BGI, the world's largest genomic organization, announced that an international team of researchers from Korea, China and the U.S. has, for the first time, demonstrated the physiology1 and longevity2 of the naked mole3 rats (NMR) in terms of genomics and transcriptomics（转录组学） . The results, published online in the journal Nature, provide an excellent opportunity to better understand the unique traits of naked mole rats and advance its use in biological and biomedical studies. With its wrinkled（有皱纹的） skin and double-saber buck4 teeth, the naked mole rat may not be among the most beautiful animals, but they are exceptional in other ways. They are the longest-lived rodent5 known till now and are exceptionally resistant6 to cancer; they can live in full darkness, at low oxygen and high carbon dioxide concentrations; and they are unable to sustain thermogenesis（生热作用） or feel certain types of pain. These unique features make naked mole rats particularly attractive to scientists as emerging models for research on aging and cancer, as well as other biological activities or conditions (e.g. metabolic9 regulation, development, pain and behavior).
In this study, researchers utilized10 the whole-genome shotgun (WGS) sequencing strategy and next-generation sequencing system to sequence the genome of an individual male naked mole rat. The NMR genome is approximately 2.6 Gb, and the predicted NMR gene7 set includes 22,561 genes8. By sequencing the genome, the researchers demonstrated that the ancestor of NMR split from the ancestors of mice and rats about 73 million years ago, and 93% of the NMR genome shows synteny to human, mouse or rat genomes. Utilizing11 comparative transcriptome analysis, some genes related to anti-aging and adaptation to a low oxygen environment were identified based on the different expression levels of NMR transcripts12 between different age groups and at exposure to different levels of oxygen concentration.
The researchers made further investigation13 and found several important genes related to the exceptional traits of NMR. The stable gene expression of TERT and other genes, regardless of age, may be related to NMR's longevity mechanism14. In addition, the unusual regulatory involvement of tumor15 suppressor p16Ink4a and p19Arf may be the key factor in NMR's cancer resistance, and mutation16 in the specificity of HIF1a and VHL may contribute to NMR's high tolerance17 to a low oxygen environment. At least 10% of the approximately 200 genes associated with visual perception in humans and mice were found to be inactivated18 or missing in NMR, implicating19 that NMR's poor visual function may be caused by the deterioration20（恶化，退化） of genes coding for various critical components21 of the visual system.
The genomic information of NMR provides a rich resource for researchers working in aging, cancer, eusociality（真社会制度） and many other areas. The data can be mined in numerous ways to uncover the molecular22 basis for the extraordinary traits of this most unusual mammal. To achieve a more comprehensive insight into NMR's exceptional traits, the international team will continue to explore the molecular mechanisms23 of anti-aging, anti-cancer, adaptation to low oxygen environment and eusociality, with approaches of comparative genomics, comparative transcriptomics, and comparative methylation（甲基化） .
"The NMR genome will play an important role in functional24 studies of NMR, which also will provide unprecedented25 opportunities for exploring some of the most challenging questions in biology and medicine," stated Xiaodong Fang26, Leader of non-model organisms group at BGI and the co-leading author of the study. "We believe that NMR will become a new model in biological and biomedical research in the near future."
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