The human tropomyosin 3 (TPM3) gene was previously localized to chromosome 1. The non-muscle isoform of the TPM3 gene product becomes fused to a gene product from the tyrosine kinase receptor gene (NTRK1), previously localized to 1q23-->q24, to generate an active oncogene. Two sequence tagged sites spanning three exons and two introns in the carboxy coding region of the gene were used to localize TPM3 to 1q22-->q23 by fluorescence in situ hybridization. This localization now places the NTRK1 and TPM3 genes in close proximity, so that a gene fusion rearrangement would not be cytologically detected. The 1q22-->q23 localization of TPM3 is within the NEM1 locus associated with autosomal dominant nemaline myopathy, making TPM3 a candidate for this disorder.