I should add that the whole analysis is very tightly dependent most sharply on how many children Adam and Eve have. If they have, say, 8 kids, and then it goes down to just 0.4% growth from 2 centuries, then down to 0.04% long term, it would be very hard to detect.
Having 8 kids in one family is not at all implausible.
And having 3 of them die is quite within reason in a world without doctors and lots of physical risks…
The question was discussed in the thread “My Theory about the Flood”. For the sake of accessibility to interested readers I develop my argument with pleasure in the follow:
First of all let me remark that about 362,000 humans in God’s Image are created each day around the world presently, that is, in “a separate moment in time from humanity’s initial creation”. So to this extent my interpretation regarding Genesis 9:6 is nothing bizarre.
Presumably you are astonished because I claim that Genesis 9:6 refers to the creation of Image Bearers the same way as God created the first ones (“Adam and Eve”). i.e.: by endowing human-like animals with capability to freely love Him.
Notice however that Genesis 6:2-4 explicitly refers to human beings called “sons of God” the same way as Adam is called “son of God” (Luke 3:38): This means that the “sons of God” in Genesis 6:2-4 were created the same way as Adam was created but in a separate later moment.
Gordon Wenham [Word Biblical Commentary I, Genesis 1-15, Word books: Dallas, 1987] following Claus Westermann claims:
Genesis 9:3-7 explain “why human life is specially protected, but animal life is not”, and proclaim “the inviolability of human life” that follows from “the unique right of God over life and death”: “Every single violation of this limit, be it based on national, racial or ideological grounds is here condemned” [p. 251]. Indeed the remark in Genesis 9:3 concerning food indicates a degree of distinction between humanity and the animal kingdom that was lacking in the vegetarian diet of Genesis 1:29 [p. 263-264]; and in Genesis 9:5-7 appears for the first time the prohibition of killing any creature belonging to humanity because mankind is made in the image of God.
One may wonder why this distinction and this prohibition were omitted in Genesis 1:26-29, as the “image of God” is mentioned for the first time. And even more astonishing is that the prohibition was omitted in Genesis 4:15, where to protect Cain God does not proclaim that he shares human blood and belongs to mankind but “put a mark on Cain so that no one who found him would kill him.” A reasonable explanation for such an “omission” in divinely inspired Scripture is that a sharp distinction between human and animal life would not fit with the ontological status of pre-diluvian Creation; such a distinction is appropriate only once all human-like animals on the earth were transformed into human persons. Since this allegedly happened after the Flood, only then (Genesis 9:5-7) God categorically proclaims that the right to life, foundation of the personal rights, is defined by the belonging to humanity. And here we meet to some extent the interpretation of Hendel, R. S.: The Flood narrative with its introductory pericope of the “sons of God” ends ordering “the human cosmos” [Of Demigods and the Deluge: Toward an Interpretation of Genesis 6:1-4, Journal of Biblical Literature, Vol. 106, No. 1 (1987), pp. 13-26, and References therein]. The ordering happens mainly by means of an explicit formulation of the foundation of rights and law.
Please let me know whether I have answered your question or you desire further clarifications.
I won’t derail this very important Buggs-Venema-Swamidass-Schaffner thread further with these matters, particularly if this has already been discussed elsewhere on the Forum (at length, apparently, during the months when I took a break from the Forum).
My opinion on your theory does not matter in the least, but I do find it quite implausible. I will leave it there. If you wish to continue, you can start a new topic.
I would appreciate knowing why you find it implausible. Since the issue is related to transmission of original sin I would like to suggest you post the reasons in this other thread.
Nonetheless I think it would be also fitting posting here since in the end the question at the core of the debate seems to be:
Is it theologically necessary that all Image Bearers are genetically or at least genealogically descended from a single couple?
I would be thankful to know your answer to this question.
You’re probably a super nice guy, so I don’t want to offend you, but in general when people come to the Forum here with their own pet theories that are not mainstream, I don’t find it particularly useful to spend much time engaging with them.
This is because
[1] the chances of my persuading such a person are slim to none, and
[2] there are no lurking readers who might be convinced by what I spend valuable time writing, because lurking readers are very unlikely to be in the same camp as the pet-theorist.
