Coevolution in News

Co-evolution between humans, bacteria reduces gastric cancer risk, research suggests

• Colombian villages and found that if you have Helicobacter pylori bacteriadepends the risk of gastric cancer caused on both the ancestry of the person and the ancestry of the microbe they carry. Half of the world's population is injected with H. pylori. but only minor gastric problems. Gastric cancer is the second caused death in the world.

http://www.sciencedaily.com/releases/2014/01/140115143707.htm
Questions:

1. What are the two places in Columbia Williams Research team studied?
2. Which ethnicity were you if you had the H. pylori disease?
3. What is the relation between ancestry and H.pylori?
4. How does co-evolution play a part in this disease?
5. Why does Dr.Jay Dunlap think that, "These data provide a remarkable example of coevolution between humans and the natural world; in particular, the microbial environment,"?