Our genes encode all the information that makes us human. The recent sequencing of the human genome, completed in 2003, identified all of the approximately 30,000 genes in human DNA. However, each person has variations in their genetic makeup that account for the diversity in their quality of life. A major focus of genetic research is studying the nature of genetic variation. Single nucleotide polymorphisms (SNPs) are variations in DNA sequences that are the most common molecular mechanisms of genetic variation. Studies show SNPs play a role in the development of various diseases, including depression, cancer, lupus and Alzheimer’s. Stephen Montgomery, