Scientists from the University of Liverpool and the Genome Analysis Centre, while working with other scientists from across the globe, produced the first whole-genome sequence information on the naked mole-rat, an animal known for its longevity and resistance to cancer.
The naked mole-rat, Heterocephalus Glaber, is a rodent from East Africa. They live in colonies in an underground burrow system that has resulted in a number of adaptations. Adaptations include low metabolic rates, the lack of reaction to pain in the skin, and an inability to regulate body temperature because of the stable underground temperatures.
These adaptations are not the reason scientists chose to study the genome of the rodent though. Naked mole-rats are small creatures, only 8 to 10 cm long, which normally means they would live for up to five years like other rodents of that size; however, Heterocephalus can live up to 30 years.
By sequencing the genome of the naked mole-rat, scientists hope to discover the reason behind the rodent’s longevity and resistance to disease associated with aging. Specifically, researchers will study DNA repair and the genes related to the age-resistant processes.
Dr. Joao Magalhaes of the University of Liverpool stated, “The naked mole-rat has fascinated scientists for many years, but it wasn’t until a few years ago that we discovered that it could live for such a long period of time. It is not much bigger than a mouse, which normally lives up to four years, and yet this particular underground rodent lives for three decades in good health. It is an interesting example of how much we still have to learn about the mechanisms of aging.”
Researchers hope to apply the information they learn from the rodent’s genome to human biology. There has never been a recorded case of cancer in a naked mole-rat and recently, studies have found that the animal may even have anti-tumor capabilities not found in humans or other rodents. With cancer accounting for 7.6 million deaths worldwide in 2008 and even more diagnoses, scientists are looking to the naked mole-rat for answers.
“We aim to use the naked mole-rat genome to understand the level of resistance it has to disease, particularly cancer, as this might give us more clues as to why some animals and humans are more prone to disease than others. With this work, we want to establish the naked mole-rat as the first model of resistance to chronic diseases of aging,” said Magalhaes.
To map the genome, researchers used the latest technology. Advances in the technology allowed for a generation of the first draft within a few days.
This technology can best be described as chemical “scissors” that would cut out long strands of DNA code. The shorter codes are read and pieced back together to produce the genome.
According to the Head of Bioinformatics at the Genome Analysis Centre, Dr. Mario Caccamo, the speed at which the genome was sequenced “is a great achievement considering that this is a mammalian species with typically complex and repetitive genome.”
The first draft of the genome is available online for other scientists to use in their research. Researchers can download and use the data for certain small-scale analysis without contacting the discoverers. Soon, the data will be available for use with large-scale analysis in collaboration with the Genome Analysis Centre.
Another database was launched before the data for the naked mole-rat became available. This database, considered the most extensive and complete record, contains information about more than 4,000 animal species. It has information such as lifespan, weight, litter size, and sexual maturity, which can be used to compare animals against one another.
Scientists will be able to study the genome of the naked mole-rat in comparison to other rodents and mammals using this database.
Photo credit: research.gov/common/images/PublicAffairs/17022_Naked_Mole_Rat–rgov-800width.jpg