This is why I have not spent literally one minute even reading the thread “A.Suarez’s Treatment on a Pope’s Formulation for Original Sin’s Transmission!” despite its high traffic. Life is short, I already spend far too much time on this Forum, and I need to manage my time more wisely; I truly mean no offense to you. If you manage to publish an article and your ideas go mainstream, perhaps I’ll go back and read up on them.
But to respond ever so briefly, I like to believe that the ideas of fallenness and of God’s image actually have some real-world behavioral correlates. So as for the idea that, magically, presto change-o!, all humans became image-bearers through some ad-hoc miracle not recorded clearly in the Bible, I find it implausible and not worth pursuing further.
But I certainly wish you well, brother!
Peace,
AMW
Bill, it seems we both agree that Writing conclusively demonstrates the presence of humans who are in the Image of God.
I would be happy if you can argue convincingly that Language is a feature capable of sharply distinguishing Image Bearers from human-like animals as well. But (“Chomsky, non-Chomsky”) the debate in this thread rather suggests that it is not.
In any case moving God’s creation of the first Image Bearers from 3500 BC to 50’000 BC does not seem to be relevant for the core question in this thread, that is:
Can all Image Bearers of all times be considered genetic or at least genealogical descendants of a single couple, who God created ex novo or by making human-like animals in His Image?
And after all:
Do you think that setting the creation of the first Image Bearers at 50’000 BC instead of 3500 BC fits better to the Bible or allow us to avoid some important theological problem?
If NOT, let us keep to 3500 BC as the safest proposal, at least for the time being.
If YES, please explain why.
God didn’t see fit to give us any indication in the Bible as to exactly when we became image bearers so you can’t say which is better 50,000 years or 3,500 years. Knowing exactly when does solve or create any theological problem that I can see. If 3,500 BC makes you feel safe then by all means keep to that date.
No, there is evidence, but it comes from disciplines other than genetics. Steve referred briefly to it here:
We have an example of a bottleneck that sheds light on the discussion. The Toba super-eruption 74 Kya affected the climate for about 5,000 years and precipitated a near-extinction event for H. sapiens. Another 5,000 years later, the human population experiences “explosive” growth as it departs the Levant and begins migrating across the globe. In short, we have geologic evidence of a natural disaster that precipitated climate change and caused a bottleneck, and we have evidence of climate change that affected population growth for millennia.
Genetics indicated a bottleneck in the human population just prior to the “Out of Africa” event, and other sciences provided corroborating evidence to verify that finding. Any hypothesis involving a bottleneck to two individuals followed by explosive growth cannot rely on genetics alone. As Steve asked, what sort of natural disaster could fit such a scenario? The science of genetics may not be able to rule out a single-couple bottleneck of that sort, but surely climatology, geology, archaeology, etc., have something to say about it.
No one is trying to distinguish humans from animals in this thread. That’s worthwhile discussion, but it’s not the focus at the moment. We’re simply pointing out that two people could not invent language. It’s an absurd concept. Any scenario that involves the special creation of Adam and Eve – whether in the distant past or in the fourth millennium B.C.E. – requires that God implant such knowledge in their minds. It’s a re-run of the “creation with appearance of age” idea, with one major difference: now we are talking about human beings, rather than inanimate objects like trees or rocks or distant stars. In any case, once we resort to that sort of explanation, science is out the window anyway, so why even bother to worry about scientific evidence?
On your remark about newborns and the severely disabled, this depends on one’s view of the image of God. If one takes Gen. 1:26-28 to be a statement of vocation or purpose, then none of us functions properly as the image. None of us love God or others as we should, and none of us perfectly reflect his goodness and moral character. This applies to everyone, newborns and the disabled and scientists alike. I realize this may conflict with some Catholic doctrines, which is probably where the disconnect lies.
Exactly. This is a problem for all “recent Adam” scenarios. Were human beings prior to 6,000 years ago ignorant of all moral principles? Was human culture prior to the Fall sinless? The problems are endless.
Let’s take a break from these discussions for Holy Weekend. I’m locking the thread temporarily.
According to Genesis, God had not caused it to rain upon the earth. So, drought?
Thanks for this thread, I have been greatly enjoying how informative it is!
