chadn737

The hell you did: Overtone: You state right there that our need of Vitamin D, C, salt, water, iodine, etc are poorly matched to continental North America. The only reason they could be poorly matched is if these were somehow lacking in the environment. And then earlier you restated it, even though you edited your post and erased the claim. Fortunately, at that point I had already replied, so I can still quote exactly what you said: So you made this exact claim in two posts, one of which you edited after the fact to hide, the other is still very much in existence so that we can all see that you did indeed make these claims. Its obvious what I am arguing. You made the claim that North America is somehow lacking in what we need metabolically. When challenged on the fact, you have tried to hide it and claim otherwise.

In small populations, the ability of Natural Selection to eliminate deleterious alleles is greatly weakened except in for those that are strongly deleterious. Genetic Drift will predominate for slightly and even intermediately deleterious alleles and can easily drive such alleles to fixation despite being harmful. The accumulation of such deleterious alleles within the population lowers the overall fitness of the population and without some counterbalancing inflow of beneficial alleles, leads to what is called a "mutational meltdown" and eventual extinction of the population. Its actually quite common amongst endangered species today and a major concern in conservation biology. It is really not feasible to start off with a population of only 2 individuals. For one, even though the chance of a male/female is supposed to be 50/50, at such a small population, it is very common to have skewed sex ratios that would also be a significant limitation.

This is complete unsupported nonsense. Are you saying that sunlight is not available in North America? However do hundreds of millions of people live on this continent without massive Vitamin D supplements? Never mind that the Inuit, with a diet of vast amounts of fish obtain sufficient vitamin D from the frozen North. The temperate climates of North America provide similar amounts of sunshine to those of Europe and Asia, environments to which people are well adapted to receiving plenty of Vitamin D. In the Southern parts of the continent, which are tropical or nearly so, there is sun galore. As for vitamin C, we lost this ability long ago, even as other species living in continental Africa retained it. Yet we have obtained sufficient vitamin C throughout Europe and Asia, lands which we also evolved to adapt to. North America is not deficient in vitamin C providing plants. There are plenty and Native Americans were not exactly known to die of scurvy. Seriously, where the heck did you come up with this idea? REALLY? How about the claim that North America is lacking in Vitamin D, Vitamin C, Salt, and even WATER. Not only are these claims ridiculous, but they are the sort of ridiculousness that demands support. Hahaha. I enjoy you Overtone, not for your humor, which is decidedly lacking, but for the shear obstinate refusal to provide any scientific credibility to any claim you make. You are a champion of pseudoscience.

Light skin is not the same as albinism. Albinism is typically a single gene trait resulting from a mutation in tyrosinase. In contrast, white skin color is a complex quantitative trait controlled by numerous genes. Secondly, blond hair color is not related to skin color. Blond hair is actually quite common in some Aboriginal populations of Australia, the Solomon Islands, and this region of the world. The most prevailing theory is that white skin is an adaptation to more Northern climates, allowing for increased Vitamin D production in the body. While lacking in Inuit populations, the Inuit diet also consists primarily of fish, and so is already rich in Vitamin D. There is not really any evidence that white skin is itself due to sexual selection, although this has been suggested in the case of blond hair.

If a colony will only grow if supplemented by a nutrient, that tells you that it can't produce that nutrient on its own.

I'm not doing your homework for you. "Loss of function" is a very basic concept in genetics and you can use google I presume. I'll give you hints on the right track, but the rest is up to you. The "circles" represent the colony. The numbers are just the colony identification.

If a colony has a mutation that requires it to be supplemented by a nutrient to survive, then it follows you can work backwards from what survives on what...

