Coevolution of the bacterial cause of gastric cancer has been demonstrated for the first time by researchers from Vanderbilt University Medical Center, Dartmouth College, the University of Nariño in Colombia, Universidad del Valle in Colombia, Holmes Regional Medical Center in Melbourne, Florida, and the Department of Veterans Affairs in Nashville, Tennessee in a report in the Jan. 13, 2014, edition of the journal Proceedings of the National Academy of Sciences.
The study populations were two small towns in and near Tumaco, Colombia.
The population of the coastal town was in majority of African descent. The people were brought to Colombia as slaves by the Spanish. The mountain community near Tumaco was in majority of Amerindian descent.
The mountain community demonstrated a rate of gastric cancer caused by the bacterium Helicobacter pylori that was 25 times higher than the coastal community.
Through DNA testing the researchers determined that the people that originally came from Africa had a genetic protection against the bacteria that causes gastric cancer that either was acquired in the early evolution of man in Africa or was acquired by association with Europeans.
The Amerindian residents immigrated from China and Russia during the Ice Age. These people had not developed any immunity to Helicobacter pylori and acquired the bacterium from the Spanish Conquistadors.
The difference in development of gastric cancer is directly related to the development of immunity to the bacterium that causes gastric cancer and was a function of the coevolution of the immunity to the bacterium in one population that was exposed for a long period of time to the disease vector.