The #1 breakthrough according to Science was the proof of the Poincare conjecture. The runners-up are, in order: (see here for all the relevant pubs)
- Sequencing of Neanderthal autosomal DNA
- The worlds two great ice sheets losing ice to the oceans, at an accelerating pace
- Discovery of a fossil of a fish/amphibian.. "missing link" between water and land dwellers
- Cloaking technology: playing around with optics
- advances in understanding and treating age-related macular degeneration
- genetics of biodiversity and speciation
- new microscopy technology that gives clearer view of cells and proteins.
- the role of long-term potentiation in the formation of memory.
- the discovery of piRNAs, another class of small RNA molecules.
Areas to watch in 2007.
I won't list them all here, but obviously more genetic stuff (including whole genome association studies), and global warming.
Also in this issue of Science is a profile of Bruce Lahn. Check out GNXP on this.