Speaker: Prof. Eric Libby, Umea University [website] [Icelab]

Title: The evolution of metabolic endosymbioses

Abstract: 

Metabolic endosymbioses—long-term partnerships in which one microbe lives inside another and exchanges metabolic resources—have played a pivotal role in the evolution of complex life, including the origin of mitochondria. Yet despite their potential, such associations remain rare, particularly among prokaryotes. In this talk, I focus on the evolutionary constraints that limit the emergence and persistence of metabolic endosymbioses. Two key challenges are metabolic compatibility between potential partners and the need for synchronized reproduction to ensure reliable transmission. Even when nutrient exchange is mutually beneficial, these partnerships often impose fitness costs or require coordination that natural selection may resist. Drawing on genome-scale models and theoretical approaches, I examine the conditions under which these constraints can be overcome—and why, in some cases, costly coordination strategies may nevertheless evolve. These findings offer a window into the selective pressures that shape symbiotic relationships and the evolutionary bottlenecks that may have constrained the origins of complex cellular life.