We examined
cnd-1p::mCherry expression in early L1 larvae, within an hour of hatching, counting nuclei in the retrovesicular ganglion and also the ventral nerve cord. The retrovesicular ganglion is a linear cluster of cells located on the ventral midline of the worm immediately posterior to the pharynx, and contains the anterior most DA, DB and DD motorneurons (DA1, DB1, DB2 and DD1), along with eight additional cells. Wild type animals showed an average of nine
cnd-1p::mCherry nuclei in the retrovesicular ganglion and 10 in theventral nerve cord (n = 26). As there are 22 motorneurons in early L1 larvae, this suggests that only a subset express the
cnd-1 reporter gene. Based on their location along the ventral nerve cord, co-labeling with
unc-25p::GFP (a known DD neuron marker), and by corroborating against single cell RNA-seq expression data (Packer et al. 2019), we tentatively conclude that
cnd-1p::mCherry is expressed in DA1-5, DB1, DB3, and DD1-6.