Vort

Question about the "mysterious extinction even that preceded Adam and Eve"

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I think maybe this should have its own thread rather than hijack this original thread. Let me ask it here. The question pertains to the following article:

https://www.foxnews.com/opinion/did-a-mysterious-extinction-event-precede-adam-and-eve

I have been struggling for over a month to understand why this article merited a news slot. At the risk of exposing my own ignorance, isn't this dead obvious? Wouldn't any thoughtful, intelligent atheist conclude that all members of every bisexual species must eventually have very few, perhaps only one, matrilineal species ancestor and one patrilineal species ancestor? Or is there some subtlety I'm missing? Here is a hopefully brief four-part explanation of what I mean.

PART ONE: YOUR ANCESTRY

How many of YOU are there? That would be one. (If you think otherwise, please seek help.) And how many PARENTS do you have? Two: One man and one woman. How many GRANDPARENTS? Four: Two male and two female. How many GREAT-GRANDPARENTS? Eight: Four men and four women. How many N-GREAT-GRANDPARENTS? 2N+2, where 2N+1 are male and 2N+1 are female.

So as you peruse your ancestral line, watching the number of ancestors double in each generation, then you have over a thousand ancestors just ten generations back, about the time of the founding of the US. You have over a million ancestors just twenty generations back, around the time of some of the early English colonies in the New World. Go back just thirty generations, which is around the beginning of the Renaissance, and you have a over BILLION ancestors–more than the human population of the entire planet at the time! Go back ten more generations, into what we call the high middle ages, and you have OVER ONE TRILLION ANCESTORS, far more than ALL THE HUMANS WHO HAVE EVER LIVED!

And that's just going back to about 1000 AD. Hey, the math is straightforward.

But not really. Obviously, something's going on here. And that something is [drum roll] cousin marriages.

If your parents were first cousins–and that would explain a lot, hey, I'm just saying, don't shoot the messenger–then you would not have eight great-grandparents. You would only have SIX great-grandparents, because your parents would share a set of grandparents (since they're first cousins). If your parents were Nth cousins, then you would have one set fewer of Nth-great-grandparents.

Guess what? Cousin marriages are rife throughout human history. (The fact is, sibling marriages are much more common throughout history than we like to suppose, but let's just not think about that for the moment. Yeah, you're welcome. Merry Christmas–or is that marry Christmas? Oops. Shame on me.) In fact, cousin marriages are common in many areas of the world even today. If you want to stretch the point just a tiny bit, cousin marriages are absolutely unavoidable, unless you want to marry a leopard, a frog, or a tulip.

Obviously, after not very many generations, you start seeing common ancestors from various lines, meaning those various intermarrying lines were cousin marriages (albeit probably fourth or fifth or eight cousin marriages).

PART TWO: PATERNAL AND MATERNAL LINES

Let's suppose for a moment that we have an infinite number of non-intermarrying ancestors. If we go back ten generations, then we have 1024 (210) ancestors, 512 men and 512 women. That will include your mother's mothers' father's mother's mother's father's mother's father's father's father, for example. But look only on the maternal line–that is, just the mother's mother's mother's (etc.) mother. How many maternal-line-only mothers do you have at the tenth generation? You have EXACTLY ONE.

How many maternal-line-only mothers do you have at the sixth generation? One.

How many at the ten thousandth generation? One.

Note that the same is true for the paternal-only line. How many father's father's father's (etc.) fathers do you have at N generations? THE ANSWER IS ONE, FOR ANY NUMBER N.

So in our theoretical non-intermarrying ancestor line, if a billion unrelated people trace their genealogy back, let's say, one hundred generations (roughly 2000-2500 years), they will have a billion separate paternal-line-only fathers and a billion separate maternal-line-only mothers.

Now clearly, in the real world, this is nonsense. All 360 million (or however many there are) Americans share a much smaller group of 100th-generation paternal-line-only fathers and maternal-line-only mothers. Realistically, this group will be fewer than a million or so people, probably no more than a few tens of thousand (or even fewer).

So while our collective ancestry embraces most of those who have lived before, our maternal-line-only or paternal-line-only ancestors are far, far fewer in number.

PART THREE: MATERNAL- AND PATERNAL-ONLY ANCESTRAL LINES DIE OUT

My wife's father was one of seven children, but was an only son. He had three daughters, but no sons. Today, he has seventeen living descendants: three daughters, six granddaughters, seven grandsons, and one (soon to be two!) great-grandchild. But though he has grandsons, none of them carry his Y chromosome. My four sons obviously carry my Y chromosome, which comes from MY father, not my wife's father. So while my father-in-law is well-represented by his descendants, and we may look forward to his posterity continuing as long as time continues, his paternal Y-chromosome descendancy is finished. His Y chromosome no longer exists on this earth. With its end, the line of his father's (my wife's grandfather's) Y chromosome is also dead, since he was his father's only son. I don't remember if there were other male descendents another generation back–I think there were not–but in any case, you can trace back along that line and find out that the Y chromosome inheritance from a certain generation onward is gone.

