For the first time, German and American researchers use genome analysis to demonstrate population bottlenecks
Coincident with the arrival of Europeans in North and South America, there was a significant decline in the indigenous populations on both continents. This is what scientists working at Göttingen University and the University of Washington, Seattle, have demonstrated for the first time using genetic studies.
This was not only the first time that scientists used genetic data to demonstrate a significant bottleneck in Native American populations, but they were able to determine the breadth of the phenomenon as well. In their investigation, the researchers combined genetic information from "modern" and prehistoric humans living in North and South America. In total, they analysed 137 mitochondrial genomes and 63 old subsequences of this genome, the latter being between 800 and 5,000 years old. The mitochondrial genome is only passed on through the maternal lineage. Using sophisticated bioinformational methods, they showed how the indigenous population of America peaked around 5,000 years ago and then remained constant for millennia. Suddenly, around 500 years ago, the population contracted by around 50 percent.
"These losses were not limited to specific regions, but rather distributed across both American continents, with the severest impacts occurring in the most densely populated regions," the anthropologist Dr. Lars Fehren-Schmitz at Göttingen University explains, although this dramatic decline did not last very long. Soon, the indigenous population rapidly began to grow again.
Christopher Columbus is shown landing in the West Indies, on an island that the natives called Guanahani and he named San Salvador, on October 12, 1492 by John Vanderlyn (1775-1852)
Coincident with the arrival of Europeans in North and South America, there was a significant decline in the indigenous populations on both continents. This is what scientists working at Göttingen University and the University of Washington, Seattle, have demonstrated for the first time using genetic studies.
By extensively analysing female genomes, the researchers succeeded in proving that a transient contraction in population sizes by around 50 percent took place some 500 years ago. Their findings thus confirm historical records indicating how significantly the diseases, wars, famine and slavery brought over by the European settlers to the Americas affected the peoples living there. The findings of the study have been published online in the prestigious American journal Proceedings of the National Academy of Sciences.
Theodor de Bry: "Columbus’ landing in 1492". Copperplate engraving dated 1594.
Credit: Wikimedia Commons
This was not only the first time that scientists used genetic data to demonstrate a significant bottleneck in Native American populations, but they were able to determine the breadth of the phenomenon as well. In their investigation, the researchers combined genetic information from "modern" and prehistoric humans living in North and South America. In total, they analysed 137 mitochondrial genomes and 63 old subsequences of this genome, the latter being between 800 and 5,000 years old. The mitochondrial genome is only passed on through the maternal lineage. Using sophisticated bioinformational methods, they showed how the indigenous population of America peaked around 5,000 years ago and then remained constant for millennia. Suddenly, around 500 years ago, the population contracted by around 50 percent.
"These losses were not limited to specific regions, but rather distributed across both American continents, with the severest impacts occurring in the most densely populated regions," the anthropologist Dr. Lars Fehren-Schmitz at Göttingen University explains, although this dramatic decline did not last very long. Soon, the indigenous population rapidly began to grow again.
Credit: Wikimedia Commons
"This new population growth suggests that the cause of the decline can only be attributable to fast and short-acting factors, for example, from diseases brought over by the Europeans in combination with war and famine, and was not due to centuries-long processes, as is commonly assumed," Dr. Fehren-Schmitz adds.
Additionally, in their study, the scientists spatially reconstructed the historical population trends on the two continents by mapping the rapid spread along the coastlines and across the continents of the first humans to settle in America. Around 15,000 to 17,000 years ago, these peoples migrated from Asia by crossing the Bering Strait - which, today, lies below sea level. However, it was not until much later, after the individual groups had acclimated themselves to their new environments, that the population sizes grew substantially.
Additionally, in their study, the scientists spatially reconstructed the historical population trends on the two continents by mapping the rapid spread along the coastlines and across the continents of the first humans to settle in America. Around 15,000 to 17,000 years ago, these peoples migrated from Asia by crossing the Bering Strait - which, today, lies below sea level. However, it was not until much later, after the individual groups had acclimated themselves to their new environments, that the population sizes grew substantially.
Dr. Lars Fehren-Schmitz
Credit:
Georg-August University Göttingen
Original publication: Brendan D. O'Fallon, Lars Fehren-Schmitz. Native Americans experienced a strong population bottleneck coincident with European contact. Proceedings of the National Academy of Sciences of the USA - Early Edition. Doi: 10.1073/pnas.1112563108.
Contacts and sources:
Dr. Lars Fehren-Schmitz
Georg-August University Göttingen
Faculty of Biology
Johann-Friedrich-Blumenbach - Institute for Zoology and Anthropology
Original publication: Brendan D. O'Fallon, Lars Fehren-Schmitz. Native Americans experienced a strong population bottleneck coincident with European contact. Proceedings of the National Academy of Sciences of the USA - Early Edition. Doi: 10.1073/pnas.1112563108.
Contacts and sources:
Dr. Lars Fehren-Schmitz
Georg-August University Göttingen
Faculty of Biology
Johann-Friedrich-Blumenbach - Institute for Zoology and Anthropology
0 comments:
Post a Comment