These 3 slides were copied from a larger slide set at http://www3.kumc.edu/jcalvet/bioc801b/index.htm
, They are owned by Pr. James P. Calvet at the Department of Biochemistry
and Molecular Biology in the University of Kansas Medical Center.
They are a nice set of slides that you could visit as well, but for our
purposes, these three slides suffice.
This figure shows a
Cot curve for human genomic DNA. This DNA shows complex reassociation
kinetics because it is actually a mixture of three different species or
populations of DNA: fast-reassociating, intermediate-reassociating, and
slow-reassociating fractions. The fast and intermediate fractions
are composed of repeated sequences in the genome, and the slow fraction
is composed of single-copy sequences. Single-copy sequences are those
that are present in one copy per haploid genome. The next slide illustrates
the concept of how sequence complexity affects the rate of DNA reassociation.
The following slide shows estimates for the complexity of each fraction
and how many times each sequence is present in the haploid genome, both
of which are derived from the Cot1/2
of each fraction.
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