Monday, March 14, 2011

We share an ancestor who probably lived no more than 640 years ago

This post has been revised and re-published. The original comments are preserved below. Typically this is done with posts that attract many visits at the time they are published, and whose topics become particularly relevant or need to be re-addressed at a later date.

25 comments:

Chris Masterjohn said...

Haha! You should share your estimation with the people who wrote this paper:

=======
Parsons et al. A high observed substitution rate in the human mitochondrial DNA control region. Nature Genetics. 1997;15(4):363-8.

http://lslab.lscore.ucla.edu/Mitochondria/pdf/mitoclock.pdf

"Using our empirical rate to calibrate the mtDNA molecular clock would result in an age of the mtDNA MRCA [most recent maternal common ancestor] of only ~6500 y.a., clearly incompatible with the known age of modern humans. Even acknowledging that the MRCA of mtDNA may be younger than the MRCA of mtDNA may be younger than the MRCA of modern humans, it remains implausible to explain the known geographic distribution of mtDNA sequence variation by human migration that occurred only in the last ~6500 years."
==========

Maybe the Genghis Khan figure from 640 years ago grew up in a population that remained very isolated for the previous 5900 years. LOL.

Chris

John said...

Approximately 250 million were alive on the entire planet when all the religious books were written.

I liken your example to that of a metaphysical triangle. Let's suppose that you are standing first in line at a movie theater for a premiere.

Behind you stands your parents, behind them, their parents, behind them etc. etc.

If a helicopter flew over a giant triangle of people would be visible in the parking lot. However if you stood looking at the line from the left, you would see about 200 people in my example.

Can the person in the front of the line yell back to the back of the line that there are no more tickets?

You bet they can, because it is only 200 people long, that amounts to 10,000 years of people.

Those at the back of the line, that heard the shouting, were called 'Prophets'. Those at the front were called 'traumatized'.

Taking into account that there are not 250 million people, but more than 6.5 billion people now, one can also liken this phenomena to that of a see-saw where the people at the back of the line are sitting, perpetually at an upward height simply because there are too many people on the other side.

When they go to sleep 'back then' they dream and slide down the see saw into our lives. Of course those that are capable of doing this are most probably the leaders, shamans, Royal families, etc.

What we see here then, is a commonality with another system, the computer bootstrap routine, we see humanity 'bootstrapping' itself into its destiny. It is a sad time when those that still listen to the people at the back of the line insist that they are right.

While some degree of truth is in their statements, most people less than 60 years ago could tell the difference between computer graphics of today and special effects on colour televisions in their dreams.

Ned Kock said...

Hi Chris. In all fairness, I would have to refer them to Dr. Chang’s article (linked in the post), which seems to refer to those types of studies when he says that: “Previous study of the time to a common ancestor of all present-day individuals has focused on models in which each individual has just one parent in the previous generation. For example, `mitochondrial Eve' is the most recent common ancestor (MRCA) when ancestry is defined only through maternal lines.”

Ned Kock said...

Hi John, I am not sure I understand what you are trying to say, but thanks for commenting anyway.

Chris Masterjohn said...

Thanks Ned, I'll try to check out the article. Thanks for a fresh perspective I have no education about, which may change soon if I find some time. :)

Chris

John said...

You were talking about time travel, I was attempting to explain to you how it works.

Ned Kock said...

I see John. Time travel – that would be VERY helpful in settling disputes about what our ancestors did or didn’t!

David Isaak said...

Wonderful post!

The "one-parent-in-previous-generation" model, which as you note is usually following mitochondrial (and therefore maternal) DNA, also automatically limits the reproductive potential.

A woman can't give birth more than once a year, and has a short period of lifetime fertility. Genghis not only has no effective bottleneck on annual reproductive rate, but can in principle continue from puberty until death.

Dr. B G said...

Awesome stuff ;)

*ha aah* Hey Cousin!!!!

What can I say?? I had no idea Khan had the largest continguous empire on earth in man's history. AND I AM CHINESE (who watched Star Trek).

Here was his empire:
http://www.lacma.org/khan/map.htm

National Geographic tracked his DNA -- thoughts?
http://news.nationalgeographic.com/news/2003/02/0214_030214_genghis.html

-G

David Isaak said...

"...AND I AM CHINESE..."

That's funny. I've spent a lot of time in China, and you'd think it was just yesterday that the Mongol hordes took the place over. The Han Chinese majority remember, and are still pretty cranky about it.

On the other hand, way out west in China, the Uighur people still think of themselves as Mongols rather than Chinese, and still use their own alphabet--even though Beijing doesn't approve.

