The Tsimshian peoples’ ancient genomes left revelatory traces on their past, indicating that 6,000 years ago the size of the Tsimshian population declined in a sluggish but steady manner.
This study reports the results of the first population-wide DNA examination of a population of Native Americans since ancient times to the present day, as described in the American Journal of Human Genetics.
Until now, it was thought that once Native Americans had crossed the Bering Strait, all of their populations were growing in size by the time the Europeans arrived. For this population, at least, the researchers have proven otherwise.
“The analysis of old nuclear DNA is a relatively new field,” said John Lindo from the Emory University’s Department of Anthropology.
The nuclear DNA gives insights regarding a person’s bloodline that can go thousands of years back in time. Lindo is among the handful of geneticists seeking to sequence entire ancient genomes of Native Americans. Lindo is especially concerned about the way in which the DNA of different groups of ancient people have developed through time.
The Tsimshian people DNA evolved continuously and their modern-day representatives present more varied genomes
The Tsimshian people have lived in Southern Alaska and on the coastal British Columbia, and their main occupation was fishing.
For this study, John Lindo, assisted by his team, managed to sequence the DNA of 25 ancient Tsimshian people and 25 modern-day representatives of this particular group of Native Americans.
The researchers demonstrated the continuous evolution of this population, despite the science community’s believes in this regard. In the preliminary results, Lindo and his team noticed huge differences between ancient Tsimshian DNA and modern-day representatives’ DNA, especially in the genes related to the immune system.
Lindo explained that, due to increasing exposure to pathogens, the DNA mutated naturally in the genes related to immunity for a better adaptation to illnesses.
The Tsimshian population has been decimated by the smallpox epidemy brought by the Europeans during their colonization of the Americas. However, according to Lindo, the intermarriages of the remaining Tsimshian people with other Native Americans groups and Europeans led to a diversification of their ancient genomes, which is a good thing, in fact, since “a population with relatively high genetic diversity has a greater potential to fight off pathogens and avoid recessive traits,” as Lindo himself explains.