Wellll… This is perhaps stating the case a bit too strongly. Identical twins, deaf children, and fantasy writers invent languages all the time. I would submit that if you left two modern humans to be raised by wolves on a deserted island (if they managed to survive) they would be more likely than not to invent a language.
That said, I don’t find it probable at all that the development of language in human history was an abrupt shift from non-language to language. So if that’s all you meant, we agree.
We don’t even know enough yet to be able to tell if whales like orcas have true language or not. I think they probably do, personally. It’s entirely possible the only reason they haven’t invented spaceships yet is their lack of opposable thumbs…
Perhap octopuses will. Or perhaps did, if you have seen the movie Arrival.
Ah, but the twins and the fantasy writer have the advantage of already possessing language. On the deaf and those raised by wolves, they certainly would invent ways to communicate, but would it be language? Helen Keller didn’t have language until Ms. Sullivan taught to her, although she certainly communicated with her parents before then. There is a difference between language and communication. Animals have forms of communication, but they lack language.
In human communication, you have the case of pidgin systems that can eventually evolve into creole languages. Like the cases mentioned above, pidgins are invented by speakers of other languages as a communication bridge, not created in a linguistic vacuum. It still stands that full-fledged languages (i.e. creoles from pidgins) require communities of speakers and new ones take generations to develop, they aren’t invented de novo by a couple speakers.
Isn’t the main difference between a pidgen and a creole whether you have kids growing up speaking it as a primary language? Kids’ brains naturally do things with language; if they don’t have one, they’ll invent one. It’s not unreasonable to call it an instinct, despite how often that term has been misapplied.
It is hard to imagine realistic circumstances that would put two people in a linguistic vacuum, modern day or not. But I stand by the statement that their communication would be likely to become a language, supposing they started young enough that their brains had full potential for language.
Just curious how you’d define this difference? Grammar? Abstract concepts? And how do you know? Do you assume humans would be able to recognize non-human language as such on hearing it? What about sounds that are outside the human range of hearing?
There are significant differences in levels of complexity too. Pidgins are rudimentary and not sufficient for all the communicative tasks of fully developed languages. But in certain contexts (often among displaced people from multiple groups, like when you had slavery in the Caribbean) where children grow up in an environment where family social bonds and generational continuity are disrupted, a local pidgin can evolve into a creole acquired by the children of speakers of diverse languages as their first language. But in those cases, new grammatical features emerge to accomplish the things speakers need to accomplish in order to communicate.
I don’t think this is true if they have never acquired a first language. Obviously you can’t run experiments, but there are several cases involving extreme abuse and neglect, like “Jeanie.” An infant brain needs exposure to language to develop the pathways that make language processing possible.
Here are some pretty good lecture notes I found, if you are interested: https://www.staff.ncl.ac.uk/joel.wallenberg/NatureOfLanguage/lecture9.pdf
Right, I was (not very clearly) trying to say that kids, given a pidgen, will automatically add levels of complexity and grammatical features to make it a real language. It’s not something that takes real long, and it’s not the adults making it happen or planning it.
Yes; I would not argue that someone in a ‘linguistic vacuum’ who didn’t have anybody to communicate with would naturally develop language. But if you put a cluster of kids together I think they would. The example of Nicaraguan Sign Language shows that kids can develop a language shockingly fast. The issue of infant development is tricky, and I’ve never claimed anything more than 50%+ “likely,” but two people inventing a language is far from impossible.
Thanks for the resource, will check it out!
It is hard to imagine! I get the feeling that we basically agree, but all these hypotheticals keep getting in the way. In the only example we have of language evolving from non-language, the process required many many thousands of years. I sincerely doubt it could be accomplished in one lifetime by two kids on an island. I also sincerely doubt we’ll have the opportunity to test the hypothesis, so who knows?
Basically all of the above. How do I know? I don’t! I’m just taking the experts’ word for it. Of course, maybe tomorrow they will change their minds, in which case I will change my mind, too. Haha. Here is one expert’s idea of what the evolution of grammar might have looked like:
Each step corresponds to a functional communication system, although not as elaborate and rich as the modern one. They roughly resemble the stages of child language acquisition, where recursivity and flexibility are late additions.
“No one”. Really?
