The secret to why some animals live longer than others might be hidden in their genes. A team of scientists dug into the genetic makeup of various mammals. They wanted to understand how brain size and immune system strength might affect how long an animal lives.

The scientists looked at the longest life recorded for 46 different mammal species. They ignored factors like predators, food shortages, and environmental stress. This way, they could focus on the genetic factors that influence lifespan.

They found that animals with bigger brains and more immune-related genes tend to live longer. For example, dolphins can live up to 39 years, and whales can live up to 100 years. On the other hand, mice with smaller brains rarely live beyond two years. This pattern suggests that smarter animals with stronger immune systems often live longer.

The researchers also discovered that the size of gene families can predict how long an animal might live. They studied 4, 136 gene families and found 236 that were linked to longer lifespans. Most of these gene families were related to the immune system. This shows that a strong immune system is crucial for a longer life.

However, not all animals follow the big brain-long life rule. Mole rats and bats, which have small brains, can also live for many years. Both of these animals have a high number of immune-related genes. This raises an interesting question: Can a strong immune system make up for a smaller brain in extending lifespan?

The immune system plays a big role in helping animals live longer. It fights off infections, gets rid of old cells, and stops tumors from growing. This helps protect the body from the damage caused by aging.

The study also found that genes linked to longer lifespans in humans have higher activity and more alternative splicing. This means a single gene can make multiple proteins, which helps cells respond better to stress and repair damage. This ability might be why some animals live longer.

While immune genes are important, brain size is still a key factor in determining lifespan. Animals with bigger brains, like dolphins and elephants, show more gene activity and expansion. This suggests that smarter animals often live longer.

The researchers also found links between lifespan and genes that repair DNA. Animals that live longer, like whales and elephants, have more of these repair genes. This dual mechanism might help protect cells from damage and keep tissues healthy for a longer time.

The team plans to study cancer-related genes next. They want to see how these genes help some animals live longer and resist cancer. By studying long-lived species, they hope to find genetic targets that could help humans live longer and reduce cancer risk.

In summary, the study shows that longevity in mammals depends on both brain size and immune system strength. Gene family expansions, especially in immune-related genes, suggest that natural selection favors a strong immune system for a longer life. This research could open new paths for aging studies in humans.

How Genes Make Some Animals Live Longer

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