Remapping lab rats
For the first time in nearly 15 years, the rat genetic map has been updated.
Genetic maps help us navigate uncharted data, but to successfully use them to link genes to complex traits, their resolution must be high enough to yield a manageable list of candidate variants. That’s why genetic maps for mice and humans have been routinely updated in recent years as mapping technologies have improved.
However, one important map has lagged: the genetic map for rats had not been updated since 2004. As such, the resolution of that map was 100 times lower than the mouse genetic map. Since rats are such an important experimental organism for understanding disease, Littrell et al. set out to construct a new, high-resolution genetic map for lab rats, which they published in G3: Genes|Genomes|Genetics.
With a nearly 50-fold improvement, the new map has a much higher resolution than the previous one. Additionally, the authors created sex-specific gene maps, which had not previously been available for rats. They also examined some particular features of these new maps, finding that rates of recombination were higher on average in females than in males, which is a phenomenon that occurs in many mammal species.
To make it even more useful, the authors also added other data to the map, including the locations of tens of thousands of SNPs. The hope is that this new view of the rat genome will allow geneticists to more effectively explore genetic modifiers of common diseases.