explain why one twin decides condom usage is bad and the other doesn't? I'm not so sure genetics can explain much of an individuals opinion.
  20. I'd be careful when saying that sexual reproduction is more sensitive to negatively selected mutations than asexual reproduction. Sexual reproduction allows for the loss of harmful mutations because only 50% of an individuals genetic material is passed on to offspring, whereas asexual reproduction does not allow for this as 100% genetic material is passed on. Also, you should completely ignore humans and domesticated animals when you think about this because medicine severley reduces the selection pressures that would be faced in the wild. In the wild when there is high selection against deleterious alleles, it will not take many generations to get rid of. Also, Sexual reproduction can unlink negatively selected alleles from positively selected alleles that are on the same chromosome by recombination. Now consider this scenario. A positively selected mutation and a negatively selected for mutation occur on the same chromosome, assume that the individual is fit enough to reproduce. In a sexually reproducing population, the mutations can be unlinked from each other, but in an asexually reproducing population they can only be unlinked by a freak mutation reversion. Overall it is easier for a sexually reproducing population to unlink bad and good mutations. Except sexual reproduction is (currently) better than asexual reproduction, overall. Does this mean that asexual reproduction cannot be better though? Just because a particular feature/trait might be prevalent/fixed in a species does not mean that it is the best possible solution. Maybe maths can give an answer to this question someday.
  21. jp255


    There is a positive correlation between the vigor/health of most organisms and heterozygosity, the term to describe this is heterosis. It is most widely accepted in plants. The data supporting heterosis in humans is not so strong as it is limited to a a small number of traits, so at best it is suggestive evidence at the moment. That being said a number of papers have found significant differences between inbred and outbred individuals, an example of such a paper is this one by H. Campbell et al. (2006) http://hmg.oxfordjournals.org/content/16/2/233.long The negatives of inbreeding are well known in a number of species too. So I definitely wouldn't support a consanguinous marriage or inbreeding in general, as there is evidence to suggest that it could lead to children which are unhealthier. The whole ethical issue. I consider it unethical, but there are other issues which annoy me more. The issue that other diseases, such as Huntington's disease, are still prevalent today (at a higher frequency than I would like) and they are not considered unethical as far as I am aware. If they were considered unethical, and people that know they have it or if they don't but know there is a chance they could, then it would not be a prevalent as it is. The prevalence would purely be due to de novo mutations. I remember not so long ago there was a story in the news about people smoking around children (the children had breathing difficulty or something), the way it was presented suggested that it was not unethical. There are many things which are unethical, but are clearly not considered to be unethical. It is like Derin said. Dominant genetic diseases can be eliminated from populations much faster than recessive traits by natural selection. So this can explain a high number of recessive conditions being present in the population at any one time. Also it is a lot easier for recessive alleles to hitchike to high frequency, and they can provide heterozygous advantage and therefore be subject to balancing selection, Derin provided the malaria example. It could also be that more genes are haplosufficient rather than haploinsufficient.
  22. This is to our current knowledge. There could be a better definition yet to be discovered without natural selection/evolution, but currently without it's inclusion there are examples of self-replicating systems such as peptide self replicators which would end up being defined as life. Personally, I think natural selection/evolution is one of the core descriptions which is unique to life. Everything is essentially made up of non-living material, and natural selection/evolution is one of the best descritions which can exclude many natural chemical systems that would be called life if other criteria were used, such as self-organisation, metabolism etc.
  23. I am assuming you tested the primers and know for sure that they work. Try lowering the extension temperature? That cured the problem I had not too long ago. I was trying to PCR a fragment which was particularly AT rich, at higher extension temperatures I think that this AT rich part melted and didn't amplify. Extension worked at 58 in the end
  24. many bacteria do not exclusively reproduce asexually. Very few species in general reproduce exclusively by asexual reproduction. You think that there are less species that exclusively reproduce sexually than there are asexually? There probably is data out there to show, I have not looked to be honest. I should have included "exclusive" in my earlier post in this thread When I argues about this in the other thread, I limited the argument to animals. Should have done the same here to avoid that issue. I was primarily discussing the evolutionary potential of each, only in theory though. The correlation bit at the end is most likely true, of course I am again assuming, but there probably is data on it somewhere.
