Assignment of the gene for the β subunit of thyroid-stimulating hormone to the short arm of human chromosome 1

The chromosomal locations of the genes for the β subunit of human thyroid-stimulating hormone (TSH) and the glycoprotein hormone α subunit have been determined by restriction enzyme analysis of DNA extracted from rodent-human somatic cell hybrids. Human chorionic gonadotropin (CG) α-subunit cDNA and a cloned 0.9-kilobase (kb) fragment of the human TSH β-subunit gene were used as hybridization probes in the analysis of Southern blots of DNA extracted from rodent-human hybrid clones. Analysis of the segregation of 5- and 10-kb EcoRI fragments hybridizing to CG α-subunit cDNA confirmed the previous assignment of this gene to chromosome 6. Analysis of the patterns of segregation of a 2.3-kb EcoRI fragment containing human TSH β-subunit sequences permitted the assignment of the TSH β-subunit gene to human chromosome 1. The subregional assignment of TSH β subunit to chromosome 1p22 was made possible by the additional analysis of a set of hybrids containing partially overlapping segments of this chromosome. Human TSH β subunit is not syntenic with genes encoding the β subunits of CG, luteinizing hormone, or follicle-stimulating hormone and is assigned to a conserved linkage group that also contains the structural genes for the β subunit of nerve growth factor (NGFB) and the proto-oncogene N-ras (NRAS).