This is not a rare thing. On the contrary, it's extremely common. There are many, many grandfathers in our ancestry. There are many fewer grandfathers in our direct paternal line. Ultimately, there can only be one grandfather whose primeval Y chromosome we (men) all share, each of us with our own mutated version of it. We inherited it strictly through the line of our fathers; maternal grandfathers in any degree don't contribute to this.

This same reasoning holds true for the maternal line. Since our mitochondrial DNA is inherited ONLY from our mothers, it stands to reason that many women are mothers to us in our ancestral line, but only one line brings us our mitochondria. My wife and I have one daughter. Perhaps she will have twelve daughters of her own, each of whom will go on to birth many other daughters. But if our daughter has no girls of her own, or if her daughters do not have any daughters, at some point my wife's (and my daughter's) mitochondrial line will die out. My wife's sisters sisters, who share basically the same mitochondria, each have more than one daughter, so perhaps they have better odds of continuing that line. But fifty generations from now, a great many maternal mitochondrial DNA lines will have died out, and only a relatively few lines will survive.

PART FOUR: THE POINT

The article marvels that genetic analysis shows that we have a common mother ("Eve") that gave rise to our mitochondrial DNA and a common father ("Adam") who was our first Y-chromosome parent.

This is news?

OF COURSE there is an earliest genetic "Eve". At some point, our maternal ancestry will collapse to a single individual. Similarly, at some point our paternal ancestry will collapse to a single Y-chromosome ancestor.

So, brave souls who have actually read this far, I ask again: Why is this a newsworthy article?

Edited by Vort

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I'm not sure if it is newsworthy.  But if we believe in the evolutionary beginnings of humanity, we do NOT have a single pair of human ancestors.  By the laws of probability, humanity would have many.  

However, prior to the rise of homo sapiens sapiens, the original ancestor must be that first single celled organism.

A single asexual microbe.

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5 minutes ago, Carborendum said:

But if we believe in the evolutionary beginnings of humanity, we do NOT have a single pair of human ancestors.  By the laws of probability, humanity would have many.  

Sure, we would have many ancestors. But we would have a very limited number, probably exactly one, of each of our Y-chromosome fathers and our mitochondrial DNA mothers. Again, that's a rather obvious statistical probability. You simply can't have a large number of ancestral mitochondrial DNA mothers and Y-chromosome fathers survive in a limited population. Probabilistically, that's vastly unlikely, even if we don't consider e.g. wars where most or all of the men of a region are wiped out.

EDIT: Let me point out what I thought was apparent, but maybe isn't. The article doesn't claim that humanity has "a single pair of human ancestors" in the sense that all humans descended from only a single pair of people, with no other genetic inheritance involved. Rather, it references statistical genetic studies that suggest that all human mitochondrial DNA converges on (i.e. originated from) a single individual woman, called "Chromosomal Eve" in the popular press, who lived on the order of 100,000-150,000 years ago. Such studies also indicate the equivalent "Chromosomal Adam" as the ultimate ancestor of all living humans' Y chromosomes, and who lived somewhat longer ago than "Chromosomal Eve", perhaps 200,000 to 300,000 years ago. So they weren't a couple; in fact, "Chromosomal Eve" may very likely have been a 1,000-generations-later descendent of "Chromosomal Adam".

Edited by Vort

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When I get to a better interface than my cell phone, I'll explain.  But, no.  Under the evolutionary paradigm, we MAY have a single human father or a single human mother.  But the likelihood of a single mother AND single father is probabilistically near impossible.

And, having read the article from Fox, I understand the reason they call it news.

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17 minutes ago, Carborendum said:

When I get to a better interface than my cell phone, I'll explain.  But, no.  Under the evolutionary paradigm, we MAY have a single human father or a single human mother.  But the likelihood of a single mother AND single father is probabilistically near impossible.

Rather than respond to what seems an obvious error in interpretation, I'll instead wait for your reply.

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At the risk of sounding obtuse, i am pretty sure news-worthiness is not a criteria used in selection of content to display on most news sites.  

The articles that lead to the most clicks right now and in the future get put up.  

And i could be misunderstanding, but does anyone's mtDNA or yDNA have a time to live of more than 1?  Maybe, if you're really lucky, your child's mt/Y DNA is 100% like yours.  But most likely, it is 100% less a handful of mutations.  And if you don't have a male/female child, go a generation or two back, reversing those couple of mutations a couple times, and there is someone with your same mt/y DNA.  Occasionally, you had a very successful combination of mutations, which were able to perpetuate - and those are the haplogroups.  

And i guess the problem with tracing anything back, is that you've got to decide where to stop natural processes and call in that which cannot be explained.  Most Christians regress to back to mt-MRCA and call her Eve and to Y-MRCA and call him Adam before calling it a day.  And scientists take that a lot further back - but eventually dead-end themselves, too.  

Or such is my understanding at least.  

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PREFACE:

While I'm assuming that we're talking about the appearance of modern man (homo sapiens sapiens -- based on the dating from the aforementioned Fox news piece) from our nearest relative is the defining line we're talking about, the argument I'm about to make will equally apply to the evolution from species to species as well as subspecies to subspecies. The logic is the same.

STAVE 1 TERMS:

Forgive me if I'm mixing up some terms because back when I was taught about evolution (I went to school during the pre-Cambrian period) they used slightly different names than what they are using today. 

Modern man is known as "homo sapiens sapiens", a subspecies of homo sapiens.  We used to think that the nearest relative was homo sapiens neanderthalensis.  But they've discovered a newer subspecies: homo sapiens idaltu.  While we differ from Neanderthals by approximately 202 nucleotides, the idaltu are even closer.  I was unable to find how many nucleotides difference we have from them.  But I don't think it would be too far of a stretch to say we differ by around 100 nucleotides.

So, the origin of our species would be the first man or woman with the DNA of modern man.

 

STAVE 2 EVOLUTION IS GRADUAL:

It has been common to believe that evolution from one species to another entailed a major mutation that all-of-a sudden caused over 1000 nucleotides to change in a single generation.  This is inaccurate.  The way it works is that with each successive generation, only a few nucleotides differ.  Gradually, some combinations of nucleotides are selected for (natural selection).  Over the course of MANY generations, we'll eventually see that 100 nucleotide difference after MANY selection events (both major and minor).  

But is it a homo sapiens sapiens when they have 100 nucleotides difference from the utaldi?  How about 98?  90?  It is interesting to note that while the 202 nucleotide differences from Neanderthals is an average, the modern races vary in similarities with both the Neanderthals and the denisovans (predecessors to the Neanderthals).  It was found that Ethnic Tibetans actually shared many nucleotides with denisovans.  Thus they had traits that helped them survive the cold environs of Tibet.  Europeans tend to have about 3% of Neanderthal DNA.  So, clearly, the line is not so clear.  We blend smoothly into the other.

 

STAVE 3 THE FIRST HUMAN:

I don't know what standard the anthropologists used for their determination of when y-chromosomal Adam showed up.  But let us assume that the line was drawn at 20 nucleotides different from that of the average modern man.  And since the article said so, let us assume that the first being to cross that line was a male of the species.

This would mean that while he differed from modern man by only 20 nucleotides, his parents and those around him may have varied by 21 to 30 nucleotides (as an example).  So, his parents were not homo sapiens sapiens.  They were utaldi.  But he was close enough to utaldi that he lived among them without any major conflict.

So, whom did he mate with?  Most likely an utaldi female -- or possibly multiple females.  While none of these females were mitochondrial Eve (because they did not meet the 20 chromosome limit, they did mother "Adam's" children.

 

STAVE 4 ADAM'S OFFSPRING:

Let us assume for discussion purposes that Adam had 20 children from several females.  Let us also assume for discussion that 10 of them were sapiens, 10 were utaldi.  Of the 10 sapiens, 5 were male, 5 were female.

While Adam's Y-chromosome would be carried by all five male offspring, his X-chromosome was also carried by his 5 female offspring.  So, we can certainly say that the eldest female is the "first" human female.  But to think ALL humanity came from that single female would make no sense.

We have five different females to begin with.  And we have five males that could take mates from the utaldi and each in turn could produce male and female offspring that did NOT have the same X-chromosomes of their sisters.

Further, there is another quirk of X-chromosomes.  A woman gets her X-chromosomes from BOTH parents.  Which X-chromosome does she give to her daughter?  50/50.  So, how can there really be a single mitochondrial Eve of the human species under the evolutionary paradigm?  Basically, Adam could himself be responsible for the X-chromosome found in most females today.

Remember that this assumes that there was only ONE male who crossed that line within a few generations.  But if other groups or individuals were at around 22 or 23 nucleotides, it is quite possible that there were several others (male and female) that crossed that 20 line as well.

Therefore, there really wouldn't be a single man and single woman who created the human race.

The only way for it to be true (the way the article states) is if NONE of the female offspring for MANY generations crossed that 20 chromosome line.  And that would only be true if the necessary nucleotides were carried on the y-chromosome.  Therefore, only the males were sapiens for that many generations.

The reason I say this is probabilistically impossible is that when entire groups of the most advanced utaldi congregated, the chances of additional individuals crossing the line of just a couple nucleotides is pretty high.  That's what meiosis does.

 

STAVE 5 WHY IS IT NEWS?

What the article seems to be pointing to is a near extinction event. There were many sapiens all around.  But during the ice age, most became extinct.  In fact, all the utaldi died off.  Some neanderthals survived.  But they departed this earth some time later.

During that extinction event it is believed that the entire human race was reduced down to a few hundred survivors.  And if it was a clan, it is quite possible that those few hundred were the descendants of a single female.  If that's the case, it is news indeed.

