Evolution Is Speeding Up, Says Researcher, And We're Becoming More Different
    By News Staff | December 10th 2007 10:00 AM | 27 comments | Print | E-mail | Track Comments
    Researchers discovered genetic evidence that human evolution is speeding up – and has not halted or proceeded at a constant rate, as had been thought – indicating that humans on different continents are becoming increasingly different.

    “We used a new genomic technology to show that humans are evolving rapidly, and that the pace of change has accelerated a lot in the last 40,000 years, especially since the end of the Ice Age roughly 10,000 years ago,” says research team leader Henry Harpending, a distinguished professor of anthropology at the University of Utah.

    Harpending says there are provocative implications from the study, published Dec. 10 in the journal Proceedings of the National Academy of Sciences:

    -- “We aren’t the same as people even 1,000 or 2,000 years ago,” he says, which may explain, for example, part of the difference between Viking invaders and their peaceful Swedish descendants. “The dogma has been these are cultural fluctuations, but almost any temperament trait you look at is under strong genetic influence.”

    -- “Human races are evolving away from each other,” Harpending says. “Genes are evolving fast in Europe, Asia and Africa, but almost all of these are unique to their continent of origin. We are getting less alike, not merging into a single, mixed humanity.” He says that is happening because humans dispersed from Africa to other regions 40,000 years ago, “and there has not been much flow of genes between the regions since then.”

    “Our study denies the widely held assumption or belief that modern humans [those who widely adopted advanced tools and art] appeared 40,000 years ago, have not changed since and that we are all pretty much the same. We show that humans are changing relatively rapidly on a scale of centuries to millennia, and that these changes are different in different continental groups.”

    The increase in human population from millions to billions in the last 10,000 years accelerated the rate of evolution because “we were in new environments to which we needed to adapt,” Harpending adds. “And with a larger population, more mutations occurred.”

    Study co-author Gregory M. Cochran says: “History looks more and more like a science fiction novel in which mutants repeatedly arose and displaced normal humans – sometimes quietly, by surviving starvation and disease better, sometimes as a conquering horde. And we are those mutants.”

    Harpending conducted the study with Cochran, a New Mexico physicist, self-taught evolutionary biologist and adjunct professor of anthropology at the University of Utah; anthropologist John Hawks, a former Utah postdoctoral researcher now at the University of Wisconsin, Madison; geneticist Eric Wang of Affymetrix, Inc. in Santa Clara, Calif.; and biochemist Robert Moyzis of the University of California, Irvine.

    No Justification for Discrimination

    The new study comes from two of the same University of Utah scientists – Harpending and Cochran – who created a stir in 2005 when they published a study arguing that above-average intelligence in Ashkenazi Jews – those of northern European heritage – resulted from natural selection in medieval Europe, where they were pressured into jobs as financiers, traders, managers and tax collectors. Those who were smarter succeeded, grew wealthy and had bigger families to pass on their genes. Yet that intelligence also is linked to genetic diseases such as Tay-Sachs and Gaucher in Jews.

    That study and others dealing with genetic differences among humans – whose DNA is more than 99 percent identical – generated fears such research will undermine the principle of human equality and justify racism and discrimination. Other critics question the quality of the science and argue culture plays a bigger role than genetics.

    Harpending says genetic differences among different human populations “cannot be used to justify discrimination. Rights in the Constitution aren’t predicated on utter equality. People have rights and should have opportunities whatever their group.”

    Analyzing SNPs of Evolutionary Acceleration

    The study looked for genetic evidence of natural selection – the evolution of favorable gene mutations – during the past 80,000 years by analyzing DNA from 270 individuals in the International HapMap Project, an effort to identify variations in human genes that cause disease and can serve as targets for new medicines.

    The new study looked specifically at genetic variations called “single nucleotide polymorphisms,” or SNPs (pronounced “snips”) which are single-point mutations in chromosomes that are spreading through a significant proportion of the population.

    Imagine walking along two chromosomes – the same chromosome from two different people. Chromosomes are made of DNA, a twisting, ladder-like structure in which each rung is made of a “base pair” of amino acids, either G-C or A-T. Harpending says that about every 1,000 base pairs, there will be a difference between the two chromosomes. That is known as a SNP.