Um no. That is not at all what I said: "Identifying anything other than more simplistic adaptations is difficult, regardless of the trait or species and has only been able to take off in recent years. Where there are more easily measured and clear differences, however, we often can detect selection. For instance, it is clear that there has been selection in natives of the Andes Mtns for survival at high altitude, much like in Tibet. Despite the fact that these populations have only lived in the Andes for ~10,000 years, we can detect the signatures of selection." I then give an example of selection and adaptation to a specific climate of South America, which was settled much later than North America. The only conclusion that one can derive from the proper context of my previous post is that we have been historically limited by technology and data and so we simply do not know. These are basic nutrients required by many, if not most species. Our particular need for vitamin C comes from having lost the ability to synthesize vitamin C, but which we have found in sufficient quantities from many different sources. Same with all these. None of these can be said to be of particular lack in North America as a whole. What you are trying to argue here makes no sense. Salt, water, Vitamin C, Vitamin D are no more lacking in North America than they are anywhere else.

"Biologically active form"? Thimerosal contains ethylmercury which is quickly broken down and excreted from the body. It is not equivalent to methylmercury or elemental mercury, which can persist and accumulate with known health effects. That and the amount of mercury in any vaccine was less than 1 microgram. Humans are routinely exposed to much higher levels of methylmercury through diet (fish) alone and methylmercury is not excreted like ethylmercury. Given that this nonsense has now given rise to the resurgence of diseases like measles and whooping cough, I'd say any benefit obtained from awareness of a perfectly safe additive like thimerosal is non-existent. Meanwhile, much harm and many lives have been put at risk as a result.

Its not a simple answer. You really need to know the levels of heterozygosity and genetic load of the population. Much will depend upon this. Also important is whether or not mating is truly random.

As Ophiolite has aptly pointed out, America is not so radical, but rather possessing many environments that are highly similar to that of the Old World. Humans would no more have survived in the cold of Northern Europe or Asia were it not for our cultural adaptations than they would to that of America. Identifying anything other than more simplistic adaptations is difficult, regardless of the trait or species and has only been able to take off in recent years. Where there are more easily measured and clear differences, however, we often can detect selection. For instance, it is clear that there has been selection in natives of the Andes Mtns for survival at high altitude, much like in Tibet. Despite the fact that these populations have only lived in the Andes for ~10,000 years, we can detect the signatures of selection. A clear case of adaptation to a local American environment. While this example is clearly from South America, the environment is far more radical and dissimilar to most than what North America in general is to the rest of human habitation. Your argument seems to be mired in a mindset of specialization, whereas humans are clearly a species that has evolved to be generalists in nearly all senses of the world. We are completely omnivorous and have adapted to thrive on any range of foods. It makes little sense then to speak of humans as being adapted to a particular locale like how a cave fish is adapted only to live in a cave. While we originate from a much more central location, human history is one of constant migration and admixture...hence why the genetic structure of our populations is clinal. Nor can we discount cultural adaptation, which is very much a byproduct of the evolution of our brain and behavior. It is not without reason that at least 40 some years ago people like Richard Dawkins were speaking of society and culture as extended phenotypes. If the history of invasive species and attempts at introducing species has taught us anything, it is NOT the case that an environment or place like Australia is "not adapted to species X", whatever that means. If this were the case, then we should expect the successful introduction of any non-native species. That certainly is not the case. Rather it seems that only some species are able to successfully and rapidly colonize new regions. Oftentimes these places are similar in some respect to the environment in which they evolved, thus making colonization possible. These species often exhibit traits that make them particularly successful at spreading and colonizing new locales.

Not through recombination. Through hybridization yes.

Because its the CORRECT definition. I know....crazy to insist we use correct medical definitions in discussing a medical condition in a science forum of all places....

