Kevin Guzman, Lidia Montenegro and Alvaro Pazos
Background: The Helicobacter pylori (H. pylori) has evolved with its human host by nearly 110,000 years. Despite that H. pylori has been considered as a main factor for gastric cancer (GC) development, the pathogenesis depends on its hosts evolutive relations.
Objective: In this study we analyzed the H. pylori evolutive relations of two populations with different GC risk in Colombia.
Materials and methods: We study 10 human genomes and same number of H. pylori genomes from Tuquerres: high GC risk population, and 9 genomes from Tumaco: low GC risk population. The evolutive analysis was performed using MLST, vacA virulence gene and alpA adhesine gene for H. pylori and human ancestry by phylogenomic analyzes.
Results: We found that the studied people from Tumaco had marked African and Amerindian ancestry and in minor proportion European ancestry. In contrast, the studied human population from Tuquerres had mainly Amerindian and European ancestry. The H. pylori phylogenomic trees from Tumaco were grouped with African strains (hspWAfrica y hpAfrica2) in 56% and with the Colombian evolutive group (hspColombia) in 44%. We found that the H. pylori genomes from Tumaco are in major proportion in co-evolution with its human host genomes. In Tuquerres the phylogenomic trees grouped in 80% with local H. pylori strains (hspColombia) and the 20% of genomes grouped with hspWAfrica ancestors. Also, we found that H. pylori from Tuquerres were in minor proportion in co evolution with its human host genomes. In Tuquerres the H. pylori vacA and alpA genes showed phylogenetic relationship with Amerindian strains (hspAmerindian) and European (hpEurope), and in minor proportion with African strains (hspWAfrica y hpAfrica2) and Asian (hpEAsia).
Conclusion: The marked difference of GC risk in Colombian populations could be explained by the genome coevolution time between Helicobacter pylori and human host genomes.