    Data examined in the study included 3.9 million SNPs from the 270 people in four populations: Han Chinese, Japanese, Africa’s Yoruba tribe and northern Europeans, represented largely by data from Utah Mormons, says Harpending.

    Over time, chromosomes randomly break and recombine to create new versions or variants of the chromosome. “If a favorable mutation appears, then the number of copies of that chromosome will increase rapidly” in the population because people with the mutation are more likely to survive and reproduce, Harpending says.

    “And if it increases rapidly, it becomes common in the population in a short time,” he adds.

    The researchers took advantage of that to determine if genes on chromosomes had evolved recently. Humans have 23 pairs of chromosomes, with each parent providing one copy of each of the 23. If the same chromosome from numerous people has a segment with an identical pattern of SNPs, that indicates that segment of the chromosome has not broken up and recombined recently.

    That means a gene on that segment of chromosome must have evolved recently and fast; if it had evolved long ago, the chromosome would have broken and recombined.

    Harpending and colleagues used a computer to scan the data for chromosome segments that had identical SNP patterns and thus had not broken and recombined, meaning they evolved recently. They also calculated how recently the genes evolved.

    A key finding: 7 percent of human genes are undergoing rapid, recent evolution.

    The researchers built a case that human evolution has accelerated by comparing genetic data with what the data should look like if human evolution had been constant:
    • The study found much more genetic diversity in the SNPs than would be expected if human evolution had remained constant.
    • If the rate at which new genes evolve in Africans was extrapolated back to 6 million years ago when humans and chimpanzees diverged, the genetic difference between modern chimps and humans would be 160 times greater than it really is. So the evolution rate of Africans represents a recent speedup in evolution.
    • If evolution had been fast and constant for a long time, there should be many recently evolved genes that have spread to everyone. Yet, the study revealed many genes still becoming more frequent in the population, indicating a recent evolutionary speedup.

    Next, the researchers examined the history of human population size on each continent. They found that mutation patterns seen in the genome data were consistent with the hypothesis that evolution is faster in larger populations.

    Evolutionary Change and Human History: Got Milk?

    “Rapid population growth has been coupled with vast changes in cultures and ecology, creating new opportunities for adaptation,” the study says. “The past 10,000 years have seen rapid skeletal and dental evolution in human populations, as well as the appearance of many new genetic responses to diet and disease.”

    The researchers note that human migrations into new Eurasian environments created selective pressures favoring less skin pigmentation (so more sunlight could be absorbed by skin to make vitamin D), adaptation to cold weather and dietary changes.

    Because human population grew from several million at the end of the Ice Age to 6 billion now, more favored new genes have emerged and evolution has speeded up, both globally and among continental groups of people, Harpending says.

    "We have to understand genetic change in order to understand history,” he adds.

    For example, in China and most of Africa, few people can digest fresh milk into adulthood. Yet in Sweden and Denmark, the gene that makes the milk-digesting enzyme lactase remains active, so “almost everyone can drink fresh milk,” explaining why dairying is more common in Europe than in the Mediterranean and Africa, Harpending says.

    He now is studying if the mutation that allowed lactose tolerance spurred some of history’s great population expansions, including when speakers of Indo-European languages settled all the way from northwest India and central Asia through Persia and across Europe 4,000 to 5,000 years ago. He suspects milk drinking gave lactose-tolerant Indo-European speakers more energy, allowing them to conquer a large area.

    But Harpending believes the speedup in human evolution “is a temporary state of affairs because of our new environments since the dispersal of modern humans 40,000 years ago and especially since the invention of agriculture 12,000 years ago. That changed our diet and changed our social systems. If you suddenly take hunter-gatherers and give them a diet of corn, they frequently get diabetes. We’re still adapting to that. Several new genes we see spreading through the population are involved with helping us prosper with high-carbohydrate diet.”


    Given the mutations, I fail to see how natural selection could be acting as a "guide" on evolution in the modern western "civilization" as we almost all have children before dying, regardless of our "adaptation" to our environment...

    There's surely a simple explanation I'm missing. Do you have one?
    Gerhard Adam
    Natural selection isn't a "guide", it is a filter.  So if the environment changes sufficiently to where a particular adaptation makes individuals "better" at surviving than others, then those changes will tend to make it into future generations.