 

STAVE 6 CONCLUSION:

I understand that my model is greatly simplified.  But I believe my logic is sound.

How that same X-chromosome survived through all these millennia is beyond me.  I don't know enough about gene mutation or even meiosis to be able to figure that out.

Edited by Guest

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10 hours ago, Vort said:

Before doing an in-depth response, let me observe that the X chromosome was never under discussion.

And I'll point out that the previous question was "why is this news".  So consider how my post answers that question.  The thrust of my argument was that due to randomness, the idea that only a single man or single woman had their patrilineal and matrilineal genes survive throughout all of human history would be near impossible.

Thus to find a single ancestor to be the fact, boggles the mind.

My understanding of the "matrilineal ancestor" is that the x chromosome is what would define "mitochondrial Eve".  Or at least that would be the primary method of determining who she was.  I'm sure that is a gross simplification, but regardless of the details, the reason it is "news" still remains.  And x-chromosome inheritance or not, the likelihood of a single common matrilineal ancestor actually being the reality is nearly zero.

My primary premise being that if there was a gene pool already sufficiently close to modern human that it would generate the first human male, then within that same generation or the few successive generations of utaldi, other humans would also spontaneously form as well.  Thus parallel lines of humanity form from a similar gene pool.  And I see no reason why they need be from the same familial stock.  In fact, the randomness required would be aided, not hampered, by different genes.

Thus with parallel lines, the idea that a single line overtook all the others seems to me to be a rather slim probability.

Edited by Guest

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2 hours ago, Carborendum said:

And I'll point out that the previous question was "why is this news".  So consider how my post answers that question.  The thrust of my argument was that due to randomness, the idea that only a single man or single woman had their patrilineal and matrilineal genes survive throughout all of human history would be near impossible.

Thus to find a single ancestor to be the fact, boggles the mind.

My understanding of the "matrilineal ancestor" is that the x chromosome is what would define "mitochondrial Eve".  Or at least that would be the primary method of determining who she was.  I'm sure that is a gross simplification, but regardless of the details, the reason it is "news" still remains.  And x-chromosome inheritance or not, the likelihood of a single common matrilineal ancestor actually being the reality is nearly zero.

My primary premise being that if there was a gene pool already sufficiently close to modern human that it would generate the first human male, then within that same generation or the few successive generations of utaldi, other humans would also spontaneously form as well.  Thus parallel lines of humanity form from a similar gene pool.  And I see no reason why they need be from the same familial stock.  In fact, the randomness required would be aided, not hampered, by different genes.

Thus with parallel lines, the idea that a single line overtook all the others seems to me to be a rather slim probability.

You might be saying this already, but i don't believe that mtDNA and the X Chromosome are really related.  mtDNA exists outside the nucleus of a cell.  For females, X chromosomes come from each parent, recombine, and then one of them is silenced.  And in males, comes from their mother (where recombination did occur) - so not an unbroken line.

At least this holds generally true unless you start talking about the various sex chromosome aneuploidies like Turners or Klinefelters.  

Though some recombination (or perhaps more accurately, translocation), between X and Y in males is not unheard of (example XX male, where SRY gene translocates from Y to X, and sets in motion the cascade of biological processes that result in male physical characteristics).  

Edited by lostinwater

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Wow - there is so much in this thread that I am not sure that I understand where anyone is going.  Below are some questions:

1. What impact does same sex relationships have on the gene pool?  Especially long term; if such relationships become increasingly more popular? 

2. Could same sex relationships trigger an extinction event or a bottleneck?  Is the answer to this question obvious?

3. Which are better for the gene pool - Inter-racial marriages or strict racial marriages - or some combination?

4. What is the effect of parental health on the gene pool?

5. What is the effect of fidelity and infidelity (or morals in general) on the gene pool?

6. Is selective breeding good or bad for the gene pool?

and what I consider the biggest question of all = What will be the long term affect of genetic engineering?

 

The Traveler

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4 hours ago, Carborendum said:

The thrust of my argument was that due to randomness, the idea that only a single man or single woman had their patrilineal and matrilineal genes survive throughout all of human history would be near impossible.

On the contrary, it's inevitable, unless by "survive" you mean "survive unmutated".

4 hours ago, Carborendum said:

Thus to find a single ancestor to be the fact, boggles the mind.

Not sure I follow why this might be so mind-boggling.

4 hours ago, Carborendum said:

My understanding of the "matrilineal ancestor" is that the x chromosome is what would define "mitochondrial Eve".

Not at all. Mitochondrial DNA (mDNA) is completely separate from chromosomal nuclear DNA. They are utterly different things.

A man passes on his Y (male sex) chromosome to his sons almost completely intact, except for some very tiny sections involved in meiotic swapping, and of course possible mutation. Thus, it is possible to determine a man's patrilineal descent simply by sequencing his Y chromosome. But a woman receives both parents' X sex chromosomes*, and when she passes an X sex chromosome onto a son or daughter, it is a composite of both parents' X sex chromosomes. So you can't use a woman's X chromosome to determine ancestry the way you use a man's Y chromosome.

