Adam and Eve still a possibility?

Geneticist Richard Buggs, Reader in Evolutionary Genomics at Queen Mary University of London, has just written an intriguing article in Nature: Ecology and Evolution (28 October 2017), titled, Adam and Eve: a tested hypothesis? Comments on a recent book chapter. It appears that Buggs is unpersuaded that science has ruled out Adam and Eve. He thinks it’s still theoretically possible that the human race once passed through a short, sharp population bottleneck of just two individuals, followed by exponential population growth. Buggs disagrees with the assessment of Christian biologist Dennis Venema, professor of biology at Trinity Western University in Langley, British Columbia, who forthrightly declared in chapter 3 of his 2017 book Adam and the Genome that it is scientifically impossible that the human lineage ever passed through a bottleneck of two, and we can be as certain about this fact as we are about the truth of heliocentrism.

Here’s Buggs’ take-down of the three methods employed by Venema to discredit the possibility of a single primal couple. As a layperson, I have to say it looks as if Buggs has done his homework:

Linkage disequilibrium within populations

…The methods assume that the populations at any given time point are at equilibrium and not expanding exponentially (the authors deliberately exclude the last 10,000 years from this analysis as they know that exponential population growth has occurred in this timeframe). It is hard to see how they could pick up on a short, sharp bottleneck even if one had happened. It would be nice to see this modelled, just to check.

PSMC method

…More recently, some simulations by a graduate student have shown that the PSMC method does not detect short, sharp bottlenecks, such as those caused by a pandemic or natural disaster. Thus I cannot see that PSMC analyses (many more of which have been done on human genomes since the original paper by Li and Durbin) can be cited as rigorously disproving a short, sharp bottleneck.

Incomplete lineage sorting

Venema makes an argument based on incomplete lineage sorting among humans, apes and gorillas, which gives a large estimated effective population size. This argument is not relevant if we are only interested in the human lineage (the occurrence of ILS does not require maintenance of large populations sizes in every lineage after speciation and so does not exclude a bottleneck in the exclusively human lineage).

Buggs adds:

We need to bear in mind that explosive population growth in humans has allowed many new mutations to rapidly accumulate in human populations (A. Keinan and A. G. Clark (2012) Science 336: 740-743). Hyper-variable loci like MHC genes or microsatellites have so many alleles that they seem to defy the idea of a single couple bottleneck until we consider that they have very rapid rates of evolution, and could have evolved very many alleles since a bottleneck.

In his conclusion, Buggs modestly refrains from claiming to have rebutted Venema’s arguments:

The question asked by my religious friends is different to the questions being asked in the studies discussed above. My religions (sic) friends are not asking me if it is probable that humans have ever passed through a bottleneck of two; they are asking me if it is possible. None of the studies above set out to explicitly test the hypothesis that humans could have passed through a single-couple bottleneck. This is what we need to nail this issue down…

If I am missing something, then I would very much like to know. Whilst this issue may seem trivial to many readers, for large numbers of religious believers in the world, this is a critical issue. Do they really face a binary choice between accepting mainstream science and believing that humans have, at some point in their history, all descended from a single couple? I am open to the possibility that they do face this dilemma, but I need more evidence before I am persuaded.

I would be interested to know what biologists think of Richard Buggs’ article. Is he right? Does science still leave open the possibility of Adam and Eve? Over to you.

362 Replies to “Adam and Eve still a possibility?”

  1. Acartia Acartia
    Ignored
    says:

    I’m not qualified to comment on the genetic implications and limitations of small population size, but the bigger question is, when did god institute the “sin of incest”? Obviously, if the current human population are descended from two human anscestors, incest must have been common.

  2. Neil Rickert
    Ignored
    says:

    I’m not a biologist, so I can’t comment on the possibility, though it seems unlikely.

    If you look at where the Australian aboriginals came from, then if there were a single pair, that was a very long time ago. So it doesn’t fit other aspects of the A&E story.

    And then the story is clearly of the genre of fables. So why take it seriously?

  3. stcordova
    Ignored
    says:

    VJ,

    Incomplete lineage sorting

    Venema makes an argument based on incomplete lineage sorting among humans, apes and gorillas, which gives a large estimated effective population size. This argument is not relevant if we are only interested in the human lineage (the occurrence of ILS does not require maintenance of large populations sizes in every lineage after speciation and so does not exclude a bottleneck in the exclusively human lineage).

