Human evolution Intelligent Design

Lactose tolerance: Human ancestors evolved “far more quickly than was originally thought”

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dog-powered milk cart from Holland long ago

From George Busby, offering five examples, at the Conversation:

3. Our ancestors evolved surprisingly quickly

Interbreeding accounts only for a tiny amount of human adaptation around the world. Analyses of DNA are showing us that, as our ancestors moved around the world, they evolved to different environments and diets far more quickly than was originally thought.

For example, the textbook example of a human adaptation is the evolution of lactose tolerance. The ability to digest milk past the age of three is not universal – and was previously assumed to have spread into Europe with agriculture from the Middle East starting some 10,000 years ago.

But when we look at the DNA of people over the past 10,000 years, this adaptation – which is now commonplace in northern Europe – was not present until around around 4,000 years ago, and even then it was still quite rare. This means that the spread of lactose tolerance across Europe must have occurred incredibly quickly. More.

But why is lactose tolerance the sort of thing that was originally thought to be difficult to develop? The big story is the sudden appearance of complex traits, not simple ones.

See also: Making human brain evolution look gradual by ignoring enough data… We are used to governments’ disappearing monster deficits (and, to be honest, in some cases, disappearing people) this way. It feels squishier when scientists do it. Unless, of course, evolutionary biology isn’t really a science anymore. More a form of Darwinian storytelling where the preferred narrative is chosen…

13 Replies to “Lactose tolerance: Human ancestors evolved “far more quickly than was originally thought”

  1. 1
    Nonlin.org says:

    But is lactose tolerance genetic? And if so, how come American born children of Chinese immigrants eat cheese pizza when their parents are presumably lactose intolerant?
    Sorry, this is just anecdotal as I couldn’t find relevant statistics on this matter.

  2. 2
    cornu says:

    The trait discussed here is better thought of as lactase persistence, and that certainly has a genetic basis. The Wikipedia article is a good summary https://en.m.wikipedia.org/wiki/Lactase_persistence

  3. 3
    gpuccio says:

    Nonlin.org:

    Many years ago, I was part of the test population, together with many others in the hospital where I worked, in a research about lactose tolerance in adults in different populations conducted by a german researcher.

    We were given an oral load of lactose, and after some time we had to breathe into a balloon-like bag, so that our expired air could be tested for some component derived from non absorbed lactose metabolism.

    Well, the result was that I, like most other participants, were lactose non absorbers. That is the common conditiion in our population (Southern Italy).

    The point is: I have always loved milk, and I take it regularly in my daily life. I have never had major problems from that. However, if I take great quantities of milk, I can see the consequences!

    So, yes, the persistance of full lactase activity in adults is definitely genetic, and it can be found mainly in Northern Europe..

  4. 4
    LocalMinimum says:

    My understanding is that it’s simply the breaking of a switch that turns off lactose processing enzymes (lactase) around the age of weaning. So devolution, again.

  5. 5
    Nonlin.org says:

    I see no good understanding of this adaptation.

    More importantly, lactose tolerance is a metabolic adaptation like many others including color changes, antibiotic, antibiotic-resistance, etc. This is what organisms do day in and day out. Yet none of these normal adaptations has ever been observed to cause transmutation into other organisms (aka evolution) – the primary claim of Darwinism.

  6. 6
    gpuccio says:

    It seems it is simply a case of SNPs in an enhancer region. Nothing else. Possibly naturally selected by nutrition habits.

    But only possibly.

    A minimal example of microevolution, if true.

  7. 7
    critical rationalist says:

    First “We’re surprised about X” doesn’t mean X doesn’t mean X is incompatible with evolutionary theory.

    Second, why do you think we’d get evolutionary theory exactly right in the first place? How would that work, in practice?

  8. 8
    cornu says:

    Non Lin, you might want to search Google scholar. It’s a very well understood adaptation, multiple different SNPs in different populations and their prevelance is certainly the result of selection.

  9. 9
    Nonlin.org says:

    cornu@8
    gpuccio@6

    I did and didn’t find something clear. Provide the link if you think otherwise.

    What “selection”?

  10. 10
    gpuccio says:

    Nonlin.org:

    The natural selection of the described SNPs is, of course, an inference. It is derived from arguments of population genetics. It is notg absolutely certain, and many things are not clear, but there is certainly some evoidence in its favour.

