Breathing is a genetically determined behavior generated by neurons in the brainstem. Transcription factors, in part, determine the basic developmental identity of neurons, but the relationships between these genes and the neural populations generating and modulating respiration are unclear. The diversity of brainstem populations has been proposed to result from a combinatorial code of transcription factor expression corresponding to the anterior-posterior (A-P) and dorsal-ventral (D-V) location of a neurons birth. I provide a schematic of transcription factor coding identifying at least 15 genetically distinct, D-V subdivisions of brainstem neurons that, combined with A-P patterning, may provide a genetic organization of the brainstem in general, with the eventual goal of describing respiratory populations in particular. Using a combination of fate mapping in transgenic mouse lines and immunohistochemistry, we confirm the parabrachial nuclei are derived from a subset of Atoh1 expression progenitor neurons. I hypothesize the Kolliker-Fuse nucleus can be uniquely defined in the neonate mouse by the co-expression of the transcription factor FoxP2 in Atoh1 derived neurons of rhombomere 1.