    Obviously "better" is a value judgment and is only a subjective expression of what actually occurs, since it simply means that an individual (or the population) ultimately shifts in a direction that is better able to handle the environment they are in.

    It is wrong to think that natural selection operates on each generation, because it is quite possible (and quite normal) for traits (or subtle changes) to be passed to future generations, but not have any environmental factors that make those traits important enough to affect survival.  In which case, those traits will become randomly distributed through a population and will only be noticeable if a sudden change in circumstances occurs to where that trait becomes important.  It might never be important, in which case it will not be "selected" for.

    In the case of humans, our adaptability is increasingly influenced by our culture and other factors well beyond simple survival (in the hunter/gatherer sense).  So depending on the society we live in our survival is measured by different criteria of "success".  However, it is also important to remember that survival isn't the criteria for evolution.  An individual must survive, successfully reproduce, and then ensure that offspring survive to reproduce (presumably transferring what they've learned, etc.) to achieve success in future generations.  As an example, you can observe such changes by considering how humans are expected to be literate (read and write) despite the fact that only a few hundred years ago, such a skill was considered elite.  Even today, most people have heard of Einstein's Theory of Relativity and many people have varying degrees of understanding it, despite the fact that less than a century ago, it was a radical theory only understood by a handful of people.  It is even easier to see when you consider how each generation becomes more comfortable with novel technologies and exploitation.  Each of these changes are "selective" in some sense and will shape the future of our social group (society).

    So when you examine humans, it is more appropriate to examine the society or culture, as a whole, to gain more insight into the selection criteria and evolution of the species.   In that way it becomes a bit easier to see the influences that occur generation to generation that will ultimately determine the direction and shape that future societies take.  It's like examining the evolution of ants.  You don't examine an individual ant (since they can't even reproduce any more), but rather you examine the behavior and activity of the entire colony to determine how natural selection is operating.  It's the same for humans.  Despite their favorite mythology, humans can only survive in groups and there is no such thing as an "individual" that has any biological survival potential.
    Mundus vult decipi
    Thanks for your answer! It's a bit clearer now...
    Gerhard Adam
    It's interesting to consider the case of the Peppered Moth, which is often used to show natural selection at work.  This is the story of moths that turned black in color because of the pollution so that this helped camouflage then from predators.

    If you look at the attached link you'll see that the colors shifted to black and now have shifted back to white.  What this illustrates is that a particular trait may lie dormant until an environmental trigger makes it relevant.  So, if pollution is a primary environmental factor, then black moths tend to survive to adulthood and reproduce.  Similarly, when the reverse occurs.

    However, what's important to note is that neither type of moth ever completely loses the genes for both traits.  As a result, there is an ability to "adapt" back and forth as the environment changes.  If a particular condition existed for long enough periods, then it is possible for the trait (the genes that code for it) to become fixed in the population in which case there would be no "going back".  At this point it would require a new mutation to get back to the opposite state.  Biology doesn't have an "undo" function to roll back to a previous state, it can only move "forward". 

    Having said that, it is also important to recognize that natural selection and evolution do not have a direction and do not inevitably result in increased complexity.  These are often both claims that are erroneously attributed to evolution.   Genes do not possess a memory of past traits, so they can only change from the current moment on (which is what gives rise to the illusion that it is a forward direction). 
    Mundus vult decipi
    Thank you Gerhard. That clear explanation helps a lot.

    I wonder how many generations it takes for a species to adapt to changing environments? I suppose it matters how extreme the changes are and if the species already has the genetic code required for the adaptation.

    Gerhard Adam
    Well, you can easily imagine that for a species like bacteria, it could be in a single generation.  Imagine if 1% of a population carries the genes for specific antibiotic resistance.  When it encounters the antibiotic, then 99% percent of the population dies off.  If the heritability of the resistance is 100%, then you'd have a resistant strain in one generation.  (NOTE: The problem in bacteria is complicated by the fact that bacteria can voluntarily exchange genetic information with each other through conjugation, so it isn't solely dependent on chance).

