Posted on 05/24/2011 1:06:30 PM PDT by decimon
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 Gene Flow into Southern Europeans, Levantines and Jews," published in PLoS Genetics, HMS Associate Professor of Genetics David Reich and his colleagues investigated the proportion of sub-Saharan African ancestry 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 genetic data 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 human populations 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 African populations 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 ancestry 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. "Population boundaries that many people think are impermeable are, in fact, not that way."
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***Languages mark who was in charge at the time.***
You betchyah!!
Communication defines us - so an enduring, dominant language is in fact ‘the coin of the realm’.
One of my premier dictionaries had a flow chart of all the World’s languages - showing the fusion of one into another. Fascinating.
Then I lost it!!!!!
Here's a line I just happened to have read, and underlined, about one hour ago.
It was the greatest sensation of existence: not to trust, but to know.
Not at all surprising. I have one relative and one friend who look like they could be sisters. They both have the same tan skin, the same long beautiful brown ringlety hair. Their facial features are rounded, they have full lips. They are both quite pretty. One is of Jewish ancestry, the other has a black dad and white mom.
We know they drove chariots rode horses and herded sheep because the words involved are all basically the same in all Indo-European languages.
"It was the greatest sensation of existence: not to trust, but to know."
Followed by "Do they call it a low, animal joy -- this feeling that I would not care if the rail did break to bits under us now -- it won't -- but I wouldn't care, because I have experienced this? A low, physical, material, degrading pleasure of the body?"
and
"Their soul is in every man who has the capacity to equal this achievement. Should the soul vanish from the earth, the motors would stop, because that is the power which keeps them going..."
Such is the 'power' of fallacy. One thinks something is 'known' when it is not known at all.
Language has an interesting parallel to **micro** evolution.
I find it interesting the most compelling arguments against macro-evolution are coming from mathematicians and statisticians.
Amazing how much creationist rely upon lawyers mathematicians and statisticians to comment on a subject none of them even understands.
Population genetics among all humans show the same markers of common descent in miniature that we see between humans and all other primates.
You can deny it until you are blue in the face - but it doesn't help matters much that you have no clue at all what those markers are and what they mean.
The same method to determine that Amerindians are more closely related to Siberian Asians than any other human population are the exact same method that shows that humans are more closely related to chimpanzees (and chimpanzees are more closely related to humans) than either is to any other primate.
You should also know the difference between micro-evolution and macro-evolution.
But ...
Such is the 'power' of fallacy. One thinks something is 'known' when it is not known at all.
How do you know that?
Are you trying to use the "Who is to say" fallacy?
There is no mechanistic difference between the evolution we see within a single species - and the evolution we see that creates different species from a common ancestor.
The same markers we see showing the common ancestry of all dogs and wolves and the same markers we see showing the common ancestry of primates and humans.
You can say it isn't so all you want - but it would help if you knew and understood what those markers are. You don't.
Seriously, Indo-European linguistics is fascinating--a lot can be learned about the "Proto-Indo-Europeans" from studying the words inherited by the daughter languages. There are sometimes striking similarities in inherited words and customs as far apart as India, Italy, and Ireland.
They do seem to have been very warlike--"to live by war and plunder is of all things most glorious" as Herodotus said of the Thracians (Indo-European-speakers).
Oh what a tangled web we weave, When first we practice to deceive
Sir Walter Scott
In the modern world things are invented and the name for it spreads with the invention.
In the ancient world things were often independently discovered or developed - and thus different words were used to describe them (books, letters, etc).
I sometimes joke to anyone who tells me they are “Persian” that I am a “Thracian” or “Sarmatian” - usually they don't get the joke.
Finnish, Estonian, and Hungarian are not "Indo-European" languages but belong to the "Finno-Ugric" family--their words for "100" are of Indo-European origin. The Hungarian words for Wednesday, Thursday, Friday, and Saturday come from a Slavic language. The English colonists of Virginia took the words for "tomahawk," "mocassin," and "opossum" from the local Indians.
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