  25. The benefits of sexual reproduction over asexual reproduction are plentiful, and the ones you missed are the most important. I am strictly comparing organisms which exclusively reproduce asexually to those which exclusively reproduce sexually. There are numerous organisms which carry out both types of reproduction. The biggest advantages of sexual reproduction are meiotic recombination and the contribution of alleles from two individuals, 50% of the individuals genetic material is not passed on to any one of it's offspring (ignoring mtDNA), selection of a mate. Meiotic recombination and loss of genetic material are linked. Many advantages of meiotic recombination are lost if all information is passed on, there is no point in shuffling the allele order of a chromosome if everything is passed on. Consider the example below: Two populations of 2000 individuals, pop A is asexual and pop B is sexual. pop A and B are the same organism and have same genome, just hypothetically considering the differring reproductive methods. In each pop, three individuals have positively selected for alleles allele x, y and z, which are not the alleles of the same gene and are single point mutations. In pop B the three individuals carrying x y and z are more likely to survive and pass on their genes, but, there is also the chance that x, y and z might land on the same chromosome or in the same individual by either meiotic recombination or contribution of genes from two individuals (the three individuals reproduce with each other or offspring reproduce with each other). Individuals possessing x y and z will increase in probability with each successive generation as natural selection acts and x y and z are overrepresented, This probability is higher than asexual (and possibly rises in a non-linear manner, even after accounting for inheritance patterns). In pop A the three individuals carrying x, y and z are more likely to survive and pass on their genes. There is a minute chance that x y and z land on the same chromosome or in the same individual, the probability that this happens is the chance that the single base in gene x y and z mutates to the correct base that makes allele x y and z (this can only initially occur in the three individuals. very low probability. increases in probability over generations at a linear (I think) rate). So pop A does not have the capability to transfer the positively selected alleles present in the current population into one individual, it relies on all beneficial mutations occuring independently in one genome (sometimes the mutation might have occured before in other individuals, but it has to occur again to see both mutations in on individual so there is redundancy), so evolution occurs in a step-by-step manner (one good mutation after another, possibly two or more good mutations in one generation but unlikely). In contrast, Pop B has the capability to transfer the good alleles present in the population to one individual/chromosome and the liklihood that this will happen will increase over the generations at a greater rate than pop A(as the allele frequencies rise, the liklihood they will converge into one chromosome/individual increases). This also leads to reduced variability amongst pop A in comparison to pop B. Sexual reproduction has the potential to accumulate more positively selected for alleles in one individual/chromosome more rapidly than asexual reproduction. Selection of a mate is another mechanism which greatly benefits sexual reproduction, because it allows two fit individuals to reproduce with each other, and again there is the chance of positively selected for genes landing on the same chromosome/individual. Selection of mate is also non-random on two levels in that only the fit survive, some individuals are not fit enough to survive up to reproductive age and die. This means that each individual in the population has a certain probability of reproducing with all other individuals of the opposite sex in the population (which is 0 for the ones that die before they reach reproductive age), and so it is non-random. The other way in which it is non-random is by preference genes, I won't go into that in detail but it makes the probability of reproducing with all individuals that survive to reproductive age to also be non-random and vary. I would be willing to bet there is a very high correlation (approaching 100%) between high average time interval between generations (or average age of reproduction) of species and sexual reproduction, and also the correlation will breakdown as the time value falls as the benefit of sexual reproduction can be given up without hindering the species' capacity to evolve due to low generation times. If this is true, it suggests sexual reproduction is better than asexual reproduction for evolution. TLDR: I believe it has been mathematically shown that sexual reproduction is a better evolutionary method. I don't know any links and have not researched it however, just a guess (read it in a book).
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