Region-specific mutagenesis

Scientists Lawriston Wilson and colleagues report results of the largest inversion screen done in mice so far. The strategy relies on the visible, recessive, lethal inversion Rump-white (Rw), which spans approximately50 Mb on proximalchromosome 5. The Rw inversion suppresses recombination in the region, thus acting as a balancer and allowing for the relatively straightforward identification and recovery of N-ethyl-N-nitrosourea (ENU)-induced mutations. 43 mutantswere generated, 37 of which cause embryonic or perinatal lethality.