'Freaky' Mouse Is Immune to Poison

Mice from different countries have likely interbred, producing what researchers call a “freaky” and “superior” house mouse that is resistant to a common rodent poison.

The discovery, reported in the journal Current Biology, demonstrates how hybridization can occur naturally among animals, yielding non-sterile individuals with beneficial attributes. In this case, the result is a mouse that is resistant to warfarin, a toxic and, usually, deadly ingredient in many rodent poisons.

Hybrids often cannot reproduce, but “sometimes there is the occasional odd hybrid that has just about the right novel combination of genomes from two species that renders them, at least temporarily, superior over the pure species,” lead author Michael Kohn told Discovery News.