What is it about?
Analytical ultracentrifugation (AUC) of DNA in CsCl and other salt density gradients at sedimentation equilibrium has remained an elegant way to gain insight into the variation of base composition (GC, guanine + cytosine along animal and plant chromosomes, and into functional correlates of GC. Absorbance profiles of routine preparations of DNA in CsCl are essentially GC histograms of fixed-length sequence fragments (~100 kb). Here, we focused on how absorbance profiles of a species' DNA vary as one changes the scale of one's observation (molecular weight), and dissected this scale-dependence into the contributions from its two main sources (diffusion, sequence effects).
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Why is it important?
AUC enables for a statistical approach to genome analysis; the DNA CsCl profile is equivalent to the frequency histogram of DNA fragments based on high throughput sequences according to their GC content. It is this approach that has allowed the detection of isochores and the numerous functional correlations linked to these structures.
Perspectives
Our understanding of heterogeneous DNA in CsCl gradients can benefit from the comparison of results from AUC and whole-genome sequencing, and the insights gained should prompt more strategic AUC analyses of DNA.
Nicolas Carels
Oswaldo Cruz Foundation
Read the Original
This page is a summary of: Density Gradient Ultracentrifugationand Whole Genome Sequences:Fine-tuning the Correspondence, Springer Science + Business Media,
DOI: 10.1007/2882_009.
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