Recent research has found a connection between expansions in immune-related genes and brain size and the significant differences in lifespan among mammals. Scientists have been puzzled for a long time about why some mammals live much longer than others. While humans can live over a century, certain whales can surpass two centuries, and elephants can easily live for decades, some small mammals like mice or shrews only survive for a couple of years. A new study sheds light on this evolutionary mystery by suggesting that the secret to these differences may lie within the genes of mammals.
An international team of researchers, led by Dr. Benjamin Padilla-Morales from the Milner Centre for Evolution at the University of Bath, discovered that the maximum lifespan potential (MLSP) within a species is closely linked to expansions in gene families associated with the immune system and brain size. The study, which examined genomes from 46 mammal species including whales, bats, dolphins, and mole rats, revealed that species with longer lifespans consistently showed significant expansions in gene families related to immune functions.
The immune system plays a crucial role in managing aging by removing damaged cells, controlling infections, and preventing tumors. These genetic expansions not only enhance disease resistance but also play a key role in protecting mammals against age-related decline. For example, bats, with their small brains, live unusually long, healthy lives due to notable expansions in immune-related genes. Similarly, mole rats, known for defying normal lifespan expectations, show immune gene expansions that contribute to their longevity.
In addition to immune genes, the researchers also confirmed that brain size relative to body mass is significantly correlated with longer lifespans. Mammals with larger brains, such as whales and dolphins, tend to have longer lifespans. This study highlights the importance of both immune system resilience and brain size in the evolution of mammalian longevity.
Brain size and longevity are often closely linked, with some species living over a century thanks to their larger brains. However, this connection is not universal, as certain animals with smaller brains can still enjoy long lives due to immune genetic factors. This suggests that brain size and immune strength have evolved together, providing complementary strategies to enhance longevity.
Dr. Padilla-Morales explains that bigger-brained species do not just live longer due to ecological reasons; their genomes also show expansions in genes related to survival and maintenance. Brain size and immune resilience seem to have evolved hand-in-hand towards longer lifespans.
Previous research has identified individual genes like TP53 in elephants and DNA repair genes in whales that affect lifespan. However, this study focuses on broader genomic trends, highlighting the importance of large-scale changes in gene family sizes in evolution towards longevity.
Long-lived mammals often have expanded gene families responsible for repairing DNA, regulating cell cycles, and managing oxidative stress. These expansions enhance cellular integrity, reducing the risk of aging-related diseases.
Gene duplication events play a significant role in driving these expansions, leading to increased biological complexity and adaptability in organisms, key factors in extending lifespan.
The researchers plan to further investigate cancer-related genes discovered in their study to better understand how these genes impact longevity and why lifespans vary among mammals. This knowledge could potentially lead to advancements in human medicine, especially in treating diseases associated with aging.
The comprehensive genome-wide analysis conducted by the team integrates previous studies and factors like body size, brain size, and population dynamics to provide a clearer understanding of the genetic basis of longevity.
This study emphasizes the importance of gene family expansions in shaping mammalian lifespans and could have implications for future health interventions. It not only aids in understanding evolutionary history but also has the potential to transform approaches to preventing and treating aging-related diseases.
Dr. Padilla-Morales highlights the role of immune system in promoting longevity through genomic changes, including gene duplications and expansions. This insight suggests promising opportunities for further research and potential advancements in human longevity. Continued scientific exploration could lead to innovative strategies for prolonging life and improving overall health in older individuals. The study’s details are published in the journal Scientific Reports. For more positive news stories like this, sign up for The Brighter Side of News newsletter.