    You can look for “lactose persistence selection” in Pubmed. Here are some of the most recent papers:

    Human adaptation and population differentiation in the light of ancient genomes

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4802047/

    Positive selection of lactase persistence among people of Southern Arabia

    http://onlinelibrary.wiley.com.....2/abstract

    On the Evolution of Lactase Persistence in Humans

    https://www.annualreviews.org/doi/abs/10.1146/annurev-genom-091416-035340?rfr_dat=cr_pub%3Dpubmed&url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&journalCode=genom

    I would like to understand why you seem to have problems with the possibility of natural selection of a simple trait for some adaptational advantage. Maybe it is true or not true for lactose persistence, but it is a process that certainly happens. We can observe it in simple cases of antibiotic resistance.

    It is the only form of natural selection that has ever been observed, and it is no support at all for the neo-darwinian theory. Indeed, it is a very strong argument against it:

    1) RV + NS can cause the fixation of extremely simple traits (those that are in the probabilistic range of RV). That can be observed, or correctly inferred.

    2) RV + NS cannot generate any form of complex functional trait (because they are not in the range of RV, and there is no gradual selectable pathway to them). Therefore, that kind of process has never been observed, or correctly inferred.

  11. 11
    Nonlin.org says:

    gpuccio,

    Quote from your link:
    “…the story of lactase persistence is far from clear: Why are lactase persistence frequencies low in Central Asian herders but high in some African hunter-gatherers? Why was lactase persistence strongly selected for even though milk processing can reduce the amount of lactose? Are there other factors, outside of an advantage of caloric intake, that contributed to the selective pressure for lactase persistence?”

    Sure, it makes sense as an adaptation, but it just doesn’t seem “very well understood”. That’s all.

    Yes, I do question the concept of natural selection: http://nonlin.org/natural-selection/

  12. 12
    gpuccio says:

    Nonlin.org:

    “Yes, I do question the concept of natural selection”

    Well, I have made more or less the same arguments against the powers of NS, and have tried to distinguish it from Intelligent Selection. See here:

    https://uncommondescent.com/intelligent-design/natural-selection-vs-artificial-selection/

    and here:

    https://uncommondescent.com/intelligent-design/what-are-the-limits-of-natural-selection-an-interesting-open-discussion-with-gordon-davisson/

    I would say that we agree on most things!

    But I would never say that I question the concept of natural selection. Because NS exists.

    I definitely question the powers of NS: they are extremely limited.

    As I have tried to argue in my OPs quoted above, NS can only rely on RV, and the powers of RV are extremely limited, as I have argued here:

    https://uncommondescent.com/intelligent-design/what-are-the-limits-of-random-variation-a-simple-evaluation-of-the-probabilistic-resources-of-our-biological-world/

    You say the same thing:

    “Selection is limited to a narrow set of possible adaptations – what is not there, cannot be selected.”

    That’s true. But I don’t agree that:

    “Natural Selection is Intelligent Selection which is always done by an Intelligent Selector”

    NS and is are well distinct. You are right that neo-darwinists always try to pass cases of IS as NS: the example of breeders is perfectly correct.

    But antibiotic resistance (in its simple form) is an example of NS. It relies only on random events and on some “advantage” which, in certain conditions, is linked to those simple random events.

    Now, I agree with you (and with Behe, of course) that simple antibiotic resistance in really a “loss of functional information”. As you say:

    “Antibiotic resistant bacteria still cannot survive extreme temperatures and chemical concentrations and their resistance decreases when the stimulus is removed.”

    OK, but the simple fact remains that in some conditions (an environment where antibiotics are definitely more important than extreme temeratures as a selecting factor, for example) those bacterial strains are favored.

    And we have clear cases where NS favors some traits in humans, even if they are deleterious and potentially harmful.

    For example, it is well known that sickle cell disease (which is due to one single SNP) in its heterozygote form (sickle cell trait) confers some good resistance to malaria.

    The mechanism for that is well known, and the NS of the conndition is confirmed by the geographical distribution of the disease:

    Sickle Hemoglobin Confers Tolerance to Plasmodium Infection

    http://www.cell.com/cell/fullt.....11)00384-9

    Heterozygote advantage

    https://en.wikipedia.org/wiki/Heterozygote_advantage

    Now, there can be no doubt that sickle cell disease is a disease, and it has a lot of negative consequences, even in its heterozygote form. But the point is: the heterozygote disease is not extremely severe, and is compatible with survival.

