After official publication in Bio-protocol (https://bio-protocol.org/e4272), we realized that an error in the Background section occurred during the editorial process, which caused certain text to be duplicated. The published text “Like other stem cells, C. elegans GSCs are kept in a stem-like state by signaling from a somatic niche (the distal tip cell, Kimble and White, 1981; Figure 1A and 1E). Like several types of mammalian stem cells, the size of the C. elegans GSC pool is maintained according to a population model, wherein differentiation due to displacement from the niche is balanced by symmetrical divisions to maintain a relatively constant number of stem cells. according to a population model, wherein differentiation due to displacement from the niche is balanced by symmetrical divisions, thus maintaining a relatively constant number of stem cells (Morrison and Kimble, 2006; Joshi et al., 2010)” has been corrected to “Like other stem cells, C. elegans GSCs are kept in a stem-like state by signaling from a somatic niche (the distal tip cell, Kimble and White, 1981; Figure 1A and 1E). The size of the GSC pool is maintained according to a population model, wherein differentiation due to displacement from the niche is balanced by symmetrical divisions that make more stem cells (Morrison and Kimble, 2006; Joshi et al., 2010).”

This correction is purely textual and does not change the content of the Background section or anything relating to the published procedure.