But mitochondria are a different story. Mitochondria are shaped and sized very much like bacteria, and they have their own bacteria-like DNA—not chromosomal like nuclear DNA, but circular, like bacteria have. The mDNA sequence is very tiny, but distinctive. The important part is that it's not involved with the nuclear DNA, but is completely separate. So you don't inherit your father's mitochondria or mitochondrial DNA; that comes strictly through the mother. Whatever mitochondria are present in the ovum, that's the mitochondria the child ends up with. And since Mama provides the ovum, she also provides the mitochondria, and thus the mDNA.

Since there are many different lines of mDNA, you can use the mDNA to establish matrilineal descent, very much like you can use the Y chromosome to establish patrilineal descent. They are very different things, but provide very similar benefit for doing genetic-based genealogy.

tl;dr summary: The X sex chromosome doesn't provide any easy way to determine parentage, and probably won't until we get a large database built up that allows us to analyze random genetic sequences from any part of the genome and determine parentage from it. But the mDNA allows us to determine matrilineal descent immediately, much like the Y chromosome allows us to do with patrilineal descent.

4 hours ago, Carborendum said:

My primary premise being that if there was a gene pool already sufficiently close to modern human that it would generate the first human male, then within that same generation or the few successive generations of utaldi, other humans would also spontaneously form as well.  Thus parallel lines of humanity form from a similar gene pool.  And I see no reason why they need be from the same familial stock.  In fact, the randomness required would be aided, not hampered, by different genes.

Hmmm. I appear not to have done a very good job of explaining myself. This is problematic, because I don't know that I can do any better than I've already done.Let me give it a try.

A thousand generations from now, is it possible that I will still have surviving descendants? Sure. Is it possible YOU will still have surviving descendants? Again, sure. In fact, if we both have surviving descendants a thousand generations from now, it's likely that those descendants are the same people. They count both of us as grandfathers.

Now, let's pretend that they take the surname of their genetic father, and that this practice has been strictly followed for a thousand generations. Are these people named Carb or Vort? Maybe both, you say? Yes, maybe. Or maybe other names. But that's actually not very likely.

Suppose there are ten billion people around today. Suppose there are also ten billion people a thousand generations from now. Can it be that all of today's men have patrilineal descent a thousand generations later—in other words, that their "name survives" for a thousand generations? What are the odds that each man alive then traces his patrilineal ancestry back to a different man from today? Well, that's clearly impossible if we introduce concepts such as "brothers". Brothers share a common father, so that right there collapses the patrilineal lines.

In fact, if we look back a thousand generations, we do not find that all five billion men alive today have unique patrilineal ancestors. Quite the opposite, in fact. In my own family, I share my Y chromosome with both of my brothers, and my sons share that same chromosome with us and with my brothers' (genetic, biological) sons. All of my male cousins who are sons of my father's brothers (and there were six brothers) all share that same Y chromosome. And all of our grandfather's brothers' sons, and their sons, and their sons, share that same Y chromosome. When you get out to sixth or eighth cousins, we have an exceptionally varied set of ancestors, each of us inheriting from different people. BUT ALL OF US (VORTS) INHERIT OUR Y CHROMOSOMES FROM JUST ONE MAN. Not from countless millions of ancestors, but just from one.

If you trace back your genetic ancestry, the same thing is true. The Y-chromosome ancestry narrows very quickly between lines. Eventually, even though your ancestry is primarily east Asian and mine is primarily northern European, we will find that our Y chromosome is inherited ultimately from the same man. That man is "chromosomal Adam". Is that the same as the real Adam in the Bible? I don't know. Probably not. To even address the question, we would need a lot more information than we currently have about the descent of man and exactly what Adam's situation was in the world. But the point is that such a man must exist, a single male ancestor who provided the Y chromosome that all men living today carry.

The same is true, of course, for "chromosomal Eve" with respect to mitochondrial DNA.

When you think about it, this is pretty obvious stuff. Of course we can't have a billion different patrilineal (or matrilineal) lines simultaneously. Of course they have to collapse to a few lines, and ultimately to a single line. Yet this is what the article cited above is breathlessly telling us, as if it's some huge discovery and not common sense. ("Common sense" in that if you think about it long enough and work out examples, it eventually becomes obvious.) It's like having a news story telling about a huge discovery that dogs descended from wolves. Um, well, duh.

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17 hours ago, lostinwater said:

And i could be misunderstanding, but does anyone's mtDNA or yDNA have a time to live of more than 1?  Maybe, if you're really lucky, your child's mt/Y DNA is 100% like yours.  But most likely, it is 100% less a handful of mutations.

True, of course. But we have biological mechanisms to correct mutations, so the effective mutation rate is pretty low and appears to be predictable. (The rate of mutations, not the mutations themselves, which by definition are not predictable.) The point is that our Y chromosome "backbone", the basic Y chromosome underlying all humans, must converge on an individual some time in the past—200,000 or 300,000 years ago, according to the article. Even with mutations, there is a recognizable core of "human" Y chromosome inherited from "chromosomal Adam". Same with "chromosomal Eve" and her mitochondrial DNA.

