JCAOligoTutorialDNA

From OpenWetWare
Jump to navigationJump to search
The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.

What is this DNA stuff?

If you've never heard of DNA, first read http://en.wikipedia.org/wiki/Dna and maybe pick up a textbook for the basics.

The critical things you should understand before trying to do this tutorial:

  • DNA is a chemical entity, but we represent its sequence in the computer
  • DNA is made of 4 deoxyribonucleotides, A, T, C, and G (casually called bases) in a specific sequence determined by covalent bonds
  • DNA molecules have directionality, one end is the 5' terminus, the other end is the 3' terminus
  • By convention, DNA sequences are always written out in the 5' to 3' direction unless stated explicitly with "5'-" and "3'-" Alternatively, DNAs can be represented in cartoon form as a line with a barb at one end. The barb refers to the 3' end.
  • DNA can be circular or linear
  • DNA can be single stranded or double standed
  • Double standed DNAs anneal to each other by Watson-Crick base pairing
  • The sequence of the complementary strand of a double standed DNA is the "reverse-complement" of the other strand
  • The "reverse" and "complement" operations on a DNA sequence do not result in biochemically-meaningful sequences. You must always do both (reverse-complement) to get the sequence of the complementary strand
  • With some exceptions, bacterially replicating DNAs are double stranded circular molecules regardless of whether they are genomic DNAs or plasmid DNAs.
  • Even when DNAs are circular double stranded molecules, we represent them as linear single-stranded sequences using our software tools like ApE