You got me! haha. But what we are discussing is the difference between “communication” and “language,” not the difference between humans and animals. No one in the thread (to the best of my memory, since I’m too lazy to look back through all the posts) brought that up until you said:
We can kick it around a bit, if you like. Since the imago Dei is not specifically defined in Scripture, traditional discussions of it usually came down to the question, “What makes us different from the animals?” The most common reply was reason/rationality, although other qualifications often were added, such as conscience, spirituality, free will, or personhood.
However, a more recent conception of the image of God is the royal/functional interpretation, such as we find in Middleton, Walton, Wright, and others. This interpretation views the image as mankind’s vocation, not an inborn quality. Thus, in this interpretation, the image of God has nothing to do with what makes us different from the animals, and everything to do with God’s intended purpose for mankind, a purpose that was rendered impossible for us to fulfill when we fell into sin.
I happen to subscribe to this latter interpretation. I’m curious how it has been received by Catholic theologians and scholars. Do you think it is compatible with Catholic doctrine?
Many thanks for this thoughtful answer!
Me too I subscribe the interpretation of the image as “mankind’s vocation” as you can see in Section 7.2 of this article.
This view is also strongly supported by Pope John Paul II and Karl Barth regarding Marriage as original vocation and sacrament.
And by Popes Benedict XVI and Francis regarding work as primeval divine vocation of mankind.
However in the thread on Original Sin’s Transmission new insights regarding the meaning of imago Dei in Scripture have been developed. For the sake of convenience in quoting I will answer this your comment there.
I didn’t see your reply, but I looked over your materials and the comments in that thread that specifically mentioned imago Dei or image of God, and I will reply to you there. This thread is already hard enough to follow, no thanks to my own off-topic meanderings.
Hi all,
I have just published another blog post on this issue at the Nature Ecology and Evolution Community here:
best wishes
Richard
Dear @DennisVenema
I am very grateful to you for your response to my original email and blog about the possibility of a bottleneck in the human lineage, and for the discussion that we have had in blogs and on this forum. Your work has helpfully highlighted an area of misunderstanding of current science that is probably shared by many, and it has been extremely informative to all of us to debate this issue and establish what current genomics does and does not show about past human population sizes. All of us have learned a great deal from this.
It is clear to me, as someone who has followed this debate closely and participated in it, that you (like me) now understand the field a lot better than you did before 2017. When you wrote Adam and the Genome you clearly believed that genomic evidence – from the case of the Tasmanian devils, from PSMC analyses, from the Tenesa et al study of linkage disequilibrium, and from allele counts – meant that it was almost impossible that humans had ever passed though a bottleneck of two since diverging from chimpanzees. You left your readers in no doubt about this.
In contrast, your more recent contributions on this forum show that you have now realised that the evidence that you cited in Adam and the Genome does not support this claim. You now realise that the studies you cite did not test a single-generation bottleneck of two. Your new understanding is clear to me as someone who has followed the discussion on this forum in detail, and weighed up what you have said and what you have not said, and what you have implied. Please do correct me if I have misunderstood you and I am drawing a wrong conclusion, as I have had to “read between the lines” in places to come to the conclusion that you realise that every one of these lines of evidence does not support the claim.
Assuming that I have understood you correctly, I think it is my responsibility to encourage you to make a clear public statement correcting what is erroneous in Adam and the Genome. I do this on behalf of readers of Adam and the Genome who will not have the time to read through the the debate on this forum (which is now much longer than chapter 3 of your book), but who are honestly seeking to understand what current science says and does not say about human population history. Not only will this be of service to your readers, but your reputation as reliable communicator of science will be enhanced by such a statement.
Yours sincerely,
Richard
I support what Richard has said. It is clear that when you wrote Adam and the Genome you were taking the published literature at its word, most of which said our population at the time of our split from chimps had an effective population size of 10,000. This seemed solid, as a number of different analyses yielded similar numbers. However, you made an extreme claim when you said that the certainity we could not have come from a bottleneck of two was as certain as heliocentricity.
Why this went wrong should be a lesson to all scientists: it is dangerous to extrapolate or over-interpret data, to go beyond what has been explicitly tested. No one had explicitly tested a bottleneck of two; it was the received knowledge that of course we couldn’t have come from two. Evolutionary theory said species were formed by progressive differentiation from an ancestral population. The claim was made that current genetic diversity could not be explained under standard assumptions if the species started from two. And that is true for recent origins. Standard assumptions won’t work for a young origin of two.Therefore it was not even worth examining, most assumed. But that conclusion was wrong, as we have seen.
