Sequencing

  1: What is the DNA sequence?
  2: Why do we sequence DNA?
  3: How do we sequence DNA?
  4: What is the assembly?
  5: Why were Genome Centers created?

As we have seen, the genome is made of DNA. The instructions, or genes contained in the genome are thus encoded in chemical form along the DNA molecules. These are formed by the linking of basic units called nucleotides to form a chain. The nucleotides have a variable part, which is chemically a base and can exist in 4 different forms; these forms are symbolized by the letters A,T,G and C. The instructions are thus written in a chemical alphabet of only 4 letters. To represent the succession of bases along the DNA molecule, you can imagine a string of pearls of 4 different colors. It is the order of these bases—their sequence—which constitutes the storage of biological information, in the same way as the succession of magnetic octets permits the storage of information in a computer. In other terms, DNA is the chemical memory of life.