Background

Bats are unique mammals that live abnormally long lives relative to their body size. In general, an animal's lifespan is proportional to its body size, but bats can survive for decades despite weighing only a few grams. In particular, the genus Myotis is known for an extremely wide range of lifespans. For example, the Brandt's Myotis (Myotis brandtii) can live over 50 years, whereas the Black Myotis (Myotis nigricans) typically lives only about seven years. This is analogous to the ninefold difference in lifespan between humans and Neanderthals. For years, the scientific community has sought to uncover the secrets behind bats' ability to resist severe infections, overcome cancer, and live long. However, high-quality data integrating cellular responses and genomic changes across species have been lacking. The absence of reliable experimental cell lines has also slowed comparative analyses of specific mechanisms.

Key Findings

Researchers from the University of California, Berkeley, completed high-quality genome sequences for eight species of Myotis bats and established cell lines derived from their wing tissues. Experiments were conducted to track cellular survival strategies by inducing DNA double-strand breaks using toxic chemicals. Analysis revealed that the longest-living species, the Little Brown Myotis (Myotis lucifugus), activates apoptosis-related genes immediately rather than attempting to repair damaged DNA. This strategy causes the cell to self-destruct before it can become cancerous. This 'discard rather than repair' approach mirrors the cancer suppression mechanism observed in elephants, another long-lived species. Through comparative genomic analysis, the research team also demonstrated the genetic co-evolution of longevity pathways and the immune system. In Myotis bats, longevity-associated genes and virus-interacting genes showed a highly overlapping relationship that goes well beyond random chance. Notably, these genes underwent rapid adaptive changes in regions encoding proteins that interact with DNA viruses such as herpesviruses and hepatitis B virus. This pattern contrasts sharply with the evolutionary trends in other mammals, including primates, which primarily evolve immune proteins in response to RNA viruses.

Significance and Prospects

This study supports the possibility that the secrets of animal longevity and viral immunity may share a common genetic origin. It marks a shift from the traditional view of age-related degenerative diseases and viral infections as separate phenomena. Understanding how bats suppress systemic inflammation while preventing cancer and controlling viral infections could provide new insights into human anti-aging strategies. However, there are limitations to directly applying the genetic mechanisms of bats to human clinical treatments. Overactivating the apoptosis switch could inhibit normal tissue regeneration, and the immune activity that maintains chronic infection in bats might instead trigger acute inflammation in humans. Therefore, follow-up research is needed to comprehensively evaluate the effects of artificial gene regulation on human immune homeostasis.