Ever since the discovery of DNA as the molecule responsible for genetics, in particular when it became clear that the ordering of the chemical components in this polymer was the information that DNA stored, scientists have dreamt about determining the full sequence of the human genome. For Francis Crick, who co-discovered the structure of DNA (along with James Watson, using data from Rosalind Franklin) this would be the final step towards unifying life and chemistry: demystifying the remarkable process that leads to us and all other living creatures. Back in 1953 this was a fantasy, but slowly and steadily over the ensuing decades it became a reality.
C. elegans: an elegant genome
On the second day of christmas, my true love sent to me: The C. elegans (worm) genome. The lowly nematode worm is probably the “newest” widespread model organism, developed by Sydney Brenner and colleagues in the 1960s at the Laboratory for Molecular Biology (LMB) in Cambridge as something between the complexity of fly and the simplicity of yeast.
It was an inspired choice: you could keep the worm in the laboratory easily (it eats a lawn of bacteria, very often E. coli), and setting up crosses was easy and remarkably (and this shows how lucky Sydney is), it has completely stereotypical development. Every adult C. elegans worm has an identical number of cells (John Sulston was one of the key people to work this out who would later lead the worm and genome project). It is as if every cell has a name, with one tree providing the single way of going from a genome to a collection of cells.