ABSTRACT
A number of significant improvements in the electrophoretic performance and design of DNA sequencing devices have culminated in the introduction of truly industrial grade production scale instruments. These instruments have been the workhorses behind the massive increase in genomic sequencing data available in public and private databases. We highlight the recent progress in aspects of capillary electrophoresis (CE) that has enabled these achievements. In addition, we summarize recent developments in the use of microfabricated devices for DNA sequencing that promise to bring the next leap in productivity.
Subject(s)
Electrophoresis, Capillary/methods , Sequence Analysis, DNA/methodsABSTRACT
A systematic study of the separation of double-stranded DNA in hydroxypropylcellulose (HPC) with a molecular mass of 10(6) was undertaken, using a variety of concentrations (from 0.1 to 1%) and different electric fields (from 6 to 540 V/cm). The data show that at high polymer concentrations ( > or = 0.4%) and low fields, the separation mechanism is similar to that occurring in gels. The results are in good agreement with theoretical models, and in particular with a recently proposed theory for gels with a pore size smaller than the persistence length of DNA. For more dilute solutions and high fields, however, the separation pattern cannot be explained by existing theories. The existence of an original mechanism was confirmed by the direct observation of the conformation of double-stranded DNA molecules in the polymer solution by fluorescence videomicroscopy. Practical conclusions for the capillary electrophoretic separation of duplex DNA are drawn.
Subject(s)
DNA/analysis , Electrophoresis, Capillary , Benzoxazoles , Cellulose/analogs & derivatives , DNA/isolation & purification , Intercalating Agents , Mathematics , Microscopy, Fluorescence , Microscopy, Video , Models, Chemical , Nucleic Acid Conformation , Quinolinium Compounds , SolutionsABSTRACT
DNA solutions subjected to an electric field exhibit an instability that leads to DNA segregation in aggregates tilted with regard to the field. With the use of epifluorescence videomicroscopy, the evolution of DNA patterns in capillaries as a function of DNA concentration, DNA size, field strength, and field frequency was studied. The field threshold for segregation was decreased when the frequency was lowered or when the DNA molecular weight or concentration was increased. Aggregation is attributed to an electrohydrodynamic instability triggered by the dipole-dipole interaction. This phenomenon explains the failure of earlier attempts to separate large DNA in capillaries.