    If the environmental change is too extreme, there likely won't be time to adapt, so some useful traits must already be present.  One thing that is often overlooked is that genes aren't as specific as people think but rather may govern a range of traits.  For example, the genes that would allow you to run fast, would never be fully expressed unless you actually had the need to run fast.  If you were just a couch potato, then you'd never even know you possessed the gene.  Now, if the environment suddenly required you to be able to run fast, then you'd already have an advantage.  However, even this would require that you develop those muscles and train to maximize your genetic potential.  Failure to do that would also result in the gene being irrelevant.  Of course, none of this protects you from the random problem of simply falling into a hole or getting hit on the head.

    One thing that is quite interesting is the role of epigenetics in influencing gene expression.  It appears that there can be influences from the mother that determine whether the genes in the child actually express and even the degrees of that expression.  As a result, there's a chance that the environmental influences the mother is experiencing can in some limited fashion actually influence how the offspring develops.  In other words, a mother's diet can influence what genes may actually be expressed in her offspring.  Here's a link that discusses some of that with "yellow mice".  There's also more discussion that deals with other inheritance systems that can influence the genome.

    Ultimately the point in all of this is that selection can only "filter" out animals that actually exist.  Genes obviously do not know what problems an organism may face, but it appears that epigenetics may allow a bit of "tweaking" to influence outcomes based on the environmental circumstances.  In addition, there is learning and culture which will also influence the ability for animals to survive, which in turn will affect the genome that is conducive to those methods. 

    It is also useful to consider that many genes are conserved over the long-term and continuously reused in many (or all) species.  Often they are quite generic, dealing with body structure (such as front/back top/bottom, etc.)  As a result, a gene doesn't have to code uniquely for each animal, but codes "appropriately" for each animal.  This makes the water a bit muddier when it comes to considering how adaptation works.  The main point is to avoid considering evolution as having a direction.  You cannot filter what doesn't exist, and there is no feedback mechanism to notify the organism of future problems (beyond what I alluded to regarding epigenetics).
    Mundus vult decipi
    Do you think if the climate continues to change on Earth (get hotter or colder) humans will keep evolving and adapting to our environment? Do you think our planet could ever get to extreme in temperature that it will kill us? Just had a thought while reading your posts and all the posts on here...thanks for your insight..have a great day!

    Gerhard Adam
    I don't believe temperature itself is a problem, since humans readily inhabit extremely cold as well as extremely hot regions.  The problem is everything else that depends on temperature.  Consider how many insects we deal with and their life cycles, then imagine what happens if it gets hotter (i.e. they can migrate further north), or it gets colder.  Imagine the same thing for disease vectors, weather patterns based on where we grow crops,  the pests that our crops have to contend with, and the diseases that can affect livestock.  For example, if we suddenly find the southern U.S. to be subject to malaria, then we'll have to deal with it, just like Africa deals with it.  It isn't likely that there will be any selective force that changes our evolution in any appreciable sense.  Certainly our technology will make a huge difference, but it isn't likely that there would be much of a biological response. 

    These are the real issues regarding climate change.  So, from a human perspective we can and will accommodate whatever happens, because we have a huge technological lead in being able to deal with a variety of problems and conditions.  However, I'm not sure if the same can be said for our social institutions regarding economics, politics, etc.  If you consider that the majority of our "natural disasters" occur because we pretty much expect nature to go around us, and consequently we suffer because of our social structure which demands that we pick a spot and stay on it.  I don't believe it's a coincidence that our primitive ancestors were nomadic, however, I'm equally certain we won't be going back to such a lifestyle any time soon either.

    So, whatever happens to the climate, it will be how we respond socially, economically, and politically that will be the true test of our adaptability.  In my view, the biology is fine (no overt selection pressures).
    Mundus vult decipi
    Some quotes from your last link:

    "Unlike most genetic variations, commonly epigenetic variations are induced, are repeatable, are reversible, and often occur at a higher rate than gene mutations. These properties make their effects on evolution very different from those of genetic variations: Evolutionary change can be more rapid and have more directionality than gene based models predict.

    Mothers have additional routes of information transfer through materials in the egg and, in mammals, through the womb and milk. Both parents can also transfer information through faeces, saliva, and smells.

    Daughter cells get “free” information from their parents and do not have to spend time and energy finding appropriate responses themselves.

    It is clearly not possible to reduce heredity and evolution to genes, not just because the interrelationships are very complicated (which they are), but because of the partial autonomy of different systems of inheritance."

    That last sentence was all it took to blast my decades old model right out of the water.

