Abstract: Disclosed are materials and methods for creating customizable traits in animals. In the demonstration of the principle of the subject invention, a keratin-14 specific promoter is used with, red fluorescent protein in the loxp cassette, dominant black (?G23) beta defensin 103 in the pigment cassette, and an SV40 (with intron) polyadenylation sequence. When Cre recombinase (or HTNCre) is applied to the animal's skin in a carrier base (e.g., lipid bilayers), fur is permanently genetically modified to turn black in the shape in which it was applied.

Abstract: The present invention provides highly advantageous and efficient methods for spermatogonial stem cell (SSC) transfer for the generation of animals having valuable traits or genetic background.