1. State Key Laboratory for Agrobiotechnology (M.Z., G.X.), College of Biological Sciences, China Agricultural University, Beijing 100193, People's Repubic of China
2. The Jackson Laboratory (Y.-Q.S., K.W., J.J.E.), Bar Harbor, Maine 04609
3. Laboratory of Applied Genetics (K.S.), Graduate School of Agricultural and Life Sciences, The University of Tokyo, 113-8657 Tokyo, Japan