    Exactly!

    This past June at the Lipscomb University conference, I met Nathaniel Jeanson a Harvard trained biologist. He would also concur with Buggs. So also would Rob Carter who was a biologist and genetic engineer (one of the pioneers of glowing fish).

    If Adam had a lot of Alleles not shared with Eve and vice versa, then I don’t see anything preventing a bottleneck from happening and still allowing the diversity in humans we see today. Jeason and Carter pointed this out in their papers.

    Jeanson pointed out when we study horse breeds where we have very good records of ancestry with bottlenecks that ended up with huge amounts of diversity in the offspring.

    https://answersingenesis.org/noahs-ark/did-darwin-argue-that-species-originated-recently/

    and Carter regarding Adam and Eve:
    https://creation.com/historical-adam-biologos

    As detailed above, one of the arguments from BioLogos is that there has not been enough time to accumulate the mutations found among people today if we came from Adam and Eve. A corollary to that is, we could not survive that kind of mutation load. As I said above, however, this is assuming Adam had no heterozygosity, which is ridiculous. How much created diversity might we assume? One way of estimating this is to look at the number of alleles shared among all world populations. In the HapMap data, every single measured allele falls into this category. Each of these is also biallelic, that is, it has but two alternate letters (A or G, C or T, etc.). Part of this was by design as the HapMap alleles were carefully selected, but this is a good statement about the state of human genetic diversity in general: most variation is biallelic and can be found in most populations. Thus, well over one million heterozygous, biallelic loci must have been present at Babel. These also should have been present at the Flood and at Creation a mere ten generations prior to that. Yet, HapMap did not measure every allele. Since most of the genetic diversity known today can be found among multiple world populations, most of the variation should have been here from the beginning.

    Is it possible for a single person to carry this much diversity? I ran an analysis of the HapMap data to measure the amount of heterozygosity within the HapMap individuals. Population-level differences were slight, with a global average of 4.33 ± 0.234 × 105 (±SD) heterozygous alleles per person. Thus, approximately 30% of all HapMap alleles are heterozygous within each person. If there are 10 million common variants, a single individual would be expected to carry upwards of three or four million heterozygous alleles! Because most people are phenotypically normal, there is no reduction in fitness associated with these high levels of heterozygosity. Why should there be if most of this variation was created by God and engineered into the original genome? I expect Adam had about 10 million or more heterozygous loci and that each of his children had half that much.

    On a side note, in March, I was recruited by John Sanford to study another of Venema’s claims, namely that of nylonase which he uses in his book.

    We (John and I) have, even by the comments of non-creationists here, demonstrated Venema is terribly wrong because we overturned the claims of Ohno’s 1984 PNAS article which Venema uses. Venema uses the nylonase claim a lot in his book and its an embarrassment and shows rather shaky scholarship.

    Our website with our first rough draft will be released shortly.

  4. Robert Byers
    Ignored
    says:

    A few corrections. The natives of Australia were just migrating peoples from Southern India. They probably got there about 2000BC.
    Adam/Eve lived hundreds of years and so did everyone till some time after the flood. So number crunching doesn’t matter if this is ignored.
    Now i know its about a PAIR and can such a pair of brought the present number.
    Look at the Hebrews. from 70 people in Josephs time came some 3 million , i think, at the exodus.
    there is no bottleneck problem. Just a human competence with numbers problems.
    Evolutionism does indeed have problems in denying the very first families of humans and then a few generations before that.
    What about neanderthals and interbreeding by the way. is that in these equations?

  5. Acartia Acartia
    Ignored
    says:

    Robert Byers,

    “Now i know its about a PAIR and can such a pair of brought the present number.”

    This has nothing to do with population growth. But thank you for participating and demonstrating how lame the creationist arguments are.

  6. Neil Rickert
    Ignored
    says:

    Robert Byers: The natives of Australia were just migrating peoples from Southern India. They probably got there about 2000BC.

    From Wikipedia:

    Several settlements of humans in Australia have been dated around 49,000 years ago. Luminescence dating of sediments surrounding stone artefacts at Madjedbebe, a rock shelter in northern Australia, indicates human activity at 65,000 years BP. Genetic studies appear to support an arrival date of 50-70,000 years ago.

  7. phoodoo
    Ignored
    says:

    Neil Rickert:
    I’m not a biologist, so I can’t comment on the possibility, though it seems unlikely.

