Abstract
This first lesson will begin with a reminder of the fundamental principles of the evo-devo discipline, with a historical aspect touching on the importance of DNA as a potential source of evolutionary variation. Next, the " locus T ", and its importance in the development of mammalian molecular genetics, will be presented, also historically, before arriving at the cloning of the central gene of this locus, the Tbxt (or T or Brachyuria) gene.
