This transgene expresses Cre recombinase under the control of a mouse Kit promoter. In this line, expression of cre was noted in late spermatogenesis, oogenesis and early embryogenesis. Functional analysis of recombinase activity determined that deletion of a floxed reporter gene occurred in a mosaic pattern in all tissues tested. The degree of mosaicism was consistent within an individual, but varied dramatically between individuals. (J:88598)