AUTOMATION OF MOLECULAR-GENETIC METHODS .1. DNA PURIFICATION, SOUTHERN BLOTTING, AND DNA-SEQUENCING

Molecular genetics is rapidly moving from the research lab into the cl inical lab, The first step in any molecular genetic analysis is purifi cation of the nucleic acids from the sample, Various sample preparatio n methods and automated purification systems are commercially availabl e. All release nucleic acid from the cell and purify it until it is fr ee of substances that interfere with subsequent molecular analysis, Tw o key analysis techniques are discussed in Part 1 of this article, Sou thern blotting and DNA sequencing, Amplification-based analysis is the subject of Part 2 of this article. Automation for Southern blotting h as been divided into two parts-automation of the electrophoretic separ ation of restriction fragments and blotting of those separated fragmen ts onto a support membrane and automation of the detection and interpr etation of signal after probe hybridization. Radioactive DNA sequencin g makes use of many of the same imaging and analysis tools used to det ect bands from Southern blots, Full automation of DNA sequencing invol ves robotic workstations to pipette reagents and run the enzymatic seq uencing reactions and fluorescent DNA sequencers to automate the elect rophoretic separation and detection of fragments and reconstruction of final sequence.