The pink mouse. A) A transgenic mCherry and its wild-type littermate are shown at postnatal day (P)0. B, C) Comparison of the paws of a young-adult wild-type (B) and a transgenic (C) mouse. The pink colored paw of the transgenic mouse is clearly visible without optical instruments. D, E) An adult wild-type mouse with an opened body (D) and its transgenic littermate (E), which displays reddish organs.