Richard gave a very good summary at Adam and Eve: lessons learned | Nature Portfolio Ecology & Evolution Community.
Because the claim that we could not have come from two is wrong, and because that claim impacts the faith of many Christians, with corresponding doctrinal effects, it would be very helpful, even important, to set the record straight. This is not just a matter of a scientific dispute. All we are asking for is a public statement something like this: In a prolonged discussion with my colleagues it has become apparent that the claim that we had to originate from a population of 10,000 was never sufficiently or completely tested. Further analysis has indicated that it is possible that we could have come from a bottleneck of two.
Hi Richard,
Thanks for your comments. Sorry I’ve been slow to respond.
I feel like I’ve gone over this before, but perhaps a recap would be in order.
In AatG I defend two claims - (1) that as our species, Homo sapiens (anatomically modern humans or AMHs), comes into being, we do so as a population. This is the “heliocentric” quote.
I also say that (2) the dip to ~10,000 seems to be the lowest our lineage experienced over the last 18 MY, based on the methods applied to date.
Both of these statements remain accurate. Our discussion has led us to agree that a 2-person bottleneck for the lineage leading to present-day humans is not plausible within the last 700,000 years or more. This is well before AMHs appear in the fossil record. So, point (1) stands, even if one might differ over just how “heliocentric” that certainty is.
Point (2) also stands. I’ve learned a bunch from our discussions - and I’m grateful for it! - but nothing we have uncovered provides any positive evidence for a 2-person bottleneck (or even a sub-~10,000 bottleneck) at any point over that timeframe. So, it still would seem that the ~10,000 number was the low point.
What we have established is that a very sudden bottleneck to 2 followed by exponential population growth might escape detection using current methods if it occurred before 700,000 years ago. That is interesting, but it does not change the points I made in the book. It still seems that ~10,000 was the low point based on current methods. In order to say that those methods might have missed the real 2-person bottleneck event, I have asked you (or others) to propose how such an event might have taken place.
Unless I’ve missed it - and I might have - I have not seen you propose any mechanism for a precipitous drop to 2 followed by exponential population growth. I don’t see this as plausible. @Swamidass gave it a go earlier, but that showed the difficulties. It can’t reasonably be genetic isolation of a population, since this is happening in Africa/Eurasia, and there is no way to geographically isolate populations on that landmass (the only way to assure genetic isolation). So, it would have to be an event that (a) kills off all but 2, but then somehow also allows for exponential growth immediately thereafter.
That’s not biologically plausible. At least, not to me, nor to any biologist I’ve discussed it with (except for @Swamidass, perhaps). Perhaps you have a model in mind to explain it that I am missing?
In other words, if what you are proposing is not biologically plausible I don’t see a pressing need to address it.
Now, if I was writing AatG today, I would include a discussion of this conversation, and what we’ve learned from it, to be sure. What I would also do, however, is discuss why I don’t find the “sudden catastrophic bottleneck to 2 followed by explosive exponential growth” hypothesis to be compelling.
Thoughts?
… And now for something completely different:
Another thing that I have been meaning to ask for a long time in this conversation is this. Several years ago, you were widely quoted by the Discovery Institute and other ID sources as claiming that the identity of the human and chimpanzee genomes was around 70. It seems your original article on the subject is no longer online, but here’s how the DI quoted it at length:
Do you still think that humans and chimpanzees are around 70% identical at the DNA level? If so, why? If not, why not? Seeing as this is @glipsnort 's area of expertise, he might also be interested in your thoughts. I’ve been meaning to ask you this for months, and I keep forgetting to do so.
6 posts were merged into an existing topic: Discussion with Richard Buggs about chimp DNA
This claim is not substantiated by evidence. It requires an equivocation between Homo sapiens and “all our ancestors.” This is an example of the ecological fallacy.
The fact of the matter is we know that Homo sapiens dip down (backward time) to zero, so that obviously goes down below 10,000. Your heliocentric claim is transparently false.
You have missed it. That is a caricature of the argument and what is required for a genetic bottleneck. Someday we can press that argument, but its not worth it now.