This argument presumes that populations were evenly distributed and that the ancestors of say modern North Europeans, were the populations living in these regions 10000 years ago. Neither of these hold true. Because agriculture enabled greater population size and density, the centers of human population happened to be those agricultural regions like the Fertile Crescent and the Indus Valley. Even well up until the Renaissance, populations were far greater in Southern Europe and the Near East than regions like England. So while geographically, wheat production was originally concentrated to a small region, in terms of the number of of actual people living dependent upon it, this was no small minority, but a large fraction. Secondly, Modern people of places like Northern Europe are not the direct descendants or pure descendants of those that inhabited those regions ten thousand plus years ago. Many waves of migration, extermination, conflict, etc have led to replacement and admixture of these original populations. These waves came out of the East and South. Consider Rome's influence, after centuries of conquest. Human genetics is not such a simple thing and you underestimate the extent of man's exposure to food sources like wheat. That is nothing more than pure speculation with no facts to support it. You make spurious connections between the adoption of agriculture, the epidemiology of Celiacs and wheat allergies that have no factual basis. We have almost no clue as to the true prevalence of any gluten related health issue prior to the 1950s and this is confounded even today by self-reporting issues, awareness, and proper diagnosis. The fact that the exact same changes in skeletal remains are observed in nearly every culture that adopted agriculture, regardless of primary food source is also strong evidence against gluten being a factor. If you look at the sedentary Gulf Coast cultures where there was no wheat, rye, or other gluten containing crops and where agriculture was only a supplement to a rich marine diet; you find the exact same skeletal changes observed in every other culture that adopted agriculture. This includes also rice based cultures in China and the Indus, Maize based cultures in Mexico. It is clear from the hard evidence that this trend is entirely due to some factor other than the specific crops grown, otherwise we would see it limited to specific crops. You make such speculations despite evidence to the contrary. So yes, you are absolutely wrong about any connection between the specific crops grown and the declining health of these populations. No it does not. If wheat gluten were at all a specific cause in these factors, then we would observe declines in health SPECIFIC to cultures that produced wheat. We would not find the same correlations in rice cultures, maize cultures, and agricultural cultures dependent upon other crops and food sources. That this is a general trend to all agricultural adoption is evidence against any such effect. Thats the difference between relying on unsupported "common knowledge" and referencing actual facts and research. What you call "common knowledge" is often speculation, spurious correlation, and false. If you were to look at the actual facts as supported by research and back those by cited resources, then your conclusions would be more reliable. I already took you to task on this one. Celiacs is not an allergy and allergies can be developed and lost during a life-time, being very much influenced by environment. The two diseases operate by completely different molecular pathways, have completely different bases and are not at all equivalent. Being an autoimmune disorder and purely genetic, Celiacs is much more subject to Selection, whereas an environmentally induced allergy is far more variable and less heritable. Its basic genetics that the higher the heritability of a trait, the stronger the response to selection, that matters when we try to understand the epidemiology of a disease like Celiacs and potential reasons for its prevalence. Many, such as yourself, incorrectly think of it as an allergy and allergies are something that can be developed. But its not, so positive selection for Celiacs is indicative of factors other than the cultivation of wheat for its prevalence. As allergies can be developed and have weaker heritability, this raises a different set of questions. The situation is made worse as we do not know the true prevalence of food allergies and especially do not know their prevalence historically. The fact that when you use self-reported food allergies, that there is a significant prevalence amongst spurious factors like someone with a post-secondary education in the household, suggests that "awareness" and misdiagnosis are major contributors. But it is relevant. You have claimed that there has been an increase in food allergies, such as wheat allergies: Overtone: "The possibility that allergy to wheat gluten is actually increasing in synchrony with some other specific allergies (peanuts, bee venom) and immune system problems in general (asthma, etc) acts as counter or conflicting evidence to the implications of my observation that human beings do not have as much evolutionary familiarity with wheat gluten as is generally portrayed." In typical fashion you couch arguments in unsupported speculation. Its relevant to the fact that you have made such claims, yet the evidence is lacking. I'm not disparaging anyone. It is a valid argument that awareness and misdiagnosis likely increase the number of self-reported food allergies beyond what the true prevalence is. This is clearly illustrated in the fact that there is increased prevalence with spurious factors like post-secondary education. Overtone, we play the same game over and over again. You make speculative arguments without support from "common knowledge" (urban myths are a form of common knowledge), refuse to support them, and when pressed on the matter claim that I am insulting and don't understand the argument. Want to know how to respond? Really very simple. Rather than spouting out unsupported claims, present facts that are premised in real data. You could start by not making such a blatant mistake like claiming that Celiacs is an allergy...

