How to learn new and interesting things from model systems based on “exotic” biological species

The famous quip of Monod that “… anything found to be true of E[scherichia] coli must also be true of elephants” reflects the widely held belief that the attention and resources of researchers are most effectively focused on a few wisely chosen “model systems” (1). Considerations such as short generation times, facility of genetic manipulation, and the economics of husbandry have strongly influenced these choices. The first half of the 20th century, dominated by studies of physiology and biochemistry, saw a relative diversity of model systems. In the modern era, the limitations imposed by the availability of precious molecular resources such as antibodies or gene clones (and until very recently, of whole genome sequences) have keenly sharpened the emphasis on a few “mainstream” model systems. For mammals, in addition to the obvious emphasis on human studies, the mouse has emerged as the premier model. In this issue of PNAS Seluanov et al. (2) study naked mole rats and discover a new cancer resistance mechanism not yet documented in any other mammal. Naked mole rats (Heterocephalus glaber) are not rats at all, but hystricognath rodents more closely related to porcupines and guinea pigs than rats or mice. They are indigenous to east Africa where they lead subterranean lifestyles in extensive tunnel systems. They are almost completely sightless and hairless (Fig. 1 Left), although most other mole rats (there are some 22 species in the family Bathyergidae) are neither blind nor naked. In addition to their extreme adaptation to life underground, they initially attracted attention because of their eusocial behavior, having a single reproductively active “queen” female in a large colony of nonreproductive “workers” (the only other example of eusociality in all of mammalia is another mole rat, albeit a furry one). Naked mole rats and their cells. (Left …