    :sigh. So much to learn. So little time.

    Gerhard Adam
    A very good book that deals with these issues is:

    Evolution in Four Dimensions by Eva Jablonka and Marion J. Lamb

    Specifically it discusses Genetic, Epigenetic, Behavioral, and Symbolic influences on evolution and natural selection.
    That last sentence was all it took to blast my decades old model right out of the water.
    I understand.   However, I suspect it gets even more complicated than that.  Consider that if you had the perfect technology and the perfect means to produce a perfect clone, such that there were absolutely no defects in the process.  Let's further assume that you could do this in a completely sterile environment, so that when you were done you have a 100% perfect genetic replica of the original.  The interesting point is that it would be non-viable and ultimately die.

    The point being that in a human (as an example), we have 10 times the number of microbes living in and on us, as we have cells (about 100 trillion microbes).  Many of them we absolutely depend on for our survival, and yet they aren't related to our genetic information at all.  Therefore, we have to pick them up from our environment into order to develop the proper levels of microbes in our systems.  Contemplate that, the next time you ponder the problems of a Star Trek transporter.

    Obviously there is some degree of controversy regarding how much influence any of these systems have overall regarding the genome, but (in my view) most of that is simply resistance to the notion that the gene isn't the definitive unit of selection.  Basically, life is still more nuanced than some of the simple mechanistic perspectives once thought (which is why computer analogies are horrible).  :)
    Mundus vult decipi
    Amazon $12.47, Woot!

    Well, thanks to you, E4D is on my 'must read' list now.

    Yeah, I gave on my transporter long ago. Anything so complex as a lead pencil would require so many resources that it wouldn't be worth the energy expended.

    I forgot to mention how funny it was when my tortured brain conjured up the image of a yellow mouse running with a couch potato. :)

    Gerhard Adam
    That would be a funny image ;)
    Mundus vult decipi
    I have some questions that I would like to ask, Gerhard. This is a series on evolution, but this may not be the best place to discuss the questions. I’ll leave it to you to decide whether to discuss here or if you’d like to start a new article. Or two. Or three.

    1. What would you consider to be the prime mover in the relatively rapid selection for a larger and more complex brain in humans?
    2. Can you think of an event that might trigger the de-selection of, say, 90% of the human species?
    a. Disregarding near instantaneous events such as a meteor impact.
    b. And, disregarding extremely long time frames such as the next ice age.
    c. So, say in a 5-50 year frame.
    d. My first guess would be a pandemic. However I doubt the result would be so high. Perhaps more in the .50-.75 range due to the fairly large pockets of remote habitats.
    e. Second guess is nuclear warfare, but with a lower number for the same reason as in d.
    f. I don’t believe that global warming has the potential for a .90 elimination rate either.

    Gerhard Adam
    Unless someone were to strenuously object, its as good a place to discuss it as any (especially since the author can't complain that the thread has been hijacked).
    1. What would you consider to be the prime mover in the relatively rapid selection for a larger and more complex brain in humans?
    Wow, that's a tough question and I'm not sure I have a good answer.  Before getting into this, perhaps you could explain why you think humans need a larger, more complex brain?  Basically what are you envisioning would be taking place?  Greater intelligence?  If so, what do you mean by that?  Specifically how would we define intelligence and what would it mean to have more of it?
    The corollary to that question is to consider what evidence we have that we have some deficiency that would be addressed.  Note that we're talking about a physical limit here, and not simply how some people simply choose to abuse their brains.  The transhumanist movement keeps talking about a human/machine connection, but they can't seem to pin it down to anything more substantive than arbitrarily having more "storage".  They certainly talk about being able to download a new skill into your brain, but how does that translate into actually "knowing" that skill.  For example, what does it mean to "know" how to play a guitar?  Is it simply a matter of manual dexterity?  Knowing the notes?  Knowing the fret patterns?  If so, then why is every musician capable of mastery those skills and yet remain unique enough to where their performances are recognizable?

