The Evolution of Human-Bacterial Interaction

Uncovering the Genetic Diversity and Origins of Pathogens

Introduction

  • Throughout history, humans have battled various diseases, including those of material nature.
  • Ancient records suggest that many diseases we know today existed thousands of years ago.
  • Different interpretations of these global epidemics were often attributed to our sins or other causes.
  • The question of where these pathogens originated from is intriguing.

Human Migration and Genetic Diversity

  • Modern humans originated in Eastern Africa and gradually migrated to different parts of the world.
  • Genomic analysis confirms that the highest genetic diversity is found in Eastern Africa.
  • As populations moved away from their original regions, genetic diversity decreased.
  • Genetic polymorphisms can provide insights into the spread of human populations.

Pathogens and Human Genetic Diversity

  • Genomic research allows us to study the genetic diversity of bacteria that infect humans.
  • Analyzing three important bacterial pathogens, tuberculosis, leprosy, and Helicobacter pylori, reveals interesting findings.
  • The genetic diversity of these pathogens aligns closely with the genetic diversity of human populations.
  • This suggests that humans were already infected with these pathogens in Eastern Africa before migration.

Possible Scenarios

  • Bacterial pathogens may have been acquired from animals as humans spread across the planet.
  • Alternatively, domesticated animals might have acquired diseases from humans.
  • Genomic research can provide insights into the origin and evolution of bacterial diversity.
  • The diversity of bacterial pathogens does not necessarily mirror human diversity, as they may have evolved independently.