http://identifiers.org/mgd/MGI:1888808 Cdkn1b<tm1Ako> P27- targeted mutation 1, Andrew Koff p27delta p27<Kip1> p27/Kip1<-> Cdkn1b<tm1Kiyo> p27<Kip1 -> MGI:1888808 p27<D51> Null/knockout