More than one species of the naked mole-rat, a new biomedical model

Modern biomedical research is characterised by a need for new animal models and particularly those from unique or challenging environments and with peculiar characteristics seems to be the most promising. Among mammals, the naked mole-rat Heterocephalus glaber from the Horn of Africa is one of such candidates. Although this small hairless exclusively subterranean rodent has attracted the attention of the scientific community for decades, mainly due to its poikilothermy and eusociality, the exponential trajectory of research started in 21st century with discoveries of its longevity, resistance to cancer and tolerance to pain and hypoxia, in addition to many other intriguing phenomena. The genus Heterocephalus has traditionally been considered to include only a single species, but surprisingly, little is known about genetic differences among its natural populations. Here, we report from mitochondrial and nuclear genomic data across its distributional range, the existence of three species of naked mole-rat, namely: H. glaber, H. ansorgei, and H. philipsi. Among them, H. philipsi stands out as being the most distinct. Its divergence from the rest is 4.1 Ma before the present making it considerably older than most recent mammalian species. The existence of three species that inhabit different environmental conditions, and especially the occurrence of H. philipsi in extremely harsh areas, opens up new horizons for the use of this model in biomedical and other fields of research.