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:
“Circumstances ... give in reality to every political principle its distinguishing colour and discriminating effect. The circumstances are what render every civil and political scheme beneficial or noxious to mankind.”
—Edmund Burke (1729–1797)
“Life is a game in which the rules are constantly changing; nothing spoils a game more than those who take it seriously. Adultery? Phooey! You should never subjugate yourself to another nor seek the subjugation of someone else to yourself. If you follow that Crispian principle you will be able to say “Phooey,” too, instead of reaching for your gun when you fancy yourself betrayed.”
—Quentin Crisp (b. 1908)
“Why does philosophy use concepts and why does faith use symbols if both try to express the same ultimate? The answer, of course, is that the relation to the ultimate is not the same in each case. The philosophical relation is in principle a detached description of the basic structure in which the ultimate manifests itself. The relation of faith is in principle an involved expression of concern about the meaning of the ultimate for the faithful.”
—Paul Tillich (1886–1965)