An international team of 36 scientists have transcribed the entire genome of the naked mole rat. The findings were published in the October 12 issue of Nature.
At first glance, naked mole rats seem like odd candidates for a major gene sequencing effort. They are wrinkly, hairless, buck-toothed rodents, about the same size as mice, that live in subterranean colonies in the Horn of Africa. They are one of only two mammalian species that live in colonies like ants or termites, with a single breeding female that suppresses the reproductive maturity of her subordinates. Unlike other mammals, they have difficulty regulating their body temperature. In order to live in their cramped underground tunnels, they have evolved the ability to survive in environments low in oxygen (as little as eight percent compared to 21 percent in the atmosphere) and high in ammonia and carbon dioxide.
The most intriguing features of naked mole rats, however, are their extraordinary longevity, their inability to feel certain types of pain, and their apparent resistance to cancer.
Naked mole rats are extreme survivors. They can live over 30 years, easily making them the longest-living rodents. Even more remarkable, they show no age-related decline in health or fertility. And they appear to be completely resistant to cancer: in a laboratory colony maintained for thirty years, not one malignant tumor has been documented. In another recent experiment, naked mole rats were exposed to doses of a chemical carcinogen 1,000 times stronger than the amount that causes skin cancer in mice. None developed tumors.
This collection of characteristics is why naked mole rats are so attractive to scientists studying aging and disease. The preliminary analysis of the genome has revealed a number of interesting leads. Naked mole rats could be valuable models for scientists looking to prevent tumor growth, slow down age-related diseases or protect the brain from oxygen deprivation during strokes or heart attacks.
Analysis of the genome has revealed the genetic basis for some of the naked mole rat's unusual features. As expected, they lack many genes associated with vision - they don't need it to feel around in the darkness of their underground tunnels. Also gone are genes associated with setting circadian rhythms based on daylight. The researchers found a gene that regulates Substance P, a protein necessary for the perception of certain types of pain, was different in the naked mole rat. They also found changes in genes that may be linked to longevity, body hair, and cancer, which will certainly be the targets of future studies. The information from the genome of these wrinkly almost-blind rodents could some day lead to major advances in medicine.
- Read Science Magazine's coverage of naked mole rat's and their cancer resistance
- Find out more about Naked Mole Rats and their colony at Smithsonian's National Zoo