Outline of C. elegans TILLING procedure. Animals are mutagenised with EMS, picked individually to plates, and allowed to self. One third of the worms are used for DNA and the remaining two thirds are frozen for future analysis. DNA is pooled 8-fold to reduce time and expense. TILLING is performed in order to determine which individuals carry mutations in the gene of interest. Mutations are sequenced and individuals from lines carrying mutations that have an effect on the gene product are thawed and genotyped to isolate heterozygous or homozygous mutants.