Molecular Methods

Abstract

Study of the molecular structure of human chromosomes began in 1869, when Miescher first described “nuclein” extracted from the nuclei of pus cells. Miescher’s description of the new substance lacked biochemical resolution, but the discovery that “nuclein” was found to be universally present in nuclei from a variety of sources led to speculation, even before the turn of the century, that nucleic acid might be the bearer of genetic information (Sturtevant, 1965). Biochemists have been working steadily ever since to discover the molecular components and architecture of chromosomes. The work proceeded relatively slowly until the explosive growth of molecular genetics in the 1970s suddenly provided a kit of tools for disassembling DNA into small fragments and then replicating (cloning) the fragments to yield enough material for chemical analysis down to the level of nucleotide sequence. Thanks to these techniques, new information on the molecular structure of chromosomes now flows so rapidly that no one can keep up with it. This chapter describes some of the most important molecular methods used in studying chromosome structure and function. The literature on molecular methodology is growing even more rapidly than the literature on chromosome structure. Useful reviews can be found in Alberts et al. (1989), Darnell et al. (1990), Freifelder (1987), and a variety of “how to” manuals (e.g., Ausubel et al., 1991; Buckler and Housman, 1991; Wu et al., 1989; Zyskind and Bernstein, 1992).