Developmental organization of sensory and sympathetic ganglia

(a) Models and predicted contour plots of possible cases whereby MVs are shared between ganglia along the rostrocaudal axis but restricted dorsoventrally (case 1, left) or shared the dorsoventral axis while restricted rostrocaudally (case 2, right). Axes: normalized AF difference between rostral and caudal against that between DRG and SG. In case 1, most MVs deviate from the center along the x-axis but cluster at the center of the y-axis because MVs are shared among rostral and caudal levels. In case 2, most MVs cluster around the center at the x-axis but not the y-axis since clones are more frequently shared dorsoventrally between DRG and SG, but not between different levels. Clones with genomic similarity are colored similarly. (b-c) MV contour plots observed from ID07 (b) and ID08 (c) thoracic levels with the normalized difference in AFs between rostral (defined as T1-T6 levels) and caudal (defined as T7-T12 levels) (y-axis) vs. normalized difference between the DRG and SG (x-axis). Green dots: individual MVs. Blue contours: kernel density estimation of MV distributions. Grey curves: kernel density estimation along the respective axes. Data for the left-sided or right-sided ganglia are plotted separately. (d-e) Comparison of the prevailing model of trunk NC development and the proposed model based on findings from this study. In the prevailing model (d), delaminated NC cells are multipotent, giving rise to both DRG and SG (blue, dark green, and light green cells). The NC cells do not migrate rostrocaudally until reaching the SG, while cells of the DRG do not migrate across different levels. In our proposed model (e), most NC cells are cell fate-specified (red, cyan, and yellow cells) but a minority of NC cells are multipotent (dark blue cells). NC cells migrate rostrocaudally and take up contralateral positions prior to delamination, thereby distributing descendant cells across multiple levels but mostly exclusive to either DRG or SG lineage.