GENETIC-MAPPING OF 40 CDNA CLONES ON THE MOUSE GENOME BY PCR

We recently proposed a new PCR-based genetic marker assay for the mous e genome that exploits sequence differences in the 3'-untranslated reg ion (UTR) of cDNAs between different mouse strains, called ''biallelic polymorphic expressed sequence tags (bESTs).'' The specific use of 3' -UTR has several advantages: (1) frequent sequence polymorphism betwee n different mouse strains, (2) most commonly uninterrupted by introns, (3) usually unique sequence even among closely related gene family me mbers. In this paper, we identify additional genetic loci defined by b EST and determine their location on the mouse genetic map by using int erspecific backcross mapping panels between C57BL/6J and Mus spretus. Of 136 markers tested, 86 produced unique PCR products from C57BL/6J a nd M. spretus genomic DNAs. We then sequenced these 86 PCR products fr om C57BL/6J and M. spretus and found that 59 markers have sequence pol ymorphisms. Of these, we mapped 36 by restriction fragment length poly morphism (RFLP) of the PCR products and 4 by length polymorphism (LP) of the PCR products. We discuss the possibility of a large-scale appli cation of this method for cDNA mapping.