Five and fewer digits are autopod patterns seen in modern tetrapods, indicating highly conserved regulatory programs in constraining digit number.In early limb bud development, autopod mesenchyme is divided into anterior and posterior populations depending on distinct responses to Shh signal.The posterior mesenchyme growth is terminated by increased distance between Greml-expressing mesenchyme, zone of polarity activity (ZPA) and apical ectodermal ridge (AER), but little is known about how the growth mode of anterior mesenchyme is switched off.