1. DNA chips

DNA microarrays are made up of DNA fragments, called probes, immobilized on a solid support in an ordered arrangement. The operating principle of these chips is based on a fundamental principle of molecular biology: hybridization, i.e. the pairing of two DNA sequences by base complementarity. By way of analogy, this mechanism can be compared to that of the zipper. Indeed, the strands extracted from the DNA double helix have the ability to spontaneously reform this double helix as soon as they come face to face with the complementary strand; the four elementary molecules of DNA have the particularity of joining two by two: adenine (A) with thymine (T), cytosine (C) with guanine (G). This operation is based on the same principle as Southern blot or Northern blot, which are commonly used to detect and quantify the presence of a specific nucleic sequence within a complex biological sample....