Prokaryotes Versus Eukaryotes: Who is Hosting Whom?

Area of Science:

• Microbiology
• Evolutionary Biology
• Symbiosis

Background:

• Microorganisms constitute the majority of global biodiversity and have profoundly influenced eukaryotic evolution.
• The intestinal microbiome, often termed a "forgotten organ," significantly impacts host physiology and homeostasis.
• Mutualistic relationships between prokaryotes and eukaryotes are ancient, driving coevolution and diversification, particularly in phytophagous insects.

Purpose of the Study:

• To explore the intricate relationship between microbial mutualism and evolutionary diversification in prokaryote-eukaryote associations.
• To highlight the significant, yet understudied, impact of the gut microbiome on host biology and evolution.
• To stimulate empirical research into the mechanisms governing host-microbe interactions and their evolutionary consequences.

Main Methods:

• This study is primarily a conceptual review and theoretical postulation, encouraging empirical investigation.
• It synthesizes existing knowledge on host-microbe interactions and evolutionary diversification.
• It proposes a re-evaluation of host-microbe dynamics, questioning traditional perspectives.

Main Results:

• Prokaryotic microbes are a major selective force in eukaryotic evolution, outnumbering host cells significantly.
• The gut microbiome facilitates nutrient metabolism, immune system education, and regulation of various host physiological processes.
• Diversification in various lineages, including insects and mammals, is linked to microbial mutualisms and novel biochemistries.

Conclusions:

• The profound influence of the gut microbiome on host biology necessitates further research into the underlying mechanisms.
• The coevolutionary relationship between hosts and microbes challenges conventional views, prompting the question: "who is hosting whom?"
• Understanding these dynamics is critical for comprehending biodiversity and evolutionary trajectories.