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26524F03-3675-46A8-9376-670DCAD87F34.jpeg.630102df174c01c400b174de88d0c288.jpeg

 

Another example of good science.

 

Final paragraph of the original document

Michael Guillen  Ph.D., former Emmy-winning ABC News Science Editor, taught physics at Harvard and is now president of Spectacular Science Productions. His thriller, "The Null Prophecy," was released in July, 2017. His new book, "The End Of Life As We Know It: Ominous News From The Frontiers Of Science," is available now.

 

And 2 reviews of the mentioned book on Amazon.  Which I did not take the time to read...

A7FA7164-71F9-4DDF-876B-1BE5AD0CA134.thumb.png.29d478b4e3d1fd53c19270467204a610.png

 

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Edited by mikbone

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On 12/28/2018 at 1:36 PM, Vort said:

On the contrary, it's inevitable, unless by "survive" you mean "survive unmutated".

Not sure I follow why this might be so mind-boggling.

No, not really "unmutated".  I'm saying that given the randomness required for evolution and given that it is such a gradual process, it seems obvious to me that parallel development is a much more likely scenario.  Conversely, it seems to me that the single mutation scenario would be much less likely.

Then, given parallel development, it would seem that a single line over-running ALL others would be highly unlikely without some sort of major selecting event.

On 12/28/2018 at 1:36 PM, Vort said:

Not at all. Mitochondrial DNA (mDNA) is completely separate from chromosomal nuclear DNA. They are utterly different things.

OK.  Then I misunderstood what mDNA is.

On 12/28/2018 at 1:36 PM, Vort said:

A man passes on his Y (male sex) chromosome to his sons almost completely intact, except for some very tiny sections involved in meiotic swapping, and of course possible mutation. Thus, it is possible to determine a man's patrilineal descent simply by sequencing his Y chromosome. But a woman receives both parents' X sex chromosomes*, and when she passes an X sex chromosome onto a son or daughter, it is a composite of both parents' X sex chromosomes. So you can't use a woman's X chromosome to determine ancestry the way you use a man's Y chromosome.

That's as I said.  I just didn't understand that it was different than the mDNA.  My bad.

On 12/28/2018 at 1:36 PM, Vort said:

But mitochondria are a different story. Mitochondria are shaped and sized very much like bacteria, and they have their own bacteria-like DNA—not chromosomal like nuclear DNA, but circular, like bacteria have. The mDNA sequence is very tiny, but distinctive. The important part is that it's not involved with the nuclear DNA, but is completely separate. So you don't inherit your father's mitochondria or mitochondrial DNA; that comes strictly through the mother. Whatever mitochondria are present in the ovum, that's the mitochondria the child ends up with. And since Mama provides the ovum, she also provides the mitochondria, and thus the mDNA.

No one has been able to explain that to me so simply.  Thanks.

On 12/28/2018 at 1:36 PM, Vort said:

A thousand generations from now, is it possible that I will still have surviving descendants? Sure. Is it possible YOU will still have surviving descendants? Again, sure. In fact, if we both have surviving descendants a thousand generations from now, it's likely that those descendants are the same people. They count both of us as grandfathers.

This is beginning to sound very Harry Harrison-esque. (WotD)

On 12/28/2018 at 1:36 PM, Vort said:

Now, let's pretend that they take the surname of their genetic father, and that this practice has been strictly followed for a thousand generations. Are these people named Carb or Vort? Maybe both, you say? Yes, maybe. Or maybe other names. But that's actually not very likely.

Suppose there are ten billion people around today. Suppose there are also ten billion people a thousand generations from now. Can it be that all of today's men have patrilineal descent a thousand generations later—in other words, that their "name survives" for a thousand generations? What are the odds that each man alive then traces his patrilineal ancestry back to a different man from today? Well, that's clearly impossible if we introduce concepts such as "brothers". Brothers share a common father, so that right there collapses the patrilineal lines.

So far so good.  Yes, I understand all that.

On 12/28/2018 at 1:36 PM, Vort said:

In fact, if we look back a thousand generations, we do not find that all five billion men alive today have unique patrilineal ancestors. Quite the opposite, in fact. In my own family, I share my Y chromosome with both of my brothers, and my sons share that same chromosome with us and with my brothers' (genetic, biological) sons. All of my male cousins who are sons of my father's brothers (and there were six brothers) all share that same Y chromosome. And all of our grandfather's brothers' sons, and their sons, and their sons, share that same Y chromosome. When you get out to sixth or eighth cousins, we have an exceptionally varied set of ancestors, each of us inheriting from different people. BUT ALL OF US (VORTS) INHERIT OUR Y CHROMOSOMES FROM JUST ONE MAN. Not from countless millions of ancestors, but just from one.

Yup.

