MSM/Ms was derived from wild mice trapped in Mishima Prefecture, Japan. This strain has been reported to be resistant to the development of lymphoma, due to at least two loci in crosses involving strain SL/Kh (Pataer et. al., 1996). C3HxMSM F1 hybrids treated with N-methyl-N-nitrosourea (MNU) develop squamous cell carcinomas of the forestomach with about 20% and 15% having mutations in H-ras and p53, respectively (Masui et. al., 1997). Stephan et. al. reported that wild-derived strains, MSM, CZECH (Stock No. 001144) and MOLF (Stock No. 000550), exhibit decreased secretion of TNF in response to stimulation by poly(I:C) (a synthetic analog of double-stranded RNA), the result of a P369L substitution in Tlr3. Response to Tlr2, Tlr4 and Tlr7-agonists is normal. Wild-derived mice are genetically distinct from common laboratory mice for a number of complex phenotypic characteristics and are valuable tools for genetic mapping, evolution and systematics research.
In 2019-2020, researchers at The Jackson Laboratory discovered this inbred strain contains the Trem2S148E allele - a naturally occurring variant at position 48351151-48351152 on Chr 17 (rs108080490 and rs107649577; Ensembl GRCm38.p6). This TC to GA transition results in a serine to glutamic acid substitution at amino acid 148 (S148E).