    If you look at where the Australian aboriginals came from, then if there were a single pair, that was a very long time ago.So it doesn’t fit other aspects of the A&E story.

    And then the story is clearly of the genre of fables.So why take it seriously?

    Yes, I agree with you.

    When people start talking as if its not a fable, when we know the bible was written by people, I think its natural to question their sanity.

    Man could have started by only two people, but if it did, there was no one to write about it at the time.

  8. keiths keiths
    Ignored
    says:

    Neil,

    And then the story is clearly of the genre of fables. So why take it seriously?

    Christians take it seriously because it isn’t merely a creation story to them. It has huge theological implications.

    The story of Adam and Eve is the story of the Fall, and the Fall sets the stage for Christ’s coming. No Fall, no need for Christ. So a Christian who denies the historicity of Adam and Eve needs to come up with another explanation for the Fall.

    Also, to deny the truth of the A&E story calls other parts of the Bible into question.

    For example, Luke makes a point of tracing Jesus’s ancestry all the way back to Adam:

    23 Now Jesus himself was about thirty years old when he began his ministry. He was the son, so it was thought, of Joseph,

    the son of Heli, 24 the son of Matthat…

    <snip>

    38 the son of Enosh,

    the son of Seth, the son of Adam,

    the son of God.

    Luke 3:23-38, NIV

    To admit that Adam and Eve are mythical is to admit that the Gospel of Luke contains a bullshit genealogy.

    The apostle Paul makes repeated references to Adam’s sin. For example:

    18 Consequently, just as one trespass resulted in condemnation for all people, so also one righteous act resulted in justification and life for all people. 19 For just as through the disobedience of the one man the many were made sinners, so also through the obedience of the one man the many will be made righteous.

    Romans 5:18-19

    To deny the truth of the A&E story is to call both Luke and Paul into doubt. That’s a heavy price to pay, and many Christians are unwilling to pay it.

  9. Rumraket Rumraket
    Ignored
    says:

    Adam and Eve was always strictly speaking, possible. Nobody has seriously argued otherwise.
    The argument was always that it would be extremely unlikely for total human genetic diversity to evolve from a single breeding couple.

    You can always just postulate in ad hoc fashion, that all sorts of fantastic types and levels of genetic mutations happened to create all the diversity we see.

    But even if we postulate this happened, it still doesn’t make any sense in context. Never mind the issue of the size of a past bottleneck. Adam and Eve would still have to be primates that evolved from other primate ancestors that share common descent with the rest of the diversity of primates, to say nothing of mammals or the entire diversity of life. It doesn’t make logical sense to imagine that at some rather arbitrary point, a two-human bottleneck happened and from then on, “original sin” was carried with it. Then what of all that idiotic talking snake and magical appletree nonsense? And those two humans, did their parents not belong to the same species or what? Did they not have souls too? Were they not also capable of sin?

    The Adam and Eve story simply doesn’t make logical sense in the context of evolution and common descent. It’s obviously intended to be taken literally, as that is the only way in which it makes even a smidgeon of sense. That there really were two first human beings, that weren’t born by any parent organisms but were divinely created by God. But that never happened, it’s a fable. An old, demonstrably false creation myth.

  10. Corneel Corneel
    Ignored
    says:

    Yes, looks like a academic exercise to me.
    For example, in the Book of Genesis Eve was created from Adam’s rib. Hey, doesn’t that limit the number of autosomal alleles to two? And the X-linked number of variants to one? No, it doesn’t because God can do whatever he wants, so why put restrictions on the genetic variation available to Him?

  11. Allan Miller
    Ignored
    says:

    stcordova,

    If Adam had a lot of Alleles not shared with Eve and vice versa […]

    Then you are hoping for an extreme of heterozygosity that would be unlikely to permit successful F1 meiosis in their offspring. And, you still only have 4 alleles max. This isn’t just an Adam-and-Eve issue either. Every population derived from a pair on the Ark would require whatever ad hoc conditions you try to whistle up to save your story (but not fish, or ducks, or octopus).

  12. RodW
    Ignored
    says:

    I’ve only skimmed the debate on this but it seems to me that Buggs is making the argument that there are complications to calculating bottlenecks from the total heterozygosity at multiple loci in a population and its still possible we had a bottleneck of 2.
    I’ve always thought the argument against A+E was based on individual loci with many alleles. For example the MHC loci has ( I think) about 1600 alleles. A+E could have had at most 4 ( there was a later bottleneck on the Ark). The only way to account for A+E would be to postulate a ridiculously high mutation rate at just the MHC locus or to have God insert in genetic diversity. Either one pretty much gives the game away.

