The world’s oldest dog, Bluey, an Australian cattle dog, lived to the impressive age of 29. However, the average lifespan for most dogs is just 10 to 13 years. This raises the question: why do dogs have such a shorter lifespan compared to other mammals, such as the rhino, which can live up to 50 years?
Understanding Lifespan Variations Among Mammals
Mammals have vastly different lifespans, ranging from short-lived species like the shrew, which barely survives its first year, to the bowhead whale, which can live for over two centuries. Past studies have suggested that animals with larger brains relative to their body size tend to live longer. However, a recent study published in Scientific Reports suggests that the key to longevity lies in the immune system.
Gene Families and Longevity
Researchers set out to explore how specific genes contribute to longevity by comparing the maximum lifespan potential (MLSP) of different mammals. MLSP refers to the age of the longest-lived individual of each species, like the 122-year lifespan of Jeanne Louise Calment, the longest-living human on record.
While an animal’s average lifespan may depend on resources and predation risks, MLSP is a biological limit determined by the body’s ability to manage aging, repair cells, and fend off diseases. The study found that mammals with longer lifespans tended to have expanded gene families that enhance immune system functions.
Gene Families and Their Impact
Gene families are groups of related genes that evolve together. The expansion or contraction of these gene families can significantly affect an animal’s physical traits and lifespan. For instance, the long-lived bowhead whale has specific genetic adaptations that promote DNA repair, improve cell-cycle regulation, and prevent cancer. Similarly, elephants possess genes that aid in DNA repair and suppress tumor growth.
The researchers analyzed over 4,000 gene families across 46 mammalian species and identified 236 gene families that had a significant impact on MLSP. Those linked to a longer lifespan were often related to immune functions, helping the body repair damaged cells, reduce inflammation, and fight infections.
Brain Size and Lifespan: A Shared Evolutionary Path
Interestingly, the study also found that gene families associated with larger brain sizes were also linked to longer lifespans. Out of 184 gene families connected to brain size (in relation to body mass), 161 were also tied to a longer MLSP. This suggests that the evolution of a bigger brain and longer life might have gone hand in hand. However, this correlation didn’t apply to factors like longer gestation periods or age of sexual maturity, which also contribute to lifespan.
Conclusion
The study highlights the crucial role of gene duplication in immune-related gene families for the evolution of longer lifespans in mammals. In dogs, the lack of expanded gene families related to immune function might explain their relatively shorter lifespan compared to other mammals.
Related topics:
Study Uncovers Widespread Dog Behavior Issues Across the U.S.
Dog Owners Warned of Summer Beach Ban in Sunderland
Five Dogs Looking for Their Forever Home
