Table 8.
Expected Abundance of Classes: Random Markers vs Observed
| Cell Type | No. Codes in the Class | Expected Probability Cell Belongs to Class | Expected No. Cells in Class (of 2596) | Observed No. Cells Among the 2596 |
|---|---|---|---|---|
| AIN1 | 5 | .0012 | 3.2 | 54 |
| AIN2 | 7 | .0049 | 12.8 | 71 |
| AIN3 | 5 | .0129 | 33.6 | 126 |
| DIN1 | 22 | .0047 | 12.2 | 41 |
| DIN2 | 8 | .0014 | 3.5 | 15 |
| DIN3 | 19 | .1139 | 295.6 | 127 |
| DIN4 | 12 | .0941 | 244.3 | 62 |
| DIN5 | 4 | .0106 | 27.4 | 52 |
| DIN6 | 6 | .0524 | 136.0 | 22 |
| EMN1 | 6 | .0194 | 50.3 | 175 |
| EMN2 | 3 | .0471 | 122.2 | 192 |
| EMN3 | 6 | .0195 | 50.7 | 83 |
| EMN4 | 7 | .0556 | 144.3 | 328 |
| IMN1 | 11 | .0349 | 90.7 | 265 |
| IMN2 | 6 | .0566 | 147.0 | 110 |
| IMN3 | 7 | .0296 | 76.8 | 392 |
| IMN4 | 7 | .0555 | 144.1 | 314 |
| Misc | 10 | .1230 | 319.2 | 48 |
| SN1 | 10 | .0008 | 2.1 | 75 |
| SN2 | 3 | .0054 | 14.0 | 44 |
Cells are not randomly distributed between classes. Each of the 20 classes comprised 3–22 codes (164 in total); each code is represented a unique combination of markers. We calculated the theoretic probability for each of the 164 codes by assuming that markers were assorted independently. As shown in Figure 2, the proportions of most codes were very different to those predicted by random assortment. These data were then used to calculate the proportion of each class that would be expected if markers assorted independently (shown above). As can be seen, in 15 of the 20 cases, there were more cells in a class than predicted by random assortment; in the other 5, there were fewer cells. Again, this reinforces that the chemical coding of classes is unlikely to arise from random assortment of markers.
AIN, ascending interneuron; DIN, descending interneuron; EMN, excitatory motor neuron; IMN, inhibitory motor neuron; SN, sensory neuron.