Cover
A T-shirt bearing an annotated gene-sequence map of human chromosome 1 symbolizes the Breakthrough of the Year for 2007--the realization that DNA differs from person to person much more than researchers had suspected. This conceptual advance, driven by results from several fields, may transform medicine but could also threaten personal privacy.

Breakthrough of the Year
Equipped with faster, cheaper technologies for sequencing DNA and assessing variation in genomes on scales ranging from one to millions of bases, researchers are finding out how truly different we are from one another.

Combinatorial Synthesis of Peptide Arrays onto a Microchip
A method of electrically directing amino acids one at a time to precise spots on a microchip can be used for combinatorial in situ synthesis of 40,000 peptides per square centimeter.

Grassroots Effort Pays Dividends on Presidential Campaign Trail
The run-up to the 2008 U.S. presidential election campaign -- which kicks off with the Iowa caucuses on 3 January and the New Hampshire primary 5 days later -- has been a coming-out party for climate change.

Trials of NIH's AIDS Vaccine Get a Yellow Light
Last week, the U.S. National Institutes of Health's AIDS Vaccine Research Subcommittee met here to discuss the future of an AIDS vaccine made by NIH after a test of a similar vaccine found that it may have actually increased some people's risk of becoming infected with HIV.

Animal Extremists Get Personal
As animal-rights extremism wanes in the United Kingdom, U.S. researchers have faced increasing threats and harassment.