I'll respond to you in full later because I need to leave in a bit, but I just have to correct you on one thing: Overtone: "Celiacs is a set of allergic reactions" ...........I pretty much stopped reading right there. Celiacs IS NOT A SET OF ALLERGIC REACTIONS. Allergies occur via IgE antibodies and inflammatory responses. Celiacs is an autoimmune disorder where the body is induced into attacking its own cells. They occur by very different pathways (Celiacs does not occur via IgE antibodies) and the molecular responses are very different. People can develop allergies and grow out of allergies. Allergies do not trigger autoimmune responses. Celiacs is genetic and you will never "grow out of it", nor will you "develop" it due to exposure. You are born with Celiacs and you die with Celiacs. In typical fashion you have not bothered to cite a single reference and it shows....Celiacs is in no way comparable to any food allergy and to suggest as much is completely wrong.

Man's intelligence and culture allows him to shape his environment and outfit him with the technological adaptations necessary to thrive in any climate. The evolution of man is one that has occurred over vast terrains, with specific adaptations evident in groups living in such extremities as the Himalayas. Quite frankly, I don't think it makes sense to speak of man being adapted to a particular climate in any way because man has evolved to shape his own environment to fit his needs. Wheat has only been the dominant crop of the Near East and Europe throughout that period, that is not a "quite small minority". Furthermore, the epidemiology of Celiacs is not so simple. Celiacs is purely a genetic disease, attributed to the frequency of certain alleles of HLA-DQA1 and DQB1. As a genetic disease, any increase in Celiacs will be driven by genetic factors and not "developed" due to exposure to wheat. The expectation is that for cultures and peoples who are most dependent upon wheat for caloric intake, that there would be selection against those alleles that cause Celiacs. That is not at all the case, with increasing evidence that there has been positive selection for some of these alleles. As these genes are involved in immune responses, particularly to bacterial pathogens, the most likely explanation is that there has been stronger selection for these alleles due to immunity and disease. This means that consumption of wheat and wheat breeding itself is not at all a factor driving the prevalence of celiacs. At most, it only reveals the hidden epidemiology of Celiacs. I wish to God that you would learn how to actually cite references. You are wrong that the adoption of wheat and rye correlates with declining aspects of human health. The decline of human health correlates in general with the adoption of agriculture, regardless of the mainstay food sources. This includes rice and maize based cultures (gluten free!!!) and other forms, such in the gulf coast, where agriculture served more as a supplement to a culture that derived most of its food from the sea. Increasingly, it looks like many of the effects of health were not directly related to nutrition, but rather lifestyle, reproduction, and population stresses. It is also not clear at all whether or not there is an actual increase in food allergies or if there is simply greater awareness resulting in both better diagnosis and/or misreporting. Most studies of the sort have relied on self-reported surveys of food allergies, which are easily subject to false positives and can be swayed by increased awareness and dare I say hypochondria. Consider one study of the prevalence of various food allergies in a Canadian population. This study relied, like most, on self-reported food allergies. For some inexplicable reason, self-reported egg and wheat allergies were much higher in households with a post-secondary graduate. You know, the sort of household that will have the sort of individual who has a greater awareness of such things, higher income, and also more likely to follow such health fads. The researchers even note that the self-reported rates are way too high based on other literature and likely to be due to confusion of various things. But you are making scientific claims and reporting supposed "facts" without providing any sources. Take the claim that you just made regarding wheat and rye contributing to declining health in ancient man. This is a scientific claim requiring supporting evidence. Its problematic that you have not provided sources, because the fact is that your claim is not true because this observation is a general trend of agriculture adoptions, regardless of food source. In making this claim and not providing the actual sources, you actually misrepresent the research.