    In a nutshell, I want to take the question seriously so that it doesn't become a series of idle speculative claims.
    2. Can you think of an event that might trigger the de-selection of, say, 90% of the human species?
    Yeah, December 2012 :)

    Actually I think that such an event would occur with multiple factors.  Nuclear war or a pandemic wouldn't likely produce that result by themselves, but we have to consider secondary effects and consequences.  For example, how readily could we dispose of the dead?  Would they become a source of disease and contamination?  What would we lose if our infrastructure collapsed because we lacked the people to run it?  Consider food production, energy needs, etc.  Also, the more people we lost, the more critical skills may be lost, so we would find millions of people essentially trapped in cities with no place to go (regarding their survival needs).  Simple things like finding sufficient sources of clean water, preserving food, etc. are all problems that would rapidly become crisis. 

    People like to talk about how adaptable humans are, but it is important to remember that this planet is incapable of supporting 7 billion humans.  That is achieved only through our technology, which in turn is driven by our unique social organization that gives rise to a level of cooperation and integration well beyond anything ever seen in tribal societies.  Therefore if something caused that infrastructure to collapse, it could very well indicate the end of the majority of humans, even though the initial event didn't kill them.  In addition, if such a collapse occurred, the greatest immediate threat would be from the ensuing anarchy.

    Mundus vult decipi
    Heh. I'm good at the hijacking part of it.

    I didn't frame my first question very well at all. I'm not looking forward. Instead, I’m looking at the seemingly rapid rate of change that did occur. And, quizzing myself about the possible reasons for the increase in size and complexity. The development of language certainly has to be in consideration, but there may be more that had a greater impact on the rate of change.

    In question two, I did kinda-sorta factor in the collateral damages in my guesses. I’m thinking that what we call the industrialized nations would be decimated by either pandemic or nuke war. A festering pile of uselessness.

    So, if we have ~7 billions of folks, and lose 90%, that still leaves ~630 millions spread out in the Central and South Americas, Central Africa, outer portions of India and China with some unknown number in the hinterlands of Russia, and probably more in the island nations.

    That is certainly enough of a gene pool to keep the species alive. Providing that things don’t go farther downhill faster. Hmmm. Like a movie plot without the pretty girls.

    Gerhard Adam
    ...that still leaves ~630 millions spread out...

    That is certainly enough of a gene pool to keep the species alive.
    Definitely, especially when you consider that the human species was probably down to around 2000 breeding pairs before they migrated out of Africa.  Essentially they were on the verge of extinction.
    The development of language certainly has to be in consideration, but there may be more that had a greater impact on the rate of change.
    I think most people agree that language was certainly a big factor.  However, that also raises the question of why language?  My own purely speculative sense of this, is that language was actually a secondary or co-developed capability in the brain.  Just like most animals, we possessed intelligence and problem solving capabilities, but that wouldn't be enough to differentiate us in the direction we ultimately went.  My thought is that besides problem solving, we developed the ability to solve problems "abstractly".  In other words, instead of having to see the problem, we could begin to imagine problems, which lead us to "what if" kinds of questioning.

    As a result, (in my view) humans became the first species that could completely operate from their imagination.  Consequently this would've created the requirement for language.  After all, if you don't actually have the "abstract" entities in front of you, there's no way to share what's in our brains except through language.  If it simply involved pointing to trees or animals, there would've been no requirements. 

    So, my perspective is that as our brains allowed for increasing levels of abstraction, we needed language to be able to convey these thoughts to others and share our views.  From this, it would've lead directly to the formation of early cultures.  Possibly even creating selection pressures for those groups that were able to share their thoughts better than others, as well as those that had more workable "belief systems" that they've abstracted.

    Anyway ... just a thought
    Mundus vult decipi
    I like it.

    This part: "Possibly even creating selection pressures for those groups that were able to share their thoughts better than others, as well as those that had more workable "belief systems" that they've abstracted.", could very well be the catalyst: intraspecies competition spurring the steeds of the four horsemen.

    Thanks for your time.

    Here is something which is relevant to the United States of America and race relations that I have never seen brought up.  The possibility that African Americans who's ancestors were slaves, were selectively bread.  
    Slave owners were consummate agriculturalist.   From John Rolfe and Pocahontas who cross bread to strains of Tobacco to make what we know today.... to Thomas Jefferson.  They knew how to breed plants and animals to have traits etc which benefited them.  

    I really wonder if, on some limited basis, African Americans were selectively bread to have certain traits.   Traits that would make a good field hand who would not question authority.... 

    I just did some quick googleing and found this.

