Cahoon, Cori K.Uebel, Celja J.Villeneuve, Anne M.Libuda, Diana E.2023-01-092023-01-092023-01-06Cahoon, CK; Uebel, CJ; Villeneuve, AM; Libuda, DE (2023). Epitope tag-specific differences in the detection of COSA-1 marked crossover sites in C. elegans spermatocytes. microPublication Biology. 10.17912/micropub.biology.000724.https://hdl.handle.net/1794/27913https://doi.org/10.17912/micropub.biology.0007246 jpagesNascent crossover sites in C. elegans meiocytes can be cytologically detected using epitope-tagged versions of the pro-crossover protein COSA-1. In spermatocytes, differences exist between cytologically-detected and genetically-detected double crossover rates. Here, we examine nascent crossovers using both GFP- and OLLAS-tagged COSA-1. Similar to previous work, we find that most late pachytene spermatocytes display 5 COSA-1 foci, indicating one crossover per autosome bivalent. However, we detected more nuclei with >5 COSA-1 foci using OLLAS::COSA-1, reflecting some bivalents having 2 COSA-1 foci. These results demonstrate tag-specific differences in the detection of COSA-1 marked nascent crossovers in spermatocytes.enCreative Commons BY-NC-ND 4.0-USArticle