NOT all small animals lead short lives, and now we know which genes may be behind a remarkable example.
Brandt鈥檚 bat () typically weighs 4 to 8 grams 鈥� about half the weight of a house mouse. At that weight, a well-established link between body mass and lifespan dictates that it should live no more than five years. Yet in 2005, biologists 41 years after it had first been caught.
聯In 2005, biologists captured a bat in Siberia 41 years after it had first been caught聰
Advertisement
Now, analysis of the species鈥� genome suggests an explanation. at Harvard Medical School and his colleagues found key changes to genes in a hormonal system known as the 鈥済rowth hormone/IGF1 axis鈥�. These changes are not seen in other mammals except as rare mutations.
Some are linked to dwarfism in animals and humans, says Gladyshev, and others are linked to ageing. He thinks that as the bat adapted to its insect-eating niche, where small size is an advantage, its genes may have changed to reduce its body size 鈥� and inadvertently increased its lifespan ().
That could be a partial explanation, says at the University of Texas Health Science Center in San Antonio, but would not account for the bat鈥檚 41 year lifespan. In mice, changing the growth hormone axis can extend lifespan by, say, 50 per cent, he adds.
at the University of Maryland in College Park thinks other factors are also at play. For instance, Brandt鈥檚 bats hibernate, which slows down their metabolism and may help prolong lifespan, but some other bats and small animals do not. 鈥淥f course, lifestyle, hibernation, and possibly other factors also contribute to Brandt鈥檚 bats鈥� longevity,鈥� says Gladyshev. 鈥淏ut at the molecular level, the altered growth hormone/IGF1 axis is the strongest lead so far.鈥�
This article appeared in print under the headline 鈥淭he secret of long life that lies in bat genes鈥�
