Recent genetic drift in the co-diversified gut bacterial symbionts of laboratory mice.

A recent study examined the gut bacterial strains found in laboratory mice and their evolutionary history compared to wild mice. The researchers found that the gut microbiota of laboratory mice has diverged from that of wild mice over the past 120 years of captivity, with laboratory mice experiencing an accelerated accumulation of genetic load. This divergence has led to differences in immune-cell proliferation, infection resistance, cancer progression, and the ability to model drug outcomes for humans. The study suggests that stochastic processes, such as bottlenecks, rather than natural selection, have been the main evolutionary forces driving the divergence of gut bacterial strains between laboratory and wild mice. The findings highlight the importance of restoring laboratory mice with wild gut bacterial strain diversity. [Extracted from the article]