More importantly, this is not related to your prior claim above, which is clearly not substantiated by evidence, and precisely false.
I confess to not having followed this discussion very closely. I thought around 500,000 years was the agreed limit – what are you basing the 700,000 years on? (Just curious.) Obviously, all of these numbers are somewhat mushy. If you accept the estimated time of 700,000 years for the sapiens/Neanderthal split, then that’s your limit, of course.
Not exactly my area; I was an author of the chimpanzee genome paper, but my contribution was in modeling selection, not in the sequence comparison. On the other hand, I am pretty familiar with the paper, and it’s safe to say that the quoted text is completely wrong. Similar claims have been repeatedly introduced into Wikipedia, where they have have had to be weeded out.
Short summary of the actual comparison:
2700 million base pairs (out of a total of roughly 3100 million bp) of the chimpanzee genome was sequenced well enough to be compared. That is the portion we can say something about. Of that 2700 million, 2400 million could be aligned to the human genome. This portion is the basis for the conclusion that 1.23% of sites in shared DNA differ by a single-base substitution, and that another ~1.5% was unique to each genome. (Based on these numbers the most reasonable single statement of overall similarity is that approximately 97.3% of the human genome is identical to the chimpanzee genome.)
The remaining 300 million base pairs of chimp DNA was sequenced but was not compared. 240 million bp were left out because they aligned to multiple places in the human genome. Much of this (I don’t know exactly how much) was the result of badly assembled chimp DNA, while some may represent genuine duplications in the human lineage. Another 90 million bp didn’t align to human at all; again, most of this was probably garbage of various kinds – badly assembled chimp DNA, parts of the human genome that hadn’t been assembled, etc.
No, we don’t know that. We know that there were once zero Homo sapiens, but that is not the same as saying that Hs “dipped down” to some specified bottleneck size, or to zero. The former is a statement about the characteristic of the population, while the latter is a statement about the population size. Two quite different statements.
I missed it too,
I know. Let’s grab a bear 
in Boston at the ASA meeting and hash it out. I’ll buy the first round for you =).
[
Silly @BradKramer adds a , obviously I meant a 
]
That is just an example of how we know the population genetics data does not tell us how many homo sapiens are around. It all comes down to how we define “homo sapiens”.
Regardless, this is all a red herring any ways (perhaps even intentionally), as there is no good reason to link “human” to Homo sapien. That is an example of eisegesis and concordism. “Human” in theology is not a scientific concept.
I try to avoid grabbing bears – the results are always unpredictable and often painful. (Also, there are surprisingly few bears in Boston.)
I’m not currently planning on going to the ASA meeting, other than the science panel, but I’m sure we can arrange something.
Other than the Bruins, that is.
You’re correct in your guess - the human / (Neanderthal - Denisovans common ancestor) split at ~ 700KYA. There’s also the fact that that Denisovans genome has some parts that seem to be around 1MY old, but that’s more up for debate.
I just don’t find the sudden bottleneck to two compelling either. For multiple reasons: 1. Hominins have always been pretty widespread so what kind of event can cause a severe bottleneck of two? What kind of natural disaster? Now I guess you could argue the event happened to a local population and that population dipped to two and then they outlived the other populations and didn’t reproduce with them. Which leads me to my second issue
2. If it happened to a local population what in the world could keep them isolated from the other populations? Like I said hominins moved around.
3. It seems the prior probability of a population dipping to two and not going extinct would be very low. And these two individuals would have to be male and female and at the right age to reproduce. A 40 year female and an infant aren’t going to do you much good.
4. I also have theological concerns
It’s an interesting idea but I don’t find it compelling at all.
I’m hoping to meet both of you!
Hi Dennis,
I think that you and @RichardBuggs might be working from different definitions of the problem.
The hypothesis under scrutiny is that all of humanity on the planet today is the genetic (not genealogical) offspring of a single couple. Your view is that this implies that 100% of our genome must be traced back to that couple. So the couple would have to be the exclusive genetic forebears of H Neanderthalis as well, because over 1% of the genome of non-African populations comes from Neanderthals. Since the Neanderthal/H Sapiens split was 700kya, that is the earliest possible date for the single couple.
