Mitochondrial Barcodes: An Adam-Eve Bottleneck 200,000 Years Ago?

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(S. Joshua Swamidass) #1

One of the most trafficked pages on the forum is this one: Did All Species Arise about 200,000 Years Ago?. A very poorly done study on mitochondrial barcodes led to many fallacious claims. We were the first site to debunk it, and so came to us much web traffic.

Ironically, we have also show three ways that an Adam and Eve could make sense with the evidence. (Three Stories on Adam), includeing (1) sole- genetic progenitorship (Heliocentric Certainty Against a Bottleneck of Two?) , (2) genetic -interbreeding progenitorship (discussion) and (3) the Genealogical Adam (http://peacefulscience.org/genealogical-rapprochement/).

With so many options available, it is frustrating I had to rebut this study here:

@Joel_Duff also picks this up and writes his own article to explain some errors heree (Joel Duff: Animal Species Arising Same Time as Humans?).

Yet, somehow, Michael Guillen, a Celebrity Physics PhD, missed the correction, and is taken in. He decided to write an article about how this confirms the biblical story.

That said, Stoeckle and Thaler’s study does line up with the Bible in at least two notable ways. First, it affirms that we and our fellow creatures on Earth arose from a recent and profound creation event, orchestrated by some unknown mechanism. And second, the DNA bar codes reveal that species are quantized. Instead of there being a continuum of animal varieties, as one might expect from millions of years of gradual evolution, creatures fall into very distinct, widely separated populations – what the Bible describes as “kinds,” from the Hebrew word min.

I am a Christian too, but this is not what the study does. I have a feeling the original article is going to pass around the internet for a while. Just one poorly written article, and it is surprising how much negative impact it can have on public understanding. Hopefully Dr. Guillen will join us here to discuss.

Another related news report made the same mistake, just appeared in my inbox. This one actually interviews the researchers, who are at least rying to clean up the mess they now know they have created…

The study has been misunderstood by some religious parties who thought it meant that we all came into being in some seminal Big Bang-typed event 100,000 ago, but this isn’t what the findings actually suggest.

It also does not mean many of the things they claim it did:

The ‘mitochondrial DNA’ examined in the research is that which mothers pass down from generation to generation and it showed the ‘absence of human exceptionalism.’


Gauger on Mitochondria Barcodes and Adam and Eve
(Timothy Horton) #2

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(Joel Duff) #3

yes, a new round of popular press articles has cropped up about this now nearly year-old research paper. I’m not sure why it suddenly is making news again but it feels like someone must be coordinating this response. Aside from the Foxnews click bait article there is one that is just as bad in the Daily Mail that appeared within 24 hours of the Fox one that includes this line:

Scientists surveyed the genetic ‘bar codes’ of five million animals - including humans - from 100,000 different species and deduced that we sprang from a single pair of adults after a catastrophic event almost wiped out the human race.

This is certainly nothing close to what the authors have said. They don’t say or even imply 2 individuals. I’m not as negative about the original piece as i was when I first saw it. Yes, I would have worded their conclusions differently - or at least more carefully knowing how it might be taken by the anti-evolution crowd - but I don’t have a big problem with the data or analysis. The results are what they are and need to accounted for. That’s just how science works and there is more being done that has been stimulated by this paper.

BTW, Michael Gillen’s profile says he is working on a book about science and the bible to be published by Harpers. Given this article and others he has written I’m not very confident that this book will be very helpful.


(John Harshman) #4

Could somebody just cite the original study?


(S. Joshua Swamidass) #5

(John Harshman) #6

Still not published?


(Timothy Horton) #7

The paper was published in the journal Human Evolution in May 2018. Basically the authors looked at genomic data for a large number of species and observed most had their own version of “Mitochondrial Eve”, the last common maternal ancestor (LCMA) to all the species members alive today, occur in the range of 100K-200K years ago. This does not mean that individual ancestor was the only female alive at the time, just the one all living species members can trace their maternal ancestry back too. It also doesn’t mean the species started at that time.

