C. briggsae strain. Reduced fecundity at 20°C and 25°C. Generated by CRISPR/Cas9 in AF16 background, prg-1(how21) is a 5 bp deletion located 47 bp downstream of the start codon that causes frameshift. prg-1(how21) is presumed null; consistent with previous findings that the stability of piRNAs and Piwi protein are co-dependent in C. elegans, the overall abundance of 21 U-RNAs in Cbr-prg-1(how21) was reduced to ~1% of wild-type. Reference: Pastore B, et al. RNA Biol. 2022 Jan;19(1):1276-1292. doi: 10.1080/15476286.2022.2149170.