On the other side, @RichardBuggs seems to believe that the claim of single couple sole genetic ancestry does not imply that 100% of humanity’s DNA must trace back to that couple. He would thus allow hybridization between humanity and non-humanity (Neanderthals, Denisovans), and logically the date could be earlier (500kya).
It seems logically incoherent to claim that humanity is solely descended from a single couple, and also to allow for hybridization with creatures that are not descended from that couple. I note that Hugh Ross stated about 10 years ago that the Bible predicted that there was no hybridization between H Sapiens and Neanderthals; the Bible claimed (in Ross’ view) that 100% of humanity’s genetic code must come from that single couple. So I would accept your definition of the claim, Dennis. (And Ross’ 10 years ago.)
Moreover, if anyone is willing to permit humanity to have less than 100% genetic descent from that couple, then the vastly more sensible solution is @Swamidass’ genealogical Adam and Eve hypothesis, which would easily put the couple in the timeframe of the capabilities we associate with humanity.
Pax Christi,
Chris Falter
@Swamidass (and @DennisVenema ):
Joshua, I think you have made a category error in your thinking here… and this is the post I just made back where your “…Against a Bottleneck of Two?” first appears. And you made it quite some time ago!
I, like @glipsnort, didn’t even notice you doing this so many months ago!
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Continuing the discussion from Heliocentric Certainty Against a Bottleneck of Two?:
This is the kind of distortion that I would have expected from a YEC, not from you.
You appear to be attempting to “divine” a dividing line between Homo Sapiens and NOT-Homo Sapiens… but this has nothing to do with a regression analysis of genetics back through the common ancestry!
Whether there is a “first” Homo Sapien in God’s eye rather than in the view of human operated sciences, (made through evolution rather than through special creation), the first “man” would still be part of a fairly large population!.. say 10,000 or more!
You need to straighten out your description of this key part of your operating scenario… because right now you are mixing apples with oranges…
Hi all, I have been a bit distracted from the bottleneck issue by the human-chimp genome similarity issue that @DennisVenema raised. This has now moved to another thread here: Human Chimp Genome Similarity
I will try to get back to the bottleneck issue soon!
Richard
Hi all, this paper, by some of my close colleagues and collaborators, came our yesterday in Nature Evology and Evolution “The ash dieback invasion of Europe was founded by two genetically divergent individuals”
https://www.nature.com/articles/s41559-018-0548-9
This is a portion of what the article discusses:
You aren’t trying to suggest that the 2.5 million haploid individuals have disappeared from the Earth, are you?
Hi Dennis,
Sorry to take a while to respond. You have quite distracted me by bringing up the human-chimp similarity issue, which is very interesting. I had been wanting to re-visit that issue for some time. But back to bottlenecks…
This is an “argument from personal incredulity” (to borrow a phrase from Richard Dawkins). I am interested that this now appears to be your strongest argument against a bottleneck. I suspect that many people will find argument this less compelling than the “certain” case from population genetics that you appear to make in Adam and the Genome.
As far as I can see, a step-by-step evolutionary pathway for a lineage passing through a bottleneck is clear, and you just have doubts about the selective forces that could drive it. As arguments from personal incredulity go, that is not a very strong one.
I am sorry, but I don’t think this is a complete summary of your claims in Adam and the Genome. You made very specific claims about what the literature was saying, and these have not stood up to scrutiny.
In addition, I think that most readers of Adam and the Genome pp45-65 would conclude that your major claim was that a bottleneck of two in the human lineage is almost impossible on the basis of analyses of current human genetic diversity.
But we have discussed these issues before, and anyone can read your book and make up their own mind, so I won’t belabour the point.
No, as we have discussed, methods applied to date suggest that effective population sizes have not dipped below several thousands, but they do not show that census population sizes have not dipped below that figure.
As I say, I think that most readers of Adam and the Genome pp45-65 would conclude that your major point was that a bottleneck of two in the human lineage over the last 18 million years is almost impossible on the basis of analyses of current human genetic diversity. Your new view is a significant departure from this point.
So have I! Thank you for coming to the table.
May we all be more and more like Chaucer’s Clerk: “And gladly wolde he lerne, and gladly teche.”
Good to hear that. It would be a very different chapter, to be sure.
