An IRES-Cre and frt-flanked neo cassette were inserted in the 3' UTR to allow bicistronic expression of Myf6 and Cre. Myf6tm1(cre)Mrc was generated from this allele. Reduced transcript expression was confirmed by semi-quantitative RT-PCR at E12.5. This allele is a hypomorph. (J:93444)