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Sample A: Cover Page of Thesis, Project, or Dissertation Proposal

Sample A: Cover Page of Thesis, Project, or Dissertation Proposal

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demonstrate sub-optimal stability with the desired target [18, 54, 55]. One<br />

such class is that <strong>of</strong> single nucleotide polym<strong>or</strong>phisms. F<strong>or</strong> sh<strong>or</strong>t<br />

oligonucleotide probes (i.e. 25-mers) a single-base mismatch is supposed to<br />

be sufficiently destabilizing that signal decreases markedly [9]. This is by no<br />

means consistently observed, since there is a very large context dependence<br />

[18, 55, 56]. In the equilibrium equations <strong>of</strong> duplex f<strong>or</strong>mation, the duplex<br />

dissociation rate is slower than the single strand association rate, but<br />

mismatches dissociate m<strong>or</strong>e rapidly than perfect matches; again, the<br />

difference in rate constants is dependent on the type and context <strong>of</strong> the<br />

sequence variant [28, 29].<br />

c. Transcript Models. A second class <strong>of</strong> alternate alleles has to do with<br />

transcript splicing. Gene models are routinely redefined as m<strong>or</strong>e evidence is<br />

published [43], while probe designs are based upon a static definition <strong>of</strong> the<br />

gene model at the manufacturing time. This means that probe annotation<br />

must be continually updated by the investigat<strong>or</strong> in <strong>or</strong>der to understand which<br />

probes should be deprecated and which should be selectively combined,<br />

depending on the desired analysis. Unexpected outcomes are common,<br />

including such observations as probes mapping to introns that thereby are<br />

expected to have no signal, some <strong>of</strong> which have high responses, leading to<br />

some doubt about the accuracy <strong>of</strong> the gene model [57].<br />

d. Inaccessible Probes. As discussed above, any single-stranded nucleic acid<br />

can f<strong>or</strong>m stable self complementary structures, due to intramolecular<br />

hydrogen bonding and base stacking [22, 25, 54]. Such structures can<br />

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