jYCaMP1 is a genetically encoded fluorescent Ca[2+] indicator. It was generated by introducing mutations into jGCaMP7b that convert the circularly permuted green fluorescent protein part of the sensor into a circularly permuted yellow fluorescent protein; jYCaMP1 contains the mutations M65T, V115Y, S117P, K118V, F203L, T222G, V225L, S229A, I250A relative to jGCaMP7b (FBrf0246952).