  13. vjtorley
    Ignored
    says:

    Hi everyone,

    I’d just like to clear up a few matters.

    This is not a post about the historicity of Genesis, as a book, but rather, about the possibility of the human race having descended from an original couple (call them Adam and Eve, if you like). I quite agree that if Eve was made from Adam’s rib, then Buggs’ argument that “a single couple can carry with them 0.75 of the heterozygosity of their ancestral population” would be utterly irrelevant. I would also happily grant that if one were to interpret the Genesis account of Noah’s flood as an event which wiped out the entire human race (except for eight people) during the last 5,000 years, then Buggs’ argument that the human population size could have been as small as two people, more than 200,000 years ago, would be cold comfort indeed.

    However, it would be absurd to claim that Genesis must either be 100% historical or 100% mythical. Some statements in the creation narratives of Genesis 1 and 2 may well be highly symbolic, but it is difficult to dispute the fact that the author(s) of Genesis intended to teach that humanity was descended from an original couple. It is also difficult to dispute that St. Paul intended to teach that, for reasons pointed out by keiths above. (I’m not saying it’s impossible, mind you, but it’s very difficult. For example, some Christians have argued that Adam simply means “Everyman”: he’s not meant to be an historical figure. But if Jesus Christ is the New Adam, as St. Paul asserts in Romans 5:15, then why should his historicity matter either?)

    So if there were an historical core to the creation narratives in Genesis, then it would most likely include the existence of a single primal couple. Other elements of the narrative may not be historical. For instance, the creation of Eve from Adam’s rib seems to be based on a Sumerian folk tale: the Sumerian word for “rib” also means “life”. And Noah’s Flood may refer to an actual historical event, but we cannot be sure that it was meant to refer to a universal deluge.

    Rumraket writes:

    Adam and Eve was always strictly speaking, possible. Nobody has seriously argued otherwise.

    The argument was always that it would be extremely unlikely for total human genetic diversity to evolve from a single breeding couple.

    I beg to disagree. Here’s what Professor Jerry Coyne wrote on the question of Adam and Eve, back in 2011:

    We can all argue about whether Jesus was a parthenogenetic being produced without physical insemination, and whether he became reanimated a few days after death, but getting direct evidence for those “miracles” is well-nigh impossible, and so we argue against them on the grounds of improbability. But there’s one bedrock of Abrahamic faith that is eminently testable by science: the claim that all humans descend from a single created pair — Adam and Eve — and that these individuals were not australopithecines or apelike ancestors, but humans in the modern sense. Absent their existence, the whole story of human sin and redemption falls to pieces.

    Unfortunately, the scientific evidence shows that Adam and Eve could not have existed, at least in the way they’re portrayed in the Bible. Genetic data show no evidence of any human bottleneck as small as two people: there are simply too many different kinds of genes around for that to be true. There may have been a couple of “bottlenecks” (reduced population sizes) in the history of our species, but the smallest one not involving recent colonization is a bottleneck of roughly 10,000-15,000 individuals that occurred between 50,000 and 100,000 years ago.

    I don’t think Professor Coyne regards the existence of an original primal couple as a possibility. Evidently Dr. Richard Buggs disagrees with him. So who is right?

    RodW writes:

    …[T]he MHC loci has ( I think) about 1600 alleles. A+E could have had at most 4 ( there was a later bottleneck on the Ark). The only way to account for A+E would be to postulate a ridiculously high mutation rate at just the MHC locus or to have God insert in genetic diversity.

    Dr. Buggs has answered this objection in his article:

    Hyper-variable loci like MHC genes or microsatellites have so many alleles that they seem to defy the idea of a single couple bottleneck until we consider that they have very rapid rates of evolution, and could have evolved very many alleles since a bottleneck.

    Allan Miller argues that had Adam and Eve been sufficiently heterozygous to account for the diversity we observe today, they would have possessed “an extreme of heterozygosity that would be unlikely to permit successful F1 meiosis in their offspring.” Could Dr. Miller please explain why? I’d like to hear more about this. (Dr. Miller also objects to the Ark story, but as I’ve argued above, that’s peripheral to the topic of this post.)

