Principle
The core principle behind microarrays is hybridization between two DNA strands, the property of complementary nucleic acid sequences to specifically pair with each other by forming hydrogen bonds between complementary nucleotide base pairs. A high number of complementary base pairs in a nucleotide sequence means tighter non-covalent bonding between the two strands. After washing off of non-specific bonding sequences, only strongly paired strands will remain hybridized. Fluorescently labeled target sequences that bind to a probe sequence generate a signal that depends on the hybridization conditions (such as temperature), and washing after hybridization. Total strength of the signal, from a spot (feature), depends upon the amount of target sample binding to the probes present on that spot. Microarrays use relative quantization in which the intensity of a feature is compared to the intensity of the same feature under a different condition, and the identity of the feature is known by its position.
Read more about this topic: DNA Microarray
Famous quotes containing the word principle:
“The only principle that does not inhibit progress is: anything goes.”
—Paul Feyerabend (1924–1994)
“No two men see the world exactly alike, and different temperaments will apply in different ways a principle that they both acknowledge. The same man will, indeed, often see and judge the same things differently on different occasions: early convictions must give way to more mature ones. Nevertheless, may not the opinions that a man holds and expresses withstand all trials, if he only remains true to himself and others?”
—Johann Wolfgang Von Goethe (1749–1832)
“Experimental work provides the strongest evidence for scientific realism. This is not because we test hypotheses about entities. It is because entities that in principle cannot be ‘observed’ are manipulated to produce a new phenomena
[sic] and to investigate other aspects of nature.”
—Ian Hacking (b. 1936)