It's a general rule in biology: Among mammals, the bigger you are, the longer you live. Yet bats defy this principle, making them among the longest-lived mammals relative to their size. The little brown bat, for example, is roughly the size of a field mouse. While it can live up to 34 years, a field mouse survives only a few months in the wild. A new study, co-led by researchers from Penn State and the University of Vermont, suggests that the secret behind the longevity of bats may be deeply intertwined with its unique ability to coexist with viruses.
Through analysis of nearly complete genomes of eight closely related species within the Myotis genus of bats - small, mouse-eared insect eaters - and studies of bat cells in the lab, the international research team found that bats developed an immune strategy for fighting viruses that differs from other mammals. Over millions of years, these bats have honed their ability to fight DNA viruses, like the smallpox and herpes viruses, while evolving a more flexible defense system to keep away fast-changing RNA viruses like influenza. It's this approach that has given bats the tools to fix their own cells and ward off disease of old age like cancer.
The study, published today (Aug 26) in Nature, describes new patterns of evolutionary adaptations for immunity and longevity. The findings suggest that in bats, a set of genes involved in both aging and immunity have been specifically curated through natural selection at the same time rather than refining these characteristics along separate and distinct molecular pathways.
