Phenotype of homozygous Foxf2^W174R pup compared with wildtype.

A, A noticeable difference in gross size can be seen by 3 days of age in mutant pup. B&C, In contrast to the homozygous knockout, the homozygous Foxf2^W174R individuals appear normal at birth, although the amount of milk consumed (arrow) is reduced compared to wildtype littermates.