Many labs have worked with Halobacterium salinarum, and they either use the R1 strain or the NRC-1 strain. When the genomes of these two strains were reported in 2008 (Pfeiffer et al.), it showed they are so similar in sequence that they must have derived from the same isolate, but for various reasons it was not possible to identify that isolate. Here we used publicly available sequence data to hunt down the parent. See https://doi.org/10.1002/mbo3.1365. This is not a simple BLASTn comparison but rather a comprehensive analysis and includes a speculative outline of how the two strains ended up as we see them today.