tag:blogger.com,1999:blog-8859456735165996893.post9078418179714798894..comments2024-03-28T02:36:04.078-07:00Comments on Health Correlator: How long does it take for a food-related trait to evolve?Ned Kockhttp://www.blogger.com/profile/02755560885749335053noreply@blogger.comBlogger12125tag:blogger.com,1999:blog-8859456735165996893.post-24563589996802163072019-09-22T14:37:00.879-07:002019-09-22T14:37:00.879-07:00This post is a revised version of a previous post....This post is a revised version of a previous post. The original comments are preserved here. More comments welcome, but no spam please!Ned Kockhttps://www.blogger.com/profile/02755560885749335053noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-80381103263097980092012-02-20T11:40:56.898-08:002012-02-20T11:40:56.898-08:00I did not know this is how long it would take to a...I did not know this is how long it would take to adapt.Viagrahttp://www.kwikmed.com/viagra.aspnoreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-82493345406188295382011-04-05T09:27:27.023-07:002011-04-05T09:27:27.023-07:00I think that the health is one of the things that...I think that the health is one of the things that every one should be careful, I think that your blog is really good!!22ddcheap viagrahttp://www.xlpharmacy.com/noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-49146095373671648832011-03-30T13:53:39.691-07:002011-03-30T13:53:39.691-07:00That translates into a selective advantage (s) of ...That translates into a selective advantage (s) of 100%. Finally, let us conservatively assume that the population is relatively large, with 10,000 individuals.viagra onlinehttp://www.iservepharmacy.com/noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-26057945382969446692010-09-10T07:00:58.605-07:002010-09-10T07:00:58.605-07:00Hi Karen.
It is possible that epigenetics plays ...Hi Karen.<br /><br />It is possible that epigenetics plays a key role in some short-term adaptations whenever no genotype that can benefit from an environmental change is present.<br /><br />After all, genetic mutations that have an actual effect on the phenotype are rare.<br /><br />But most sexually-reproducing populations have enough genetic variation to fuel short-term adaptations.Ned Kockhttps://www.blogger.com/profile/02755560885749335053noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-72211533925557898392010-09-09T22:47:33.230-07:002010-09-09T22:47:33.230-07:00Hi Ned,
It seems to me more likely that the epig...Hi Ned,<br /><br />It seems to me more likely that the epigenetics rather than the genetics are involved in short term adaption. The genes remain the same, but the expression is affected through at least several generations. You don't need to deal with mutations.. See Olov Bygren's study of families living in Overkalix. If girls were exposed to famine in utero or boys around the time of testicular development (germcell development for each sex), their "thrifty adaptation" would be passed on. If the subsequent generations were exposed to periods of plenty, they would get fat.Karen Vaughanhttps://www.blogger.com/profile/07747369799976033439noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-11225633740374037252010-02-11T06:45:32.255-08:002010-02-11T06:45:32.255-08:00Hi PaleoDoc.
Thanks for your kind words about thi...Hi PaleoDoc.<br /><br />Thanks for your kind words about this blog, which is mostly for the benefit of family and friends at the moment. Your blog is great!<br /><br />I think you are correct. A fast evolution (e.g., 396 years) of a food-related trait would not necessarily increase longevity. For example, I suspect that the ancient Inuit evolved to be adapted to their heavy meat-and-fat diet, although longevity among them was not as high as in other traditional human groups (e.g., the Okinawans). Now it is much worse, due to their westernization.<br /><br />As for Lamarck’s theory, I am intrigued by the work of McDougall (a bit old) and several others showing that indeed certain acquired traits appear to be inherited. But the counterarguments are also compelling. For example, McDougall showed that rats that learned how to solve a maze had offspring that also seemed to be better at solving the same maze. The counterargument is that those rats had genetic mutations that made them better at solving the maze in the first place, and passed those genes to their offspring – a Darwinian phenomenon.<br /><br />Two interesting factoids that are related to this: (a) Darwin’s first edition of the “Origins” contained a clearly Lamarckian argument about what he called “use and disuse” or traits, which was removed from future editions; and (b) most non-behavioral traits (e.g., metabolic, morphological) seem to be preceded by related behavioral traits (e.g., preference for a type of food), even in organisms with a very simple nervous system - giving the impression of Lamarckian evolution when what is happening is purely Darwinian.<br /><br />Finally, on your point about us becoming more diseased, I also think you are right. We as a species are most likely devolving, but very slowly and (in my view) due to Darwinian forces. In a population of billions, people develop genetic diseases all the time through stochastic mutation, many of whom survive to have children due to medical interventions, and pass the defective genes to the next generation. Selection pressures for health-promoting traits are very weak among modern humans.Ned Kockhttps://www.blogger.com/profile/02755560885749335053noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-11423890775165112752010-02-08T04:47:18.872-08:002010-02-08T04:47:18.872-08:00Hi Ned,
