Premetamorphic Xenopus laevis tadpole tail respond to thyroid hormone by resorption. The goal of this experiment is to identify the genes involved in the TH-induced resorption tadpole tail and compare it to TH-induced proliferation and differentiation program in tadpole limb and brain. Xenopus tadpoles (NF54) were treated with 100 nM T3(triioodthyronine) in 0.1 x MMR for another 24h and 48h or without T3 for 48h (control group). NF 61 tadpoles were in 0.1 X MMR till they reached NF stage 62. The tails were dissected after the experiment.