ABSTRACT
In this chapter, the authors consider some aspects of the different techniques now available for the size separation of large DNA molecules, emphasizing methods currently used in our laboratory. They illustrate the use and value of the approach with examples taken from our studies of the bovine major histocompatibility complex (MHC). The hypothesis is that the higher-molecular-weight molecules do this more slowly than low-molecular-weight forms and thus their progress through the gel matrix is relatively delayed. Further evidence of multiple class I gene expression came with the study of gamma-irradiation and chemically induced deletion mutant lymphoblastoid cell lines. However, from this analysis, it was clear that the loss of al-lospecificities in the mutated clones is accompanied by deletion of genetic material or important modifications of the class I region.
