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Denaturation Mapping is a form of optical mapping, first described in 1966. It is used to characterize DNA molecules without the need for amplification or sequencing . It is based on the differences between the melting temperatures of AT-rich and GC-rich regions. [ 1 ]
The process of DNA denaturation can be used to analyze some aspects of DNA. Because cytosine / guanine base-pairing is generally stronger than adenine / thymine base-pairing, the amount of cytosine and guanine in a genome is called its GC-content and can be estimated by measuring the temperature at which the genomic DNA melts. [ 2 ]
In biochemistry, denaturation is a process in which proteins or nucleic acids lose folded structure present in their native state due to various factors, including application of some external stress or compound, such as a strong acid or base, a concentrated inorganic salt, an organic solvent (e.g., alcohol or chloroform), agitation and radiation, or heat. [3]
The process of denaturation on a denaturing gel is very sharp: "Rather than partially melting in a continuous zipper-like manner, most fragments melt in a step-wise process. Discrete portions or domains of the fragment suddenly become single-stranded within a very narrow range of denaturing conditions" (Helms, 1990).
The hyperchromic effect is the striking increase in absorbance of DNA upon denaturation. The two strands of DNA are bound together mainly by the stacking interactions, hydrogen bonds and hydrophobic effect between the complementary bases. The hydrogen bond limits the resonance of the aromatic ring so the absorbance of the sample is limited as well.
This first step is followed by a step of denaturation–renaturation to create hetero- and homoduplexes from the two allele populations in the PCR. To find a homozygous polymorphism, proceed in the same way by premixing a DNA wild population to a population of polymorphic DNA to obtain heteroduplexes after the denaturation–renaturation step.
The tag allows any DNA fragments containing complementary sequences with the DNA probe sequence to be visualized within the Southern blot. [1] The Southern blotting combines the transfer of electrophoresis-separated DNA fragments to a filter membrane in a process called blotting, and the subsequent fragment detection by probe hybridization. [2]
In the less extensive technique of equilibrium unfolding, the fractions of folded and unfolded molecules (denoted as and , respectively) are measured as the solution conditions are gradually changed from those favoring the native state to those favoring the unfolded state, e.g., by adding a denaturant such as guanidinium hydrochloride or urea.