There really weren't all that many Mongols, but they certainly were a problem. Hence the Great Wall. Hence the appearance of epicanthic folds over the eye in Iran, Germany, Hungary...

Pretty busy bunch, them Mongols.

Ned Kock said...

Right David. Btw, this idea has a number of implications, some more speculative than others. One is that our desperate infatuation with social status is due to evolutionary pressures that were progressively intensified as the size of human social groups increased.

Ned Kock said...

Hi G, my cousin, or maybe my sista from anotha mista.

The NatGeo piece is interesting, but I think that they made a mistake, which led them to underestimate how many people today can trace back their common ancestry to Khan.

They say that: “Geneticists use the Y-chromosome in population studies such as this because it doesn't recombine as other parts of the genome do … The Y-chromosome is passed on as a chunk of DNA from father to son, basically unchanged through generations except for random mutations.”

What is the problem? Well, Khan probably also had daughters …

gallier2 said...

And we should not forget that these Mongols were no agriculturists, they were (and still are) meat and milk people. I do not remember in which book (Sugar Blues may be) the author posited that the vast superiority of their warriors was because they didn't know sugar, citing texts from that time where they were noting that sugar made the enountered people soft and vulnerable.

Ned Kock said...
This comment has been removed by the author.
John said...

Our ancestors did what your cable provider showed people. They just didn't know what cable was when they were asleep.

Most of them however used it for to their advantage locally. Not everyone had the time to starve themselves and watch television remotely through their descendants.

They did, however offer up food and the likes to pay for the entertainment. Unfortunately it was paid to the wrong people.

Ned Kock said...

Hi Gallier. Yes, the traditional Mongols’ diet is as hardcore VLC as any I’ve seen so far. They eat the animal whole, fat and organs are cherished, and they also consume a lot of raw milk products. It is one of the most nutrient-dense diets one can possibly find. Unfortunately, the new generations are moving more and more toward the misguided Western dietary dogma – they find it so cool.

David Isaak said...

"And we should not forget that these Mongols were no agriculturists, they were (and still are) meat and milk people."

Oh, no! Not milk! That's so un-Paleo of them!

Ned Kock said...

As it happens, the richest source of carbs in the traditional Mongol diet is raw milk.

thhq said...

Previously I pulled 50 generations out of thin air (or maybe from reading fruit fly studies) as what I thought it would take us to devolve into the original Aryan. I still think I might be right if you're saying that 25 generations gets us back as far as Genghis.

My question remains unanswered. Why would I want to go back there? And even a time trip is a good thing, eating a VLC diet is not a time machine that will turn me into a Mongol.

John said...

Lets say you are on your way to work and suddenly, hypothetically, you are in a car accident and sustain brain damage. You end up in an ICU unit, trying to stay alive. You may end up back there as your brain strives to keep you alive.

Chris Masterjohn said...

Hey Ned!

These folks are using mtDNA but this sounds awfully consonant with your post:

http://blogs.discovermagazine.com/gnxp/2011/04/modern-europeans-modeled-as-middle-eastern-farmers

http://tinyurl.com/4yu7e7j

Chris

Stan (Heretic) said...

Hi Ned,

Your model and its conclusions are most likely inaccurate because it strongly depends on population clustering and thus on the higher orders of the distribution function. It reminds me of the "white sky" paradox in astronomy: even in an absence of Hubble expansion, in an infinite universe you can still get black sky (or white sky or in-between) with the same constant average volume density of stars, depending on how do you cluster the stars.

With the population models, you can have entire world population living in weakly communicating thus genetically weakly related or unrelated village communities, where within each village people would have been very closely related. You can then have groups of villages clustered together into tribes, which would have had almost zero contacts with other tribes thus no common ancestors, etc.

Ned Kock said...

Hi Chris, thanks.

Ned Kock said...

Hi Stan. We cannot underestimate the human drive to migrate. A successful isolated tribe will grow in size, which at some point will provide a strong stimulus for migration due to limited resources.

An isolated tribe that is kept small due to a harsh environment will either migrate or have some of its members migrate; otherwise the tribe will eventually disappear.

Humans also migrate just simply because they want to, which is probably what led our African ancestors to migrate to Europe, becoming the Cro-Magnons.

Anonymous said...

Did anyone take in to account that MAYBE no one migrated and the northern climate simply got COLDER?

We know that dinosaurs were much bigger lizard like land animals which required huge amounts of energy and had the lizard like skin to protect themselves from high amounts of UV radiation. Bigger animals points to a bigger Sun and a lot more vegetation to support life of these huge creatures.

I don't buy the one ancestor theory because it points to incest and we know how successful incest birth is. There is powers way beyond our understanding of "where" we actually are in this vast universe or simply, "who" created these complex biochemical vehicles.