Many thanks for a very insightful blog, ve...Hi Ned,<br />Many thanks for a very insightful blog, very professionally looking too (unlike mine)!<br /><br />I think it is perfectly possible for a food-related trait to evolve in a much shorter time than often believed, but would that mean perfect adaptation in the sense of health and longevity?<br /><br />These are very complex mechanisms, dependent on multiple genes and one mutation (say, lactose tolerance) would not necessarily mean that milk is now otimal food (there is casein with its opiate-like activity, perhaps different composition of fats, trace elements etc). Some mutations led to adaptation, but are clearly associated with bad health, e.g. haemoglobinopathies and G6PD deficiency (malaria), cystic fibrosis (plague) and many others. I would guess that many people can live on high carbohydrate diet without being obese and diabetic due to their ancestors' adaptation, but I hypothesise that they would not be in perfect health when you look at arteries, brain, skin etc. It would take many more thousands of years to fine tune the who machinery, to switch it to a new dietary paradigm than to make food tolerable.<br /><br />But phenotype is not only genes and regulatory effects can compansate for genetic conservatism. Also, please to not ignore Lamarck completely. There may be a grain of truth in the inheritance of acquired traits, as claimed by neolamarckists based on modern molecular genetics (look at modern interpretation of Baldwin effect). But if Lamarck was right, we are not necesarily becoming better adapted, we might be getting more diseased "by nature" and pass the modified genes on. Just being devil's advocate.PaleoDochttp://paleoclinic.blogspot.comnoreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-15065245885946684992010-01-23T06:44:06.905-08:002010-01-23T06:44:06.905-08:00Hi Future Primitive.
Thank you for those links. V...Hi Future Primitive.<br /><br />Thank you for those links. Very interesting!Ned Kockhttps://www.blogger.com/profile/02755560885749335053noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-61102484731393435052010-01-22T10:15:08.623-08:002010-01-22T10:15:08.623-08:00Thanks very much for the book recommendation! Jus...Thanks very much for the book recommendation! Just added it to my shopping cart.<br /><br />You may find this paper of interest -<br />http://www.pnas.org/content/early/2010/01/06/0909000107<br /><br />I just came across it in a recent article in The Scientist titled "Ancient humans more diverse?". <br /><br />http://www.the-scientist.com/blog/display/56279/<br /><br />From the article:<br />'Modern humans have an effective population size of about 10,000 -- a relatively low level of genetic diversity. ... This estimate of 10,000 has been regarded as stable for about 200,000 to 400,000, maybe "as far back as a million years", said population geneticist Chad Huff of the University of Utah (one of the paper authors)'Future Primitivehttps://www.blogger.com/profile/17911308975444898748noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-86892299593643699112010-01-22T05:51:10.892-08:002010-01-22T05:51:10.892-08:00Hi Future Primitive.
I think you know more about ...Hi Future Primitive.<br /><br />I think you know more about this topic than I do. It seems to me that migration would tip the scale toward genetic drift if it was emigration, and toward selection if it was immigration.<br /><br />Below is a book where, I think, you can find an analytical and more elaborate answer to your question. You may know have read it already; the authors deal primarily with the evolution of social traits, taking migration and other factors into consideration. The reasoning applies to the evolution of any trait, in my opinion.<br /><br />McElreath, R., & Boyd, R. (2007). Mathematical models of social evolution: A guide for the perplexed. Chicago, IL: The University of Chicago Press.Ned Kockhttps://www.blogger.com/profile/02755560885749335053noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-40190322015446071962010-01-21T14:46:42.654-08:002010-01-21T14:46:42.654-08:00Interesting post. I've run some large user-gu...Interesting post. I've run some large user-guided genetic algorithms in the past (in parallel, on around 1000 cpus). It's a real challenge to get the GA parameters tuned - ie population size, mutation rate, etc... The choice of representation and method of genetic crossover come into play as well, of course. <br /><br />Anyway, the whole user-guided approach is further complicated because of user-fatigue. That is, how many individuals is a user willing to rank for fitness until exhaustion and frustration sets in? (it can be fascinating at first and then get very tedious!). The user's preference can be fickle and/or influenced by the ongoing simulation as well - that is, the fitness measure itself can be a moving target... The challenge, then, is to find an acceptable solution quickly before the user gets up and leaves. <br /><br />In general, small populations lack diversity and tend to rapidly converge to local minima in the search space. <br /><br />Conversely, large populations, while they have the most initial variation, might not converge towards the global minimum in an acceptable amount of time. <br /><br />A simplification in the models I've run also assumes fixed population size per generation - as you point out above, populations grow in size over time...<br /><br />Something I never got around to was to set up multiple sub-populations and occasionally migrate individuals from one population to another... <br />And that's what I'm getting at: How would the the rate of migration of genetic material between sub-populations influence the estimate you provide above?Future Primitivehttps://www.blogger.com/profile/17911308975444898748noreply@blogger.com