As Dr. Swamidass has already pointed out the authors’ made the dubious claims 1) the LCMA indicates the start of the species, a view not accepted by most in biology and 2) the the data shows a bottleneck down to a single breeding pair in that time frame. For humans this second claim is almost certainly false as the accepted time for Y-chromosome Adam and mtEve are different by tens of thousands of years.


(James McKay) #8

I think the best response here is this:

image


(Joel Duff) #9

Yep, pretty much sums it up.


(John Harshman) #10

That sums up a lot of situations, but here it seems the authors themselves have gone directly from “A is correlated with B” to “What you don’t know about A can kill you”.


(S. Joshua Swamidass) #11

Honestly, from reading that last article, I’m not sure if the authors are really struggling to communicate with the public, or if they are really that confused about their results.


(Joel Duff) #12

I don’t believe these (Mail article?) are new statements by the authors. This is stock stuff that has been said the last 8 months and your quotes are from whoever authored the article not the authors as I thought you were implying.
This is a complex topic with a convoluted history so I’m just trying to keep things as clear as possible.


(S. Joshua Swamidass) #13

(Ashwin S) #14

I read the paper. They seem to be claiming that the current population of human beings in existence are derrived from a bottleneck 100k to 200k years ago.
They also claim the same for current populations of 90% of all the animals species.
I.e, the uniformity found in extant species can be explained by a bottleneck that their ancestors went through 100k to 200k years ago.
(or atleast they claim the mitochondrial Bracode evidence points to such a conclusion).
@swamidass, i am not sure this is a case of misreporting.
If their study is wrong, i am sure someone will publish a rebuttal now that it has become famous.


(Matthew Pevarnik) #15

Looking at a 648 bp region.

Given that no studies have found positive evidence for a bottleneck so recent I’m not sure what actually needs to be done (with a nice summary of the tip of the iceberg regarding evidence given by @swamidass):


(Ashwin S) #16

I am not sure what you mean by positive evidence.
The current paper proposes some evidence as supporting a bottleneck at more than 100Kya.
I wasn’t commenting on whether their claim is valid or not. Only that such a claim is made/argued for in the paper. (as opposed to it being a case of misreporting).

Would it bother you if it turns out that there was such a bottleneck?


(The Questioner?) #17

Can anyone explain how evidence that points out a potential bottleneck is dismissed, yet someome digs up a bone chip of an ape like hominid and every scientist falls all over themselves to prove that it is a major discovery?

The data says what your theory says it is… that which supports a hypothesis is accepted, and data which proves the opposite is dismised as a mistake and minimized.

Science has become a religion for the faithful, intellictual study given a pass because it is done by “smart people” who know more …so it is accepted. Things accepted and primted in textbooks have to be true or else (like the Catholic Church … which held on to Aristotelian theorys despite evidence that these theories were inaccurate) the whole of Science will be shaken to its core.

This seems like a fallacy of argument to dismiss this without giving it a fair and scientific evaluation.

Freedom is slavery, ignorance is strength … 1984 George Orwell.


Introducing Matt Mirecal
(Steve Schaffner) #18

The problem is that their data do not in fact point to that conclusion. At most, their data suggest that for a wide range of animal species, the effective population size times the generation length is roughly constant. This is not a terribly surprising conclusion (smaller critters tend to have larger population size and shorter lifespans), but since it’s based on a single small coding region, and a mitochondrial one at that, it would rest on very thin evidence.

Maybe, maybe not. Most researchers are probably still unaware of the paper, and even if they do know about, rebutting a dumb study in a lower tier journal isn’t a big career-booster, even if the dumbness has been repeated on Fox News.


(Steve Schaffner) #19

Sure. This study is being dismissed because it is wrong – unambiguously, thoroughly wrong. Its conclusions do not follow from the data they present. Scientific errors should be dismissed. As for the other cases you contrast it with – what bone chip do you have in mind?


(S. Joshua Swamidass) #20

13 posts were split to a new topic: Ashwin Argues Against Scientific Expertise