Emergence of our species, Mitochondrial Eve and Y-Chromosomal Adam

Hi all,

I believe it is generally agreed that anatomically modern humans emerged in Africa around 200,000 years ago. When it comes to Mitochondrial Eve and Y-Chromosomal Adam I believe there’s some difference of opinion as to when these two individuals lived. In the Biologos and RTB book Old Earth or Evolutionary Creation Darrel Falk suggests current data gives a date of 165,000 years ago for M-Eve and 240,000 years ago for Y-Adam (p.183).

In the same book Fuz Rana and Hugh Ross seem to think that current data gives a converging date for the two individuals at 130,000 years ago. They also seem to think that these two individuals are the biblical Adam and Eve, even though Darrel Falk points out that M-Eve and Y-Adam only contribute a small segment of DNA to our genome. The other 99% comes from a whole range of ancestors who lived hundreds of thousands and even millions of years ago (p.195)!

Why do Rana and Ross think:
(a) the dates for these individuals converge around 130,000 years ago when it seems this isn’t at all what the data suggests?
(b) that these two individuals are the biblical pair, our sole progenitors, when it’s clear that (1) M-Eve and Y-Adam only contribute to a fraction of our genome, not the whole thing and (2) it’s clear we didn’t emerge 130,000 years but 200,000 years ago

I just can’t my head around their conclusions!

Mitochondrial Eve and Y-chromosomal Adam do not point to a genetic inheritance exclusively from individuals at all. It is true that there is a slightly higher probability that these would be during times of a genetic bottleneck of some kind. And the estimated dates do correspond to a proposed surviving remnant of modern homo sapiens in Southern Africa which is the source of migrations to the rest of the world. But even such a remnant population has been shown not to be the exclusive source of the genetic pool of modern humans which include a contribution from Neanderthals in the north and Denisovans in asia. And furthermore the total population estimates of any such bottleneck (including those other contributions) is at least around 10,000 people.

The idea that the mitochondrial Eve and Y-chromosomal Adam point to a couple or family as the sole genetic progenitors of humanity is an outright lie. When you consider the simple fact of the geometric expansion of any ancestral tree, it is logically inevitable that they have to start overlapping a lot at some point in the past and thus all of humanity shares numerous common ancestors (people from whom everyone has inherited some genetic material). But these exclusively male and female inheritances in mitochondrial RNA and the Y chromosome do not branch but go back in a singular line excluding the vast majority of our ancestors. The logical result is that there would be one (or more) female common ancestors from whom we would inherit the same mitochondrial RNA which survived in modern humans and one (or more) male common ancestors from whom we would inherit the same Y-chromosomal DNA which survived in modern humans. That is all this stuff means.

Thanks for the reply Mitchell, much appreciated. I understand who M-Eve and Y-Adam are from a genetic POV and the minimum human population. My confusion is over why the RTB guys would think that these two individuals are sole progenitors when obviously they are not. They’re obviously clever guys, and I wouldn’t think they were lying, but how can they seem to misunderstand something which seems fairly straightforward, even to an interested layperson such as myself…? Additionally, why they think the dates on these individuals converge at 130,000ya and therefore that this is the date humans originated, even though we know we emerged around 200,000ya.

I just can’t see how they get to their conclusions.

You can come up with just about any conclusions you want if you adopt the premises which lead to that conclusion. Such premises certainly are not justified by the scientific research, but they may feel these premises are justified by the fact that they support the conclusion which agrees with their interpretation of the Bible. Frankly we often see religious people and those in various sales schemes jumping on whatever scientific facts sound even a little bit like what they are selling. After all, the rhetoric of salesmanship is far more deeply rooted in the operation of human civilization than science, and it is easy to conclude that it is this rather than science which makes the (human) world “go round.” Thus perhaps people are more commonly wired to go with that methodology of knowledge rather than the far more restrictive logic of scientific inquiry which, after all, tends to get a bit more complicated than most feel able to follow.

As for the thinking of the RTB guys you have to ask them. I have been told there is some connection with this site but I don’t really understand the nature of that connection because their beliefs hardly reflect what this site is all about.

These are lines drawn in the sand frankly and totally artificial human constructs in the largely arbitrary categories used in human language. Who is to say where the line is in a constantly evolving species even IF we could know with absolute certainly what exactly happened.

Since I strongly disapprove of genetic definitions of humanity, I see no reason to look for the Adam and Eve of Genesis (for I do take an historical view, even if I see the story as filled with symbolism) in such a remote period of the past, but instead something more like 10,000 years ago closer to the advent of human civilization. The more you push it back like they have done the more insigificant the connection with God becomes in the development of human civilization. Frankly this jumping on genetics is another way in which their efforts to justify their beliefs have diverted them the original ideas to create a new religion which I think is a bit twisted and bizarre.

Since most people in the BioLogos network don’t share this perspective, I don’t know how helpful most people will be in explaining it.

Maybe @SWilling who has some affiliation with RTB could point us to an article or something.

Hi @Christy, thanks.

If it helps anyone, I’m getting my information from the book I mentioned above, joint published by Biologos and RTB. The claims made by RTB appear mostly in chapter 10 where RTB’s Fuz Rana is debating Biologos’ Darrel Falk.

