Methods The KM mice were dealed with PMSG and HCG to make them superovulation,afterwords were mated individually with the male mice.

• 方法采用经超量排卵的KM雌鼠与正常615雄鼠交配,取受精卵,分别将单胚卵、双胚卵、桑椹胚和囊胚、移入发情的假孕KM雌鼠的输卵管和子宫中妊娠产仔。