On 12/28/2018 at 1:36 PM, Vort said:

If you trace back your genetic ancestry, the same thing is true. The Y-chromosome ancestry narrows very quickly between lines. Eventually, even though your ancestry is primarily east Asian and mine is primarily northern European, we will find that our Y chromosome is inherited ultimately from the same man.

Here is where from an evolutionary position, I'm not buying it.  Parallel development.

On 12/28/2018 at 1:36 PM, Vort said:

That man is "chromosomal Adam".

Yes, we define that as the same thing.

On 12/28/2018 at 1:36 PM, Vort said:

Is that the same as the real Adam in the Bible? I don't know. Probably not. To even address the question, we would need a lot more information than we currently have about the descent of man and exactly what Adam's situation was in the world.

Irrelevant.  Once we go down the evolutionary paradigm, I'm not all that interested in trying to reconcile Biblical history with archaeological.  Yes, they can work together.  But for the purposes of this article we're discussing, I find it irrelevant.

On 12/28/2018 at 1:36 PM, Vort said:

But the point is that such a man must exist, a single male ancestor who provided the Y chromosome that all men living today carry.

If such a single common ancestor were the case, yes.  But I'm still having trouble believing that there necessarily was such a man.  It seem probabalistically impossible.

On 12/28/2018 at 1:36 PM, Vort said:

The same is true, of course, for "chromosomal Eve" with respect to mitochondrial DNA.

Understood.  Again, if it is the case.

On 12/28/2018 at 1:36 PM, Vort said:

When you think about it, this is pretty obvious stuff. Of course we can't have a billion different patrilineal (or matrilineal) lines simultaneously. Of course they have to collapse to a few lines, and ultimately to a single line. Yet this is what the article cited above is breathlessly telling us, as if it's some huge discovery and not common sense. ("Common sense" in that if you think about it long enough and work out examples, it eventually becomes obvious.) It's like having a news story telling about a huge discovery that dogs descended from wolves. Um, well, duh.

Let me get my thoughts together to explain my position.

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Guest

@Vort,

Since I've been busy this past week, I haven't had time to look through much of this thread.  But I have spent some time thinking about what the crux of the disparity is between our two positions.

You've primarily looked at it from our position looking backward.  I've primarily looked at it from our ancestors' positions looking forward.  I see that in your last marathon post to me, you made some effort to look at it from my position.  But then immediately shifted gears.  I'll try to address these two positions and see if we can see something.

LOOKING FORWARD:

You gave the example of all your descendants and all my descendants having offspring for thousands of generations.  Let's look at that.  If we ONLY take the two of us and ask how likely it is that both of us will have direct male-line descendants at that 3000th generation, the likelihood is low.  (Although, we both have large families.  So, that ups both our chances.  I  have five sons after all.)

However, if you have a sample of perhaps 20 viable males, this provides a different picture.  The likelihood that all 20 will have direct male-line descendants is very low.  But the likelihood that ONLY one will have direct male-line descendants is also low.  Now, increase that initial sample size of 20 to 100 or 1000 and the likelihood is less and less that only ONE will survive.

Randomness alone is not going to explain it.  A selecting even MUST have occurred.

LOOKING BACKWARD:

I see no evolutionary reason why we would look back 1000 generations and find that we had a common ancestor.  You've started with the assumption that there is going to be a narrowing of the field to one man.  Then constructed conclusions that would describe it.  And that would be valid IF the narrowing were a reality.

But if we assume parallel development, it doesn't paint that picture.  If there were 20 original human males and we completely ignore later arrivals (other Utaldi that developed later on into Sapiens) then we still have the likelihood that we may have a different male ancestor among the 20.  And with late arrivals, one of us could possibly be from one of the late arrivals -- completely different Y-chromosome than the others.

I don't see why the narrowing effect would winnow it down to a single ancestor unless we begin with that assumption and create circular logic to validate it.

So, try to explain why:

1) Parallel development would NOT be more probable than a single mutated human generating all of humanity.
2) How parallel development would make a common direct-line ancestor more likely.

That said, I do believe that we have evidence (not necessarily fact, but there is evidence) that a major selecting event occurred that did winnow down the population to a single tribe that would have a high probability of having a single male ancestor.  But that is due to the selecting event, not because of the probability of unimpeded DNA inheritance.

Edited by Guest

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You might find this to be interesting......

it sure does fit with the Old Earth plus Gap Theory. 

https://www.near-death.com/science/articles/richard-eby-and-secomd-coming-of-christ.html#a03

 

Quote

 

Jesus hesitated as I tried to capture the immensity of his explanations.

"You must understand, my son, that original creation mirrored the composition and perfection of Person-God. All creation vibrated in unison with us! There was total accord and harmony everywhere as the whole creation was resonating with and in God!

"Each separate thing or being thus carried out an appointed task in our scheme for the universe. A heaven-form of music resulted as even the stars sang in their appointed circuits. Here in paradise you are hearing these melodious vibrations directly upon your new mind, undistorted. On Earth you heard distorted sounds through the air waves. Throughout heaven the music flows from my throne, uninterrupted, undefiled, and peace-giving."