    The historian E. Franklin Frazier, in his book The Negro Family, stated that "there were masters who, without any regard for the preferences of their slaves, mated their human chattel as they did their stock." Ex-slave Maggie Stenhouse remarked, "Durin' slavery there were stockmen. They was weighed and tested. A man would rent the stockman and put him in a room with some young women he wanted to raise children from."

    Now that is something I would like to see an anthropologist check out.  The implications of this could be massive.  If true this is the real reason that reparations for slavery ought to be paid out... a crime against the African American genome was committed which we suffer the consequences of to this day. 

    Of course I cannot be too preachy given what I have found out about my own family and it's role as free people of color from abt 1630 onward.
    Science advances as much by mistakes as by plans.
    Gerhard Adam
    Traits that would make a good field hand who would not question authority.... 

    The implications of this could be massive.  If true this is the real reason that reparations for slavery ought to be paid out... a crime against the African American genome was committed which we suffer the consequences of to this day.

    Well, I think that would be a real stretch.  After all, we don't really have a good handle on that in animal husbandry when trying to select for specific behavioral traits (i.e. disposition, obedience, etc.).  I would question any slaveowner's ability to recognize that someone was "genetically" compliant versus simply responding to their circumstances.  After all, without an actual genetic component to the behavior that is heritable, it's meaningless. 

    I think the evidence is pretty conclusive that human behavior is not subject to such a high degree of genetic control.  After all, besides our genes, we are influenced by our behavioral systems (i.e. watching and learning from others), as well as our cultural systems which will all influence what kind of people we are.  Genetics is simply insufficient to the task.

    BTW, I'm not questioning whether slaveowner's engaged in such forced matings, and potentially that it might even have been their intention to do exactly as you said.  My point, is that it simply isn't feasible, especially over the short-term during which it occurred.  If you were to accelerate something like that you'd have to try and amplify the traits through a great deal of inbreeding.  That would cause too many secondary problems to be viable.
    Mundus vult decipi
    I see your points.  However I find it hard to believe that they would not have tried.  
    Science advances as much by mistakes as by plans.
    Gerhard Adam
    They may well have tried, but my point is that they couldn't succeed.  So, regardless of the attempt, it would be hard to argue that anyone alive today is a product of selective breeding in any material sense.

    Bear in mind that the owners already had control of the slaves, so if they were going to selectively breed, I'd be inclined to think it was for strength or stamina.  Compliance was all but assured in most cases, although many might try to escape, they weren't likely to revolt.
    Mundus vult decipi
    Here is something which is relevant to the United States of America and race relations that I have never seen brought up. The possibility that African Americans who's ancestors were slaves, were selectively bread.
    Discussions on race are taboo.    In 1988, CBS sports analyst Jimmy The Greek said that and was fired for it.   So it isn't that it's never been brought up, it's that white people don't like being fired for discussing the history of black people, even if it's exactly what black people say.
    I vaguely remember hearing about that.  I was 8 at the time. 

    I know what you mean.... that's the very reason I defended Kanazawa.  He pointed out something that Henry Louis Gates pointed out in a documentary he did for PBS (Noting how in Brazil very few of the "beautiful people" on the covers of the magazines are black or even brown for that matter.)

    The fear is that someone will use such a history to justify negative discrimination in the here and now.  That lazy inner city teachers will say "see they aren't able to learn" etc...  I think and any thinking black person knows that such research would lead to positives.  It would add context to the impact that slavery had on the AA community, that 80 years of indentured servitude (1619-1700),  160 years of slavery, and 100 years of jim crow.... won't go away over night.  It would make it something non black people could relate to.

    Science advances as much by mistakes as by plans.
    I've never heard of anything like that Hontas. It wouldn't surprise me a bit if it were true though.

    Hello Gerhard Adam,

    I very much enjoyed your patient explanations regarding evolution and genetics to the people on this thread. Please tell me about your educational background, and what you do for a living. Oh, and what's the story behind the cowboy hat? : )

    Thank you,


    Gerhard Adam
    Education in physics and biology.

    The cowboy hat is what I wear when I need to take care of the animals (horses, these days).  I used to have cows, goats, and burros too.  It's good for keeping the sun off and specifically it's good for keeping the rain off your head in the winter.
    Mundus vult decipi