  14. Corneel Corneel
    Ignored
    says:

    vjtorley: Dr. Miller

    Wow, moving up.

    Hey I am a Dr. too!

  15. vjtorley
    Ignored
    says:

    Hi everyone,

    Further news. I’ve just located a recent post by Professor Jerry Coyne (dated December 27, 2016) which raises what he considers to be a fatal objection to the claim that humanity is descended from an original primal couple.

    Further, as I wrote in the thread above, were Adam and Eve the genetic ancestors of all of us, then

    . . . all the genes of every living human should “coalesce” back to the same time and the same two people. But we don’t see that either: each gene segment had its ancestor at a different time (and often at a different place) in the past: the Y chromosome, for instance, coalesces back to an ancestor who lived about 60,000 years more recently than the female ancestor who bequeathed us the genes in our mitochondria. So this solution is also untenable.\\

    And that solution is untenable even if you think we all inherited Adam’s Y chromosome (if we’re male) and Eve’s mitochondrion.

    Coyne’ argument is a little out-of-date here, however. First, the date of Y-chromosomal Adam has been revised backwards in the light of recent discoveries, and it now appears that mitochondrial Eve and Y-chromosomal Adam could have lived at the same time, after all.

    Second, Mitochondrial Eve is defined as the matrilineal most recent common ancestor (MRCA) of all currently living humans, while Y-chromosomal Adam is the most recent common ancestor (MRCA) from whom all currently living humans are descended patrilineally. But if we include Neandertal man and Denisovan man in our definition of “human,” then the most recent common ancestor would have lived much earlier – at least 400,000 years ago, and perhaps 800,000 years ago.

    To be fair, however, I should point out that recent evidence suggests that these species may not have been fully human, after all. To quote Wikipedia:

    In 2017, it was shown that modern humans have gone through particularly extensive DNA methylation changes in the voice box (larynx) genes while no such changes have been observed in the Neanderthal or in the Denisovan. This study suggested that the human vocal apparatus, previously shown to be optimal for speech, has gone through vast morphological changes after the split from archaic humans, and could thus be unique to modern humans.[35]

    Recent discoveries of evidence for culture among the later Neandertals may simply be due to the fact that they interbred with Homo sapiens, and thus some of their offspring would have thereby acquired the ability to speak, enabling them to transmit complex and sophisticated concepts down through the generations.

    Third, Buggs responds in his article to the objection regarding coalescence times:

    Because a single couple can carry with them 0.75 of the heterozygosity of their ancestral population, we would not expect an extreme number of coalescence events at the bottleneck. Furthermore, those that are there were would be smeared out over a long period of time around the bottleneck.

    So it seems that Coyne’s argument is far from being a knock-out blow against the Adam-and-Eve hypothesis described by Buggs: a single primal couple whose descendants underwent exponential population growth.

  16. GlenDavidson
    Ignored
    says:

    The talking snake seems a tad unlikely.

    Glen Davidson

  17. vjtorley
    Ignored
    says:

    I agree.

  18. Alan Fox Alan Fox
    Ignored
    says:

    vjtorley,
    Not that I think Thomas Jefferson was any kind of saint, but his approach to the Bible makes sense to me. Had you thought of considering his approach to editing?

  19. Erik
    Ignored
    says:

    Alan Fox,

    What if Thomas Jefferson is not any kind of saint precisely because of his approach to the Bible?

  20. Tom English Tom English
    Ignored
    says:

    GlenDavidson: The talking snake seems a tad unlikely.

    All of the talking snakes known to us are intellectualistic defenders of imbecilic institutions. But we cannot prove that imbecilic institutions predate talking snakes. Indeed, there is scientific evidence that talking snakes are not merely the defenders of imbecilic institutions, but also the creators of them (see this unpublished paper that someone uploaded to a preprint archive).

  21. Alan Fox Alan Fox
    Ignored
    says:

    PS @ Vincent
    You may recall a commenter at Uncommon Descent, Jon Garvey, a retired MD and (now I come to think, I’m not sure if he wasn’t a Catholic) committed Christian who, when I asked what the point of the Old Testament was, gave a very dusty and disappointing answer. Bear with me and I’ll try and find it.

    ETA here

  22. Alan Fox Alan Fox
    Ignored
    says:

    Erik,
    Well, I don’t get to choose! 🙁

  23. Alan Fox Alan Fox
    Ignored
    says:

    @ Erik
    *penny drops*
    I don’t get to choose because I’m no saint either! 😯

  24. Allan Miller
    Ignored
    says:

    Corneel,

    Wow, moving up.