@mitchellmckain, thanks again for the reply. I totally agree with this sentence of yours:

You can come up with just about any conclusions you want if you adopt the premises which lead to that conclusion.

I’d just ask them. I’ve wondered the same thing, and like yourself, I can’t decide what’s going on.

Of course, they also deny human common ancestry despite mountains of evidence in its favour, so, yeah.

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But we’re the only ones with a discussion forum :wink:

Unless you count the peaceful folks.

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I’m glad I’m not the only one!

What you’ll see is that Rana will say that mito Eve and Y-Adam are “consistent” with them being sole genetic progenitors. I don’t think I’ve ever seen him say that the evidence supports that they are. What you’ll see is Rana try to poke holes and cast doubt on population genetics models - but the ones he uses (the mouflon sheep one seems to be his favourite) are so simplistic that it’s really no surprise that they don’t hew exactly to the known population demographics.

The mouflon sheep one, for example, is a very simple case of assuming neutrality and expecting a loss of heterozygosity as a result. It looks like in that population that heterozygosity is an advantage for some loci, and linkage disequilibrium is maintaining some alleles at other loci. Not at all surprising. So, the “model” based on unrealistic, simplistic assumptions says that maybe the population was founded by a handful of sheep (like 4 or 5) rather than a single pair.

If you think that kind of result actually means anything when looking at the models for human population dynamics I’ve got a bridge I can sell you, cheap. But it sure sounds good to people who don’t know anything about population genetics.

Does Rana understand what he is doing? I don’t know what’s going on, so I can only go with the outward phenotype.

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True that neither RTB or any of the various YEC orgs allow for comments on their websites. I’ve always appreciated that BioLogos does this, and I’m thankful for all of our moderators who are a big part of making this work.

… and surely some of the onlookers must realize that if you’re willing to have any and all critique your position, it must be able to withstand that critique.

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I haven’t heard anything on this subject in quite a while, and the hostile remarks above make me reluctant to step in.

“Mitochondrial Eve” was not a term coined by RTB, but researchers in the field and picked up by the media. It began in the mid 1980’s when Allen Wilson at Berkeley concluded that, indeed, all living humans had a shared common female ancestor. The y-chromosomal Adam should actually be y-chromosomal Noah if, indeed, there were a later extinction event survived only by Noah and his sons.

RTB does allow comments on their blog posts. They do not run a discussion forum and I certainly think it is something they should consider. Since it relies completely on donor support, it doesn’t have access to the same degree of funding as BioLogos but a forum shouldn’t cost much to run.

Describing their position as “an outright lie” is indefensible. It prejudges intent to deceive, and the RTB scholars are as sincere and humble as any I’ve ever encountered.

I have an Evangelical friend who is a molecular geneticist at UAB and I look forward to talking this over with him next time I see him. My opinions are not set in stone but neither are the current implications of paleogenetics.

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What was described as an outright lie was “the idea that the mitochondrial Eve and Y-chromosomal Adam point to a couple or family as the sole genetic progenitors of humanity

Is that what RTB actually claims though? I think that is what the OP is trying to sort out.

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I agree that it’s not appropriate to judge the motivations of people, so I too would not use a term like “lie”. But from the context it seems to me that this was used as an expression of how far off the rails it would be to use the idea of Mito Eve and Y-Adam to claim sole genetic progenitorship. And that is certainly the case - it is very far off the rails, indeed.

Steve @SWilling , do you think Fuz would be willing to drop in here and discuss this? Perhaps you could invite him.

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There was never any doubt that all living humans shared a common female ancestor. The “Mitochondrial Eve” work put a name on the most recent common ancestor by matrilineal descent, and gave evidence about when and where she lived.

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It is exactly what they claim in the book (published 2017). In fact, perhaps it’s helpful for everyone to see for themselves from these excerpts from Googlebooks:

Rana (result from p.188)

Ross’ conclusion ( result from page 217)

There’s a clearer Rana quote from p.190 but it’s not available on the googlebooks preview. Hopefully those two above suffice.

In a private group post of August 2018, Fuz was standing by this 2017 article:

Conservation Biology Studies Elicit Doubts about the First Human Population Size

where he expresses reasons for skepticism but does not dismiss it. I think a measured skepticism is always reasonable in the scientific realm, having seen my own field (medicine) run off the rails many times and knowing full well it will happen again. One can be consistently and reasonably skeptical without descending into YEC lunacy. Fuz may overstate the significance of implications; I don’t find the alternative position of genealogical Adam and Eve, as opposed to biological, all that threatening to Christian doctrine.

I’ll drop a note and let him know about this conversation.

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It is threatening to common sense, though.

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@SWilling

@Jay313 has done some academic research that is not yet published critiquing G.A. I don’t think the above post was intended as a cheap shot, or was directed at your personal beliefs.

But Jay, you should elaborate, not just be snarky.

No, I didn’t think @SWilling was saying that he personally believed it. It sounded to me like he simply was listing it as an option.

Do I have to elaborate? Can’t I just swallow the snark and pretend it never happened?