Hexaploid wheat varieties have been cultivated by man for ~9000 years. While there is evidence that the gluten proteins that have the most profound immune responses are more concentrated in the D genome of hexaploids, they also exist in the A and B genomes of tetraploids. Man has lived with this for 9000 years. Consumption of wheat flour was far higher in the 1800s than even today. Its truly difficult to say with certainty how much incidence of Celiacs has increased since the disease was not actually identified until the 1950s. Like many such diseases, increased incidence can in no small part be attributed to better diagnosis. Prior to the 1950s, its really impossible to say how prevalent Celiacs was. There is no clear evidence that wheat gluten content has increased. I have seen this urban myth circulating the internet that GMO wheat has higher gluten content and wheat breeding is causing Celiacs. Never mind that no GMO wheat exists on the market, comparison of modern varieties to those from the 1920s (and prior to the increased incidence of Celiacs) has shown no increase in actual gluten content in modern varieties. Meanwhile, we now used purified gluten in all sorts of applications so that people may be exposed to more gluten simply as a result of consumption of purified gluten. This however has nothing to do with plant breeding or the production of wheat.

We should not see the offering of "gluten free" as evidence of a gluten problem....no more than we should see the offering of magnetic bracelets as evidence that wearing a magnet does anything other than prove a person is gullible. If someone can find a niche to make a buck, especially if it means selling it at a higher price, they will. If that means preying on the fears of people, then so be it. Wheat, by the way was domesticated in the Middle East and was the stable there and throughout Europe for thousands of years.

Correct

She would be dead if she could not consume water.

White skin appears to have evolved after humans left Africa. There are alleles that arose in different human populations after leaving Africa and there is also varying degrees of admixture with other hominids, such as Neanderthals and Denisovans, that are present in European and Asian populations and not African ones. However, the biggest difference is that Africa is the center of diversity, with more genetic diversity than in populations outside of Africa. Many, if not most, of the allele changes that occurred are the result of the bottlenecks that occurred when smaller sub-populations migrated out of Africa. Centuries of migration, invasion, etc has created a situation where there has been mixing of populations over regions. Human genetic diversity is complex and does not fit categorizations that are typical of racist ideologies. We can speak of population structure and genetic/phenotypic consequences without supporting or acknowledging racism because reality does not fit racist ideology. Quite frankly, I find talk of racism to be boring and outdated. Sure it still exists, but I think that a vast majority recognize that it is wrong both intellectually and morally and that racists as a group are to be ostracized. Those who cling to it are possess the sort of ignorance that will not be changed so I do not bother arguing with them. Actual genetic diversity and its consequences, along with reconstructing our history through genetics...tracing migrations, admixture, etc are topics I find to be of real interest.

In the short term it certainly can have an effect and I think the consequences of these short-term effects could be quite interesting. For instance, epigenetic mechanisms may enable the transition of an organism from one genetic fitness peak to another. For example, lets say you have a gene duplicate gene that over long term evolution, obtains new functionality. However, the transition to this new functionality may require a sequence of mutations that at intermeditate points reduces fitness if this gene is expressed. Silencing of the gene by DNA methylation could allow it to acquire mutations without these mutations affecting fitness as the gene is unexpressed. At some later point, should DNA methylation be lost, the mutated gene maybe re-expressing novel phenotypes. In this case, the transgenerational inheritance of the DNA methylation could allow this transition, even if intermediate steps were potentially lethal. Why I caution overemphasis of epigenetics in evolution is: 1) Its completely unknown what role it plays in evolution. 2) Epigenetics has been touted by everyone from neo-Lamarkists, Creationists, Journalists who think they know everything, and even health-fad scam artists as overturning the importance of genetics and disproving Darwinian evolution. None of this is true.

If you do not do research or contribute to the knowledge base of science, then you are not really a "scientist" in any sense of the word. There are many who have done research at various points of life, as undergrads, as grad students, etc. However, it doesn't make sense to me that having once been involved in research, if one ceases to be, that they are still as "scientist". If ever I find myself in a position where I leave doing research for a living, then I will cease to call myself a scientist. Its really that simple. Thinking logically and skeptically does not make one anymore a scientist than does growing a garden make one a "farmer" or having run a 5k makes one an "athlete".

So provide an alternative or describe what is "enough".

Science proceeds through many processes, this is true. That does not mean that it is not guided by an overarching guideline which we call the scientific method.