Make way for the mouse lemur

As these GEITP pages have frequently described, because of the well-established field of mouse genetics (since early 20th-century) and whole-genome sequncing (WGS) of many sublines, mouse research has remained head-and-shoulders above any other animal model, with regard to extrapolation of whole-animal data to humans. The [attached 4-page editorial] suggests that the mouse lemur could become an important animal for genetics research, potentially rivaling the common laboratory mouse Mus musculus — at least for certain questions. Mouse lemurs are primates (the same Order that includes monkeys and apes); therefore, they are more closely related to humans than mice, genetically speaking, yet still have many of the advantages of mice (i.e. small size, rapid reproduction, short generation time, and relatively large litters). As such, they can shed light on some questions about human biology and disease that mice simply cannot (according to this article).

Mouse lemurs exhibit certain aspects of human biology that are not represented in the mouse — from behavior, to disease, to physical traits. Although it is difficult to establish a new model organism, scientists and funding agencies are taking notice of the mouse lemur. Researchers have sequenced the mouse lemur genome (BMC Biol 2017; 15: 110). California Bay Area researchers will soon publish a single-cell Atlas for the primate — a detailed description of gene expression in hundreds of thousands of cells from many different cell-types. After the mouse, this would be the second Cell Atlas published for a mammal. Several labs around the world have already established colonies of mouse lemurs — to explore topics as diverse as Alzheimer disease and evolution.

Dozens of distinctive mouse lemur traits have been identified, many of them medically relevant — such as cardiac arrhythmias, movement disorders, and high serum cholesterol levels. Researchers are now starting the difficult work of connecting these traits to mutations found in the mouse lemur genome, an approach that could reveal the genetic basis of complex primate behaviors and human disease. Mice have provided a huge contribution to biology, but they can only take it so far. Cures for obesity and Alzheimer disease in mice, for example, have never been extrapolated successfully to humans. Mouse lemurs will probably never replace more established primate models such as the macaque, However, more animal models are always better — than fewer animal models.

Among the animal Kingdom, what characteristics should one look for, in developing a new animal model for research? “Time to sexual maturity, litter size, and conservation status” — were considered for the northern tree shrew, the pygmy marmoset, and other prosimian primates, as well as bush babies and the tarsier. But the mouse lemur stood out: it has a gestation time of 2 months, reaches sexual maturity in 6–8 months, and is among the most prolific of all primates, having as many as four offspring per litter. These factors make it possible to study several generations in just a few years. By contrast, the widely used macaque requires about 4 years to reach maturity, is pregnant for 5.5 months, and has only one baby at a time. Large lab colonies show that mouse lemurs can adapt quickly to living in captivity. Besides, they are VERY cute (just check out the photos in the attached article). 😊


Nature 13 June 2o19; 570: 151-154

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