To determine, if LRRK2 could modify the development of tauopathy in vivo, we crossed human WT LRRK2 BAC mice that do not have an overt phenotype or pathological abnormalities (including evidence of tau pathology) [46], with rTg4510 mice that express human mutant (P301L) 0N4R tau [65] to generate mice that expressed both transgenes (LRRK2/TauP301L) (see breeding scheme in Supplemental Fig. 2). This evidence concerns the gene MAPT and tauopathy.