Jesus paused again.

"My book tells of the time when Lucifer's rebellion in heaven changed some things. He sought to usurp my Father's throne, assume his position as the most high God, and to rule the universe. For that blasphemy Lucifer was cast from heaven to Earth; in fact, I saw him fall as a bolt of lightning! In a tantrum of hate and rage over being deposed so fast he and his fallen angels disfigured our perfect Earth. It became void and uninhabitable. For punishment befitting his enemy of God, Lucifer was given a new name, Satan, since he was the self-appointed 'adversary' of the Almighty. Anything that God had made, Satan would attempt to destroy from then on. As Lucifer he had been created the highest angel about the throne, one of his assignments and talents being the chief musician in charge of worship and music. In his rebellious anger he set about destroying harmony on and in the Earth from then on. That is why the Earth where he operates now is out of harmony with God's other creations. In my book we call this disharmony 'sin', because it defies God's will that even the heavens declare the glory of God and the firmament show his handiwork.

"But be of good cheer, my son. The Father has permitted me to overcome Satan's world system of sin, and to destroy the works of Satan, and to re-establish righteousness in the hearts of my friends. Eventually in his chosen time he will restore all creation as it once was, in him!"

 

 

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On 1/10/2019 at 11:11 AM, MrShorty said:

Because the evidence for this mysterious extinction event is rooted in DNA and genetics and the assumptions about DNA and genetics that those making the claim use to make the claim.

How so? I would think an extinction event, such as an asteroid collision, would be in the geologic record more than somewhat questionable genetic evidence that is at least 7,000 years old. We have no idea how the genetics of our race have changed over the last few Decamillennia.

Edited by Emmanuel Goldstein

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If you haven't read the foxnews article linked in Vort's OP, you might do so. Part of the controversy over this is because there is nothing in the geologic record that suggests an extinction event 100k to 200k years ago.

Giving a quick outsider (I have nothing to do with the research, and only an undergrad level understanding of DNA and genetics from 20 years ago) explanation. By sequencing Y chromosome (only passed from father to son) and mitochondrial DNA (only passed from mother to child), and comparing samples from multiple people around the world, they observe that everyone seems to be descended from a single man (~200k years ago) and woman (~100k years) ago. They claim similar observations for 90% of species that they sequenced. Vort's point (if I understand it correctly) is that this observation should be true (everyone will appear to share common genetic ancestors if you go back far enough) whether there is an extinction event (or other population bottle neck) or not.

Dating is done by counting mutations (differences within samples) and then estimating how long since DNA lines separated using established mutation rates.

I don't know enough to argue whether the overall evidence is good or bad. It certainly seems like there is room to argue for insufficient evidence without something from geology to back up the claim.

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4 hours ago, MrShorty said:

If you haven't read the foxnews article linked in Vort's OP, you might do so. Part of the controversy over this is because there is nothing in the geologic record that suggests an extinction event 100k to 200k years ago.

Giving a quick outsider (I have nothing to do with the research, and only an undergrad level understanding of DNA and genetics from 20 years ago) explanation. By sequencing Y chromosome (only passed from father to son) and mitochondrial DNA (only passed from mother to child), and comparing samples from multiple people around the world, they observe that everyone seems to be descended from a single man (~200k years ago) and woman (~100k years) ago. They claim similar observations for 90% of species that they sequenced. Vort's point (if I understand it correctly) is that this observation should be true (everyone will appear to share common genetic ancestors if you go back far enough) whether there is an extinction event (or other population bottle neck) or not.

Dating is done by counting mutations (differences within samples) and then estimating how long since DNA lines separated using established mutation rates.

I don't know enough to argue whether the overall evidence is good or bad. It certainly seems like there is room to argue for insufficient evidence without something from geology to back up the claim.

But there was a very large meteorite impact around 10,500 BC in North America that destroyed all of the Mega Fauna of North America and plunged Earth into a mini ice age that lasted over a thousand years called the Younger Dryas period. It appears it also caused the sea levels world wide to rise drastically over just a couple days. The evidence is in the ice core samples and the geologic layers.

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On 12/27/2018 at 7:43 PM, Carborendum said:

I'm not sure if it is newsworthy.  But if we believe in the evolutionary beginnings of humanity, we do NOT have a single pair of human ancestors.  By the laws of probability, humanity would have many.  

However, prior to the rise of homo sapiens sapiens, the original ancestor must be that first single celled organism.

A single asexual microbe.

My belief is that G-d... is composed of fundamental or nearly fundamental energy......

and G-d in  a sense "evolved" in that G-d got better and better and better at creation over infinite time in the past.......

even planning an essentially infinite number of Big Bang type events...... and much later on......

Adam and Eve were created........

partly to fix up the mess began by the revolt of Covering Cherub Lucifer.....

 

www.CarbonBias.blogspot.ca/

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