The Human Microbiota as a Marker for Migrations of Individuals and Populations

Abstract

In this review, we discuss evidence that the microbes that constitute the human microbiota coevolved with humans and maintain complex community and host interactions. Because these microbes are mostly vertically transmitted, they have evolved within each human group and provide a view of human ancestry. In particular, we discuss using Helicobacter pylori as a marker of ancestry and migrations. Other organisms with more mixed vertical and horizontal transmission are not suitable to trace migrations with any fidelity. Human mixing affects microbial phylogeographic signals, and lifestyles impact the human microbiome population structure. A decade after the human genome was sequenced, we are gaining insights into the population structure of the human microbiome. We also examine whether, rather than focus on the genetics of single microbial populations, a wider approach to the study of human ancestry based on the human microbiome is now possible.

Sampling locality is more detectable than taxonomy or ecology in the gut microbiota of the brood-parasitic Brown-headed Cowbird (Molothrus ater)

“…Geographic distance can be positively correlated with microbiota dissimilarity (Dominguez-Bello & Blaser, 2011), but local flora and fauna, photoperiod, available food, climate conditions, etc. may all affect microbiota and differ by locality.…”

From Evolutionary Advantage to Disease Agents: Forensic Reevaluation of Host-Microbe Interactions and Pathogenicity

“…As a result of these characteristics, Helicobacter pylori has long been a prime candidate to determine past migrations (58–63), possible admixture (64) and genetic ancestry (65, 66) of current and ancient cultures. For instance, genetic admixture and past migrations are evident with the widespread presence of European H. pylori strains in North and South America, which are possibly remnants of massive colonial expansions, while in comparison rural Amerindian communities commonly harbor strains of Asian origins, products of pre-Columbian migrations to the New World (67–69).…”

Insights into human evolution from ancient and contemporary microbiome studies

“…Several of these pathobionts have been identified in ancient dental calculus [104], and further research may yield insights into the evolution of their pathogenicity [105]. Studies of pathobionts can also reveal information about past human migration events [155, 156]. A recent study of H. pylori recovered from the stomach tissue of the Tyrolean Iceman found that Asian strains predate African strains within Europe, indicating that the hybrid population of H. pylori found in Europe today is a recent development [125].…”

“…( n ) Gut microbes synthesize B and K vitamins [82, 83], catabolize xenobiotics, drugs, and toxins [65], and play key roles in cholesterol and bile acid metabolism [84]. ( o ) Some microbial strains exhibit patterns of genetic variation that mirror human migration histories [125, 155, 156]. …”