(BTBR-at/at × B6-a/a)F1 embryos at E12.5 were dissected in sterile Tyrode's solution, and embryonic skin was divided into dorsal, flank, and ventral pieces, each 1–2 mm2 in size, as shown in Figure 7. Skin fragments were grafted to the testes of congenic animals as follows. After anesthetization with 2.5% Avertin, a 1.5-cm incision in the skin and body wall was made at a point level with the top of the limbs. The fat pads were pulled out and laid on the outside of the body, exposing the testes. Forceps were used to introduce a small hole in the testis capsule through which a piece of dissected embryonic skin was inserted, the testes were then replaced into the abdominal cavity, and the wound was closed in both the body wall and the skin. After 21 days, mice that received grafts were sacrificed and the resulting hair was dissected from the testes and examined.