Population genetics reveals shared ancestries

More than just a tool for predicting health, modern genetics is upending long-held assumptions about who we are. A new study by Harvard researchers casts new light on the intermingling and migration of European, Middle Eastern and African and populations since ancient times.

In a paper titled "The History of African into Southern Europeans, Levantines and Jews," published in , HMS Associate Professor of Genetics David Reich and his colleagues investigated the proportion of sub-Saharan present in various populations in West Eurasia, defined as the geographic area spanning modern Europe and the Middle East. While previous studies have established that such shared ancestry exists, they have not indicated to what degree or how far back the mixing of populations can be traced.

Analyzing publicly available from 40 populations comprising North Africans, Middle Easterners and Central Asians were doctoral student Priya Moorjani and Alkes Price, an assistant professor in the Program in Molecular and Genetic Epidemiology within the Department of Epidemiology at the Harvard School of Public Health.

Moorjani traced genetic ancestry using a method called rolloff. This platform, developed in the Reich lab, compares the size and composition of stretches of DNA between two as a means of estimating when they mixed. The smaller and more broken up the DNA segments, the older the date of mixture.

Moorjani used the technique to examine the genomes of modern West Eurasian populations to find signatures of Sub-Saharan African ancestry. She did this by looking for chromosomal segments in West Eurasian DNA that closely matched those of Sub-Saharan Africans. By plotting the distribution of these segments and estimating their rate of genetic decay, Reich's lab was able to determine the proportion of African genetic ancestry still present, and to infer approximately when the West Eurasian and Sub-Saharan mixed.

"The genetic decay happens very slowly," Moorjani explained, "so today, thousands of years later, there is enough evidence for us to estimate the date of population mixture."

While the researchers detected no African genetic signatures in Northern European populations, they found a distinct presence of African ancestry in Southern European, Middle Eastern and Jewish populations. Modern southern European groups can attribute about 1 to 3 percent of their genetic signature to African ancestry, with the intermingling of populations dating back 55 generations, on average—that is, to roughly 1,600 years ago. Middle Eastern groups have inherited about 4 to 15 percent, with the mixing of populations dating back roughly 32 generations. A diverse array of Jewish populations can date their Sub-Saharan African ancestry back roughly 72 generations, on average, accounting for 3 to 5 percent of their genetic makeup today.

According to Reich, these findings address a long-standing debate over African multicultural influences in Europe. The dates of population mixtures are consistent with documented historical events. For example, the mixing of African and southern European populations coincides with events during the Roman Empire and Arab migrations that followed. The older-mixture dates among African and Jewish populations are consistent with events in biblical times, such as the Jewish diaspora that occurred in 8th to 6th century BC.

"Our study doesn't prove that the African ancestry is associated with migrations associated with events in the Bible documented by archeologists," Reich says, "but it's interesting to speculate."

Reich was surprised to see any level of shared between the Ashkenazi and non-Ashkenazi Jewish groups. "I've never been convinced they were actually related to each other," Reich says, but he now concludes that his lab's findings have significant cultural and genetic implications. " boundaries that many people think are impermeable are, in fact, not that way."

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jmcanoy1860
4.4 / 5 (7) May 24, 2011
Predictably a wild cretin appears to once again spread ignorance and idiocy. Unless the ark was in South Africa or the African rift valley then this further disproves genesis. Last I checked there were no "mountains" there, 6000 years is not enough time to create the various races or their distributions, the separate languages, etc etc etc. But of course this is falling on deaf ears. Remind me again....what is the evidence for genesis outside of a mistranslated book of sheep herder fables? oh right......there are none.
daisrael
4.2 / 5 (5) May 24, 2011
LOL...
Everyone is related anyway, because every person alive has Noah as their paternal ancestor, and within the set of all living persons, every person alive has one of his three sons as their paternal ancestor on at least one side of their family.


Given that the christian mythology has some accurate historical references, citing the Noah fable is far from scientific. Unless you can reasonably explain the isolation of species, lack of enough water to submerge the whole planet, or a myriad of other simple logical hurdles that the religious mind tends to over look to accommodate their supernatural fantasy citing Noah as a ancestor is profoundly stupid(with all do respect).
LuckyBrandon
3 / 5 (4) May 24, 2011
the key word there is "some accurate"...as in places...thats about it...in regards to the noah story, well, that pretty much ends with the fact that there would be geologic evidence for such a flood, for which none exists. Its either complete bs, or more likely a local flood (such as the dead lake turning to the dead sea), and the story just happened to be passed down, and surprise surprise, greatly exxagerated.
kevinrtrs
1 / 5 (11) May 25, 2011
lack of enough water to submerge the whole planet,

are you not aware that if you level the land masses and ocean valleys there's enough water on earth to cover the planet about a kilometer deep?
6000 years is not enough time to create the various races or their distributions, the separate languages

At the tower of Babel incident, God created numerous new languages in one fell swoop. As for the distributions and population growth perhaps you are relying on uniformitarian thought that things tend to happen slowly over a long period of time. Reality dictates otherwise. In most cases, including distributions and ecologic system formations, things happen very rapidly indeed, in hundreds of years instead of millions. Ignore evolutionary ideals for a moment and look at reality. The answers lie there.
kevinrtrs
1 / 5 (12) May 25, 2011
that pretty much ends with the fact that there would be geologic evidence for such a flood, for which none exists

