Figure 6

Example library. These probes are to be printed by a 48-pin print-head, with the pins arranged in a 4 × 12 configuration. The library consists of 14 independent exogenous controls (orange) and 14,592 transcript-specific probes (green). Since the exogenous controls must be printed by all pins, these must be arranged in 4 × 12 blocks of 48 wells. Conversely, the 14,592 target probes only need to be randomly distributed, to facilitate printing once per meta-grid and to ameliorate systematic biases [18]. Source visit number and hence print order are indicated in the figure.