Post by anansi on May 5, 2015 19:24:25 GMT -5
Ancient DNA Tells a New Human Story
Armed with old bones and new DNA sequencing technology, scientists are getting a much better understanding of the prehistory of the human species, writes Matt Ridley
A stone projectile point embedded in Kennewick Man’s right hip gave researchers the first clue that he belonged to an ancient human population; the spear point likely became lodged following an adversarial encounter. PHOTO: CHIP CLARK, SMITHSONIAN INSTITUTION
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If this is suggesting what I think it is, then there is evidence of African contact with the America's 6kyrs ago.
Xman this is your turf looking into this, now get to work..
Armed with old bones and new DNA sequencing technology, scientists are getting a much better understanding of the prehistory of the human species, writes Matt Ridley
A stone projectile point embedded in Kennewick Man’s right hip gave researchers the first clue that he belonged to an ancient human population; the spear point likely became lodged following an adversarial encounter. PHOTO: CHIP CLARK, SMITHSONIAN INSTITUTION
Imagine what it must have been like to look through the first telescopes or the first microscopes, or to see the bottom of the sea as clearly as if the water were gin. This is how students of human prehistory are starting to feel, thanks to a new ability to study ancient DNA extracted from bodies and bones in archaeological sites.
Low-cost, high-throughput DNA sequencing—a technique in which millions of DNA base-pairs are automatically read in parallel—appeared on the scene less than a decade ago. It has already transformed our ability to see just how the genes of human beings, their domestic animals and their diseases have changed over thousands or tens of thousands of years.
The result is a crop of new insights into precisely what happened to our ancestors: when and where they migrated, how much they intermarried with those they met along the way and how their natures changed as a result of evolutionary pressures. DNA from living people has already shed some light on these questions. Ancient DNA has now dramatically deepened—and sometimes contradicted—those answers, providing a much more dynamic view of the past.
Low-cost, high-throughput DNA sequencing—a technique in which millions of DNA base-pairs are automatically read in parallel—appeared on the scene less than a decade ago. It has already transformed our ability to see just how the genes of human beings, their domestic animals and their diseases have changed over thousands or tens of thousands of years.
The result is a crop of new insights into precisely what happened to our ancestors: when and where they migrated, how much they intermarried with those they met along the way and how their natures changed as a result of evolutionary pressures. DNA from living people has already shed some light on these questions. Ancient DNA has now dramatically deepened—and sometimes contradicted—those answers, providing a much more dynamic view of the past.
It turns out that, in the prehistory of our species, almost all of us were invaders and usurpers and miscegenators. This scientific revelation is interesting in its own right, but it may have the added benefit of encouraging people today to worry a bit less about cultural change, racial mixing and immigration.
Consider two startling examples of how ancient DNA has solved long-standing scientific enigmas. Tuberculosis in the Americas today is derived from a genetic strain of the disease brought by European settlers. That is no great surprise. But there’s a twist: 1,000-year-old mummies found in Peru show symptoms of TB as well. How can this be—500 years before any Europeans set foot in the Americas?
Consider two startling examples of how ancient DNA has solved long-standing scientific enigmas. Tuberculosis in the Americas today is derived from a genetic strain of the disease brought by European settlers. That is no great surprise. But there’s a twist: 1,000-year-old mummies found in Peru show symptoms of TB as well. How can this be—500 years before any Europeans set foot in the Americas?
In a study published late last year in the journal Nature, Johannes Krause of the Max Planck Institute for the Science of Human History in Jena, Germany, and his colleagues found that all human strains of tuberculosis share a common ancestor in Africa about 6,000 years ago. The implication is that this is when and where human beings first picked up TB. It is much later than other scientists had thought, but Dr. Krause’s finding only deepened the mystery of the Peruvian mummies, since by then, their ancestors had long since left Africa.
Modern DNA cannot help with this problem, but reading the DNA of the tuberculosis bacteria in the mummies allowed Dr. Krause to suggest an extraordinary explanation. The TB DNA in the mummies most resembles the DNA of TB in seals, which resembles that of TB in goats in Africa, which resembles that of the earliest strains in African people. So perhaps Africans gave tuberculosis to their goats, which gave it to seals, which crossed the Atlantic and gave it to native Americans.
Modern DNA cannot help with this problem, but reading the DNA of the tuberculosis bacteria in the mummies allowed Dr. Krause to suggest an extraordinary explanation. The TB DNA in the mummies most resembles the DNA of TB in seals, which resembles that of TB in goats in Africa, which resembles that of the earliest strains in African people. So perhaps Africans gave tuberculosis to their goats, which gave it to seals, which crossed the Atlantic and gave it to native Americans.
Another genetic puzzle has been the fact that most modern Europeans have certain DNA sequences that are similar to those of some American Indians but different from those of most Asians, including natives of Siberia. How can this be, since American Indians are supposedly descended from Asians who migrated across the Bering land bridge from Siberia to Alaska about 14,000 years ago? Were there ancient seafarers in the Atlantic? Or is it simply from mating between European settlers and American Indians after Columbus? Neither, as it happens.
link
Klik for more^
If this is suggesting what I think it is, then there is evidence of African contact with the America's 6kyrs ago.
Xman this is your turf looking into this, now get to work..
