High-Throughput, Motility-Based Sorter for Microswimmers and Gene Discovery Platform*

Animal motility varies with genotype, disease progression, aging, and environmental conditions. In many studies, it is desirable to carry out high throughput motility-based sorting to isolate rare animals for, among other things, forward genetic screens to identify genetic pathways that regulate phenotypes of interest. Many commonly used screening processes are labor-intensive, lack sensitivity, and require extensive investigator training. Here, we describe a sensitive, high throughput, automated, motility-based method for sorting nematodes. Our method was implemented in a simple microfluidic device capable of sorting many thousands of animals per hour per module, and is amenable to parallelism. The device successfully enriched for known \textit{C. elegans} motility mutants. Furthermore, using this device, we isolated low-abundance mutants capable of suppressing the somnogenic effects of the \textit{flp-13} gene, which regulates sleep-like quiescence in \textit{C. elegans}. Subsequent genomic sequencing led to the identification of a \textit{flp-13}-suppressor gene.