You would do your readers a service if you wrote a blog to tell them now, as far as you are able, that present day genomic diversity in humans does not preclude a bottleneck in the human lineage between approx 700K and 7myr ago. I think you owe this to them, and to everyone who has taken the time to participate in this discussion.
This is certainly not @DennisVenema’s “strongest argument against a bottleneck.”
The strongest argument against a bottleneck, is that a bottleneck of a single mating pair would have left genetic traces well past 10,000 years ago.
And isn’t that pretty much the litmus test? You seem to indicate that if Dennis can’t prove there was never ever a bottleneck of a single mating pair … even further back than 300,000 or 400,000 years ago… then he must be grand-standing.
I would suggest that the grandstanding is going on from another vector… Dennis has convincingly demonstrated that there isn’t a trace of a bottleneck of a single mating pair for as far back as any convincing understanding of “humanity” can be thought to exist. 300,000 years should pretty much cover that, yes?
Since you have returned to this thread less than an hour ago, perhaps you could take a moment to answer my question from quite some time ago:
I’ve already agreed with this, and it’s been up there ^^ for weeks now. You’re welcome to publicize it as you wish. I no longer write in an official capacity for BioLogos, except by invitation from time to time. This means I’m just another commenter like you for the time being.
I beg to differ. It is not @DennisVenema’s personal incredulity you have to worry about, but the incredulity of a great deal of people. We have evidence of a number of hominin species existing between 1 My and 500 Kya. (Assuming that 500 Kya is still the threshold for detecting a bottleneck.) The speculation that all of them disappeared into a bottleneck of two breeding individuals has no evidence to support it, and you are not even willing to speculate how it might have occurred.
Moderators, can you please return the hours that I’ve wasted reading this thread?
Agreed. Provide a plausible mechanism for this event and there might be something to discuss. So far, I’ve seen nothing remotely plausible. I’m willing to entertain your ideas, @RichardBuggs - but you haven’t shared any.
In the words of Miracle Max, “It would take a miracle.”
Actually, while I do not see that we have come to any amazing conclusions, I think it has been educational both in the subtleties of how the data is interpreted, and how the discussion of ideas takes place in science. Thanks to all involved in contributing, as I have learned quite a bit (though still quite lacking in understanding it all)
Personal incredulity? Seriously…? It’s a valid request and if we are supposed to take an ancient bottleneck seriously then mechanisms need to be put forward. As IDer’s love to say, “show me the mechanism!”
It’s not even a matter of personal incredulity at all. As you’ve pointed out, it’s a matter of there being no evidence to support the claim, no proposed mechanism, and a far more efficient explanation for the available evidence. This isn’t a matter of personal incredulity, it’s a matter of preferring an explanation which is supported by the available data, and for which there is a demonstrable mechanism.
It must be remembered that the only motivation for this bottleneck theory is theological; it is not scientifically motivated. No outstanding evidence has been presented which can best be explained by proposing a bottleneck. A bottleneck does not provide a preferable explanation for the available evidence. A bottleneck is a solution looking for a problem.
Indeed.
Love it. I try to work Princess Bride quotes into my lectures wherever possible. Almost the whole movie is quotable lines.
Your turn to stump me on a pop culture reference, I guess. Lol. (Inside joke. Don’t ask.)
Oh, quite educational. The conclusion seemed straightforward, simply ruling out a 2-person bottleneck for as far back as the models allow (500 Kya). On how the discussion of ideas took place to arrive at this conclusion, it seemed to occur mostly via browbeating and chest thumping, and when the time came to interpret the data, Swamidass attempted to state it in terms that favored his genealogical thesis, and Buggs attempted to state it in terms that favored his bottleneck thesis. That in itself was educational, I suppose.
Regardless, I also thank those who contributed their time, energy, and thought to the discussion.
All the above is very helpful. I believe it wa Dr Buggs who wrote: “human genome is 84.4% the same as the chimpanzee genome [note added 23/4/18 to avoid disambiguate: i.e. this is our minimum lower bound]. Regarding the regions that are not one-to-one orthologs, I would explain that about a third of it (a little under 5% of the whole genome) appears to be duplicated.”
My question is does this include exons and introns, or just exons in the comparison ?
They continued that part of the discussion in a new thread:
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