Geologists are beginning to calculate just how much energy is required to move rocks tens/hundreds of miles away from their original resting places. They are also beginning to calculate just how much water and hence power/force is required to create canyons like the Grand Canyon. Guess what? The energies involved can only be created by massive catastrophic floods of biblical proportions. There is now an exciting wide-spread interest in this field of thought. You might want to check it out for yourself.
It should be clear just by looking at it that the puny [in comparison] Colorado river could not have created the vast swathe of the grand canyon. Something very powerful and massive [many miles wide] had to have moved very quickly and forcefully to cut through the landscape.
Now take that kind of evidence globally and you have the aftermath of Noah's flood.
TheRedComet
5 / 5 (4) May 25, 2011
kevinrtrs
You are right on it would take a huge flood in order to make the grand cannon with in 6000 years. But wait the Colorado river established its current path roughly 17 million years ago.
Gawad
5 / 5 (4) May 25, 2011
LOL...
Much biblical garbage deleted.
Everyone is related anyway, because every person alive has Noah as their paternal ancestor, and within the set of all living persons, every person alive has one of his three sons as their paternal ancestor on at least one side of their family.
QC, your garbage has been reported as abuse.
Rutzs
4 / 5 (5) May 25, 2011
Please keep your religious fairy tales to your religious forums/websites.

This is a place of science FACT, not science fiction.

It makes me truly sad that, even to this day, people still believe in magic...

I know! I'm going to start my own religion! Good way to make some money, and control a population.
spectator
1.2 / 5 (5) May 25, 2011
Unless you can reasonably explain the isolation of species, lack of enough water to submerge the whole planet, or a myriad of other simple logical hurdles that the religious mind tends to over look to accommodate their supernatural fantasy citing Noah as a ancestor is profoundly stupid(with all do respect).


I actually thought of a way to flood the whole planet, even without God miraculously creating or removing new water.

One way: Glaciation.

Consider this. I calculated that given the amount of water on the planet, 1.23E18 cubic meters, and assuming a cubit is 18 inches, then 15 cubits above the mountains comes to 22.5ft, or ~7 meters.

Now imagine if you covered all of the land in ICE 7 meters thick, without attempting to fill the "volume" of the assumed shell at the height of everest. This allows a 7 meter thick layer of ice on the mountain surfaces and all terrain surfaces, which technically meets the requirement described in the Bible. see below...
spectator
1 / 5 (4) May 25, 2011
After some math, I find the surface of a spheriod with radius equal to the Earth comes to 162 trillion square meters, or 1.62E14.

Now since the surface of the Earth is not smooth, and contains mountains and valleys and stuff, we will double this number for the sake of argument, which is a bit unfair because there's no way topography doubles the surface area given a significant unit of measure of one meter, but I'll just let that alone.

Now, if you divide the volume of water by the surface area, even having doubled the surface to account for topography, and even neglecting the expansion factor for ice being less dense than water, you find there is actually enough water such that, if it were precipitated onto land and frozen on contact, it could coat every surface of the entire earth, both continents and ocean floors, to a thickness of 3790 meters.

There is technically somewhere between 500 and 1000 times more water on Earth than is needed, given this interpretation.
spectator
1 / 5 (6) May 25, 2011
Also, that interpretation fits with the notion that the "fountains of the deep" refers to volcanic and/or hydrothermal systems, seeing as how a supervolcano can both explain the lava floes on TOP of ancient human remains in Africa, AND explain the necessary global cooling event that would produce world wide catastrophic glaciation within a matter of 40 days original precipitation event, though he was actually in the Ark significantly longer than that.

QC, your garbage has been reported as abuse.


My "Garbage" was relevant because the topic is partly about mideast history and the origin of humanity.

Also, have you ever bothered to consider that the human fossils in Africa are pre-flood fossils, and Africa was re-populated after the flood?
spectator
1 / 5 (5) May 25, 2011
Yes, the low feedback truly, truly hurts my feelings....

Not...

Actually, it's hilarious. He asked for an explaination, and I have given one which even manages to be consistent with his own world view while not technically violating the Biblical account.

Your negative feedback is a joke, really.
SteveL
5 / 5 (4) May 25, 2011
lack of enough water to submerge the whole planet,

are you not aware that if you level the land masses and ocean valleys there's enough water on earth to cover the planet about a kilometer deep?

Are you not aware that for the earth to recover from such an event in 5,000 years would entail tetonic and volcanic activity of such magnitude that this world would still be poisoned beyond our ability to live?
LuckyBrandon
3 / 5 (2) May 27, 2011
@kevinrts-you are way off base, glaciers contain that power, much more so than would liquid water. You can test this yourself pretty easily by making dirty ice mixed with a slightly high water content (to give it a tad bit of movement), put heavy rocks into a bin of some sort, then tilt it up...that will take the majority, if not all, of the stones...now try the same with liquid water....you won't get the same result...the lab glacier you just built will strip those rocks away...
CSharpner
5 / 5 (1) Jun 06, 2011
Kev & GC. When was the flood? Why didn't the Egyptians notice? If the universe is only 6000 years old, why do we see objects more than 6000 light years away? There are SO MANY physical observations that disprove a young Earth as to be ridiculous to continue to publicly state otherwise. The crazy stuff you have to finagle to try to fit a young Earth to known observations is laughable.