    Even so, the heterozygotes would be much rarer, if NS did not “protect” them in the regions where malaria if endemic.

    The mechanism is the same as for simple antibiotic resistance: a simple random variation causes a loss of function, but that loss of function, by mere chance, gives some advantage in some context. Here, malaria has the same role as antibiotics.

    I am insisting in these details for a simple reason: I find your site and your arguments extremely good and precise. What I am trying to say is that there is no reason to deny the simple forms of NS which do exist, because they have no bearing to the general ideas of complex functional information and of intelligent design.

    Acknowledging the true forms of NS allows us to fully understand the extreme limits of that process, and to distinguish it correctly from Intelligent Selection, which is often used as fake NS in neo-darwinist propaganda.

    See for example my old critical analysis of the “famous” Szostak paper, for example here:

    https://uncommondescent.com/intelligent-design/what-are-the-limits-of-natural-selection-an-interesting-open-discussion-with-gordon-davisson/

    at #62, where I compare the Szostak paper (which uses Intelligent selection to simulate NS) to another paper which correctly uses NS to study its powers and finds its limits (the Rugged landscape paper).

    The simple truth is that NS can only rely on one function (survival), whichis however the result of already existing functional information, and on random variations of that existing information, whose “creativity” is drastically limited to simple events (usually one, two AAs variations at most).

    All complex solutions are completely out of range for those mechanisms.

  13. 13
    Nonlin.org says:

    gpuccio,

    But antibiotic resistance (in its simple form) is an example of NS.

    I call that IS or better yet adaptation:
    “Predators, plants, birds, insects or bacteria, all show intelligence and the willful pursuit of predetermined goals. When interacting with the inert environment, organisms self-select rather than being selected by this environment. As soon as the organism dies and becomes part of the lifeless universe, all selection of that entity ceases. Rocks do not select each other, do not self select and are not selected by the environment.”

    Yes, there is intelligence in the lowly bacteria as far as I can tell. And they select themselves by going wherever possible and not expanding where not.

    As shown, NS fails the most basic definition since survival is not directly tied to phenotype. Why then insist on using the concept of NS? There is no reason to borrow the Darwinistas language. No microevolution, no NS, no “fitness”, “phenotype”, “speciation”, etc. How can the Darwinistas take you seriously when you accept and operate in their mind frame and only seek fault at the edges when their whole mind frame is rotten?

    Work in progress challenging Everything that doesn’t make sense…
    The evolution narrative fails:
    – 1. “Natura non facit saltum” (gradualism) is illogical and contrary to everything we know about the absolute discreteness of organisms – http://nonlin.org/gradualism/
    – 2. “Randomness” is unknowable and never a source of creativity – http://nonlin.org/random-abuse/
    – 3. “Blind, Unguided and Purposeless Process” – the qualifiers are utterly unsupported by evidence and incompatible with any Process defined as a set of Steps Taken towards an End
    – 4. “Natural Selection” fails as everything is natural, all selections are done by Intelligent Selectors and are limited to variations around a mean rather than “divergence of character”. Natural Selection also lacks creativity, so cannot explain the variety of organism designs – http://nonlin.org/natural-selection/
    – 5. Phenotype is an unstable infinite set, hence unknowable, theoretical and irrelevant
    – 6. Selection is Survival and “Fitness” is a redundant concept since the only measure of “Selection” and “Fitness” is the Survival of descendants
    – 7. “Benefit” and “optimization” are anthropic concepts incompatible with the mechanistic universe envisioned by Darwin and his followers
    – 8. LUCA (Last Universal Common Ancestor) from Abiogenesis is illogical since, in a generic “primordial soup” scenario, if one happens then many happen contrary to no evidence of “spontaneous generation” in nature or laboratory – http://nonlin.org/warmpond/
    – 9. There are no examples whatsoever of “Arising” as in “Arising of Everything” and “Life vs. Entropy” – http://nonlin.org/arising-of-everything/, http://nonlin.org/life-and-entropy/
    – 10. One must presume evolution to see evolutionary links in the fossil record – this “proof” is circular logic. Conversely, organisms’ resemblance is typical for common designed entities.
    – 11. “Species” is a failed concept as the separation between species is arbitrary, therefore, no “speciation” and no “origin of species” – http://nonlin.org/missing-evidence/

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