    Hey I am a Dr. too!

    And I’m not – never finished my PhD! Just Random-Internet-Gobshite Miller, I’m afraid!

  25. Alan Fox Alan Fox
    Ignored
    says:

    vjtorley:…ability to speak, enabling them to transmit complex and sophisticated concepts…

    Not sure that link has been fully established.

  26. Mung Mung
    Ignored
    says:

    Erik: What if Thomas Jefferson is not any kind of saint precisely because of his approach to the Bible?

    LoL.

  27. Allan Miller
    Ignored
    says:

    vjtorley,

    Allan Miller argues that had Adam and Eve been sufficiently heterozygous to account for the diversity we observe today, they would have possessed “an extreme of heterozygosity that would be unlikely to permit successful F1 meiosis in their offspring.” Could Dr. Miller please explain why?

    It’s a bit of a guess, to be honest, and I could easily be wrong.

    Successful meiosis depends upon a high degree of homozygosity between the parental chromosomes. This is necessary because the mechanism of crossover requires that a significant region of sequence homology exists on both chromosome sets. It is one reason for the sterility of hybrids despite the frequent ‘vigour’ of the hybrid organism itself. So, if one wishes to shove all the heterozygosity in a population into one breeding pair, this may take it over the threshold. It’s not a ‘hard’ barrier – interfertility diminishes towards zero with increasing genetic distance; it’s not either 100% or zero.

    It’s not an issue for any two random members of the population because they will only be sampling the heterozygosity in the population, not possessing its entirety.

    ([“Dr”] Miller also objects to the Ark story, but as I’ve argued above, that’s peripheral to the topic of this post.)

    I don’t see why, other than the fact that Creaionists seem less interested in other species. If we could detect ‘couple’ bottlenecks, we’d detect the Ark.

  28. John Harshman John Harshman
    Ignored
    says:

    vjtorley: Dr. Buggs has answered this objection in his article:

    Hyper-variable loci like MHC genes or microsatellites have so many alleles that they seem to defy the idea of a single couple bottleneck until we consider that they have very rapid rates of evolution, and could have evolved very many alleles since a bottleneck.

    That’s nice, but there are more than four MHC alleles shared by humans and chimps. More than four are shared with gorillas too. So much for the extreme bottleneck.

  29. Allan Miller
    Ignored
    says:

    But … if we were supposing A & E to have been simply descended from a prior population, we might wonder how come they were so distantly related as to contain all of modern heterozygosity. Despite being a bottleneck, they did not reduce the variation in the way a ‘random’ pairing would, still less a pair from related stock. It seems a little ad hoc. Can two individuals have an Ne equal to that of modern humans (he asked, hoping a passing population geneticist might hear)?

  30. RodW
    Ignored
    says:

    John Harshman: vjtorley: Dr. Buggs has answered this objection in his article:
    Hyper-variable loci like MHC genes or microsatellites have so many alleles that they seem to defy the idea of a single couple bottleneck until we consider that they have very rapid rates of evolution, and could have evolved very many alleles since a bottleneck.

    That’s nice, but there are more than four MHC alleles shared by humans and chimps. More than four are shared with gorillas too. So much for the extreme bottleneck.

    Of course Buggs had to say something like that but I think when you look in detail at the numbers it doesn’t work, to say the least. His model would predict that there would be ~4 alleles spread uniformly among ethnic groups that would make up, say 90% of the alleles, with another handful at say 5% and most of the 1600 at an exceedingly small %. That’s what you’d get from a rapidly expanding population of 2.

  31. Corneel Corneel
    Ignored
    says:

    Allan Miller: Just Random-Internet-Gobshite Miller, I’m afraid!

    You certainly had Vincent fooled 😀

  32. Tom English Tom English
    Ignored
    says:

    John Harshman: That’s nice, but there are more than four MHC alleles shared by humans and chimps. More than four are shared with gorillas too. So much for the extreme bottleneck.

    Well, you cannot prove that those alleles did not reemerge after the bottleneck. Glory be to the God of the Gaps!

  33. Rumraket Rumraket
    Ignored
    says:

    @vjtorley

    If Jerry Coyne really meant to say that the Adam and Eve story isn’t possible in principle, then Jerry Coyne is wrong. It is a probability argument and it always was. Genetics is about probabilities and statistics.

    A charitable interpretation of Coyne is that he’s speaking colloquially and when probabilities get low enough, we might as well just say it’s impossible. My guess is if you pressed him on it, he’d agree with what I wrote.

  34. colewd
    Ignored
    says:

    vjtorley,

    This needs to change, according Christian biologist Dennis Venema writing in the 2017 book Adam and the Genome. Chapter 3 of this book claims that three population genetic studies give independent estimates that the population size of humans has never dropped below around 10,000 individuals. Venema declares that a bottleneck of two is impossible, and this is a fact of comparable scientific certainty to heliocentrism. He gives his Christian readers a stark choice between embracing mainstream science, or sticking with untenable beliefs about an ancestral couple.

    Is Dennis assuming that humans and chimps share a common ancestor?

  35. Flint
    Ignored
    says:

    colewd:
    vjtorley,

    Is Dennis assuming that humans and chimps share a common ancestor?

    I think that depends on what you mean. Certainly there wasn’t a single species which branched into modern humans and modern chimps. There have, according to the fossil record, been multiple human ancestor species (maybe a dozen or more) between us and the human/chimp common ancestor.

    The chimp side, according to my reading, suffers from the fact that the habitat preferred by that subtree militates against fossil formation. But almost surely there have been many intervening species on the chimp side as well.

  36. Flint
    Ignored
    says:

    Rumraket:
    @vjtorley

    If Jerry Coyne really meant to say that the Adam and Eve story isn’t possible in principle, then Jerry Coyne is wrong.

    True if your intent is to focus on the possibility of a single ancestral pair, and look at the genetic possibilities from there. If by “the Adam and Eve story” you’re including the apple, the snake, the Eden geography etc, then I’m with Coyne.

  37. Steve Schaffner
    Ignored
    says:

    The argument about total heterozygosity is a red herring. A tight but short bottleneck has a relatively modest effect on heterozygosity, but a dramatic effect on the distribution of allele frequencies. A bottleneck of two individuals eliminates all frequencies at less than 25% frequency, which is where the great majority of variants are. I doubt anyone has ever made a formal test, but having played around with simulations I think an absolute minimum of several hundred thousand years would be required to generate something like the observed frequency spectrum for humans; half a million years is a more plausible lower bound.

    Buggs is right that existing tests have not been tested rigorously against an ancient Adam and Eve scenario. On the other hand, no one has shown that such a scenario would be undetectable by those tests either; it’s just not a scenario most geneticists are interested in. It’s not clear how many creationists are interested in a half million year old Adam anyway.

  38. keiths keiths
    Ignored
    says:

    colewd,

    Is Dennis assuming that humans and chimps share a common ancestor?

    He doesn’t assume it, but he accepts it. It’s a solid scientific conclusion, and he isn’t a creationist crackpot.

  39. vjtorley
    Ignored
    says:

    Hi Rumraket,

    If Jerry Coyne really meant to say that the Adam and Eve story isn’t possible in principle, then Jerry Coyne is wrong. It is a probability argument and it always was. Genetics is about probabilities and statistics.

    A charitable interpretation of Coyne is that he’s speaking colloquially and when probabilities get low enough, we might as well just say it’s impossible. My guess is if you pressed him on it, he’d agree with what I wrote.

    I can’t speak for Professor Coyne, but it seems that Professor Venema really does think Adam and Eve are absolutely impossible, according to Dr. Richard Buggs:

    A few months ago, I was reading a new book by Dennis Venema and Scot McKnight entitled Adam and the Genome. I was surprised to find a claim within the book that the past effective population size of humans has definitely never dropped below 10,000 individuals and that this is a fact of comparable scientific certainty to heliocentrism.

  40. vjtorley
    Ignored
    says:

    Hi Allan Miller,

    Sorry for calling you “Dr.” by mistake. In any case, the most important thing is that your supervisor thought you were good enough to invite you to start a Ph.D. People have all sorts of reasons for not finishing one.

    But … if we were supposing A & E to have been simply descended from a prior population, we might wonder how come they were so distantly related as to contain all of modern heterozygosity. Despite being a bottleneck, they did not reduce the variation in the way a ‘random’ pairing would, still less a pair from related stock. It seems a little ad hoc.

    I suppose a theistic evolutionist could always reply that part of the reason those two individuals were allowed to survive the bottleneck event was in order to preserve heterozygosity. But in any case, Steve Schaffner’s remark above that “[a] tight but short bottleneck has a relatively modest effect on heterozygosity, but a dramatic effect on the distribution of allele frequencies” is certainly pertinent.

  41. vjtorley
    Ignored
    says:

    Hi Steve Schaffner,

    Buggs is right that existing tests have not been tested rigorously against an ancient Adam and Eve scenario. On the other hand, no one has shown that such a scenario would be undetectable by those tests either; it’s just not a scenario most geneticists are interested in. It’s not clear how many creationists are interested in a half million year old Adam anyway.

    FYI, Dr. Ann Gauger believes in a two-million-year-old Adam and Eve. She regards Homo erectus as the first true human being. I corresponded with her recently on this subject.

  42. John Harshman John Harshman
    Ignored
    says:

    vjtorley: FYI, Dr. Ann Gauger believes in a two-million-year-old Adam and Eve. She regards Homo erectus as the first true human being.

    Why? And does she think that other, earlier hominids are unrelated?

  43. Tom English Tom English
    Ignored
    says:

    Dr. English believes in the Battlestar Galactica account of mitochondrial Eve because a pair of alien scientists, Elohim and Allah, telepathically conveyed to him conviction of its truth.

  44. J-Mac
    Ignored
    says:

    vjtorley: FYI, Dr. Ann Gauger believes in a two-million-year-old Adam and Eve. She regards Homo erectus as the first true human being. I corresponded with her recently on this subject.

    Really? Based on what evidence? Not biblical genealogy? Because if she did, there would be about 20 000 generations missing from Adam to Jesus 😉

  45. Robert Byers
    Ignored
    says:

    Neil Rickert: From Wikipedia:

    This is more error and incompetence. They are , trying, to date human occupation by other things is admitting to having no evidence for human occupation concepts.
    its just tired old ideas about dating decay rates etc etc in dirt.
    First one needs the occupation of australia by creatures after the flood. then a rise in sea levels to make no more migration for landwalkers. Including a lot of change in the original australia. Then later minor, tiny, tribes of South Indians migrating in along the coasts. in fact it might of been as late as 1500BC.
    they never became sucessful there in population growth.

  46. Robert Byers
    Ignored
    says:

    Rumraket,

    Your wrong.
    its the witness of gods word.
    Its reasonable to see everyone from a original created pair. Unlike evolutionism which , forever, must have a population extending backwards in any bodyplan we must of had to justify evolution.
    There is no problem with bodyplan diversity in humans if one has imagination for other options for bodyplan changes. like instant changes happening to some tribe upon migration and this changing, naturally, the DNA.
    i think simple math would go against a evolutionist concept of the original population groups for mankind as they need them. maintaining a purity too.

  47. Robert Byers
    Ignored
    says:

    Corneel:
    Yes, looks like a academic exercise to me.
    For example, in the Book of Genesis Eve was created from Adam’s rib. Hey, doesn’t that limit the number of autosomal alleles to two? And the X-linked number of variants to one? No, it doesn’t because God can do whatever he wants, so why put restrictions on the genetic variation available to Him?

    I understand the hebrew word for RIB in genesis is not demanding a actual RIB
    by the way, very speculative, but i have opined that the RIB was actually a reproductive ability that adam had to self reproduce.
    this thus explaing his surprise at eVE and seeming not to wonder why there was no FEMALE for him when female/male pairs were obvious amongst the animals.
    then its poetic the women , who is very much about reproduction, was created from this RIB.
    speculation!

  48. keiths keiths
    Ignored
    says:

    Byers, to Rumraket:

    Your wrong.
    its the witness of gods word.

    Robert,

    It’s odd that in this thread you’re be relying on the truth of God’s word, while in the other thread you’re relying on its falsehood.

  49. Rumraket Rumraket
    Ignored
    says:

    vjtorley:
    Hi Rumraket,

    I can’t speak for Professor Coyne, but it seems that Professor Venema really does think Adam and Eve are absolutely impossible, according to Dr. Richard Buggs:

    It doesn’t seem to me that what you quote is in conflict with what I say. I would regard statements about probabilities as statements of facts. As in I don’t see a contradiction between the terms:
    A. It is a fact that there was no Adam and Eve.
    B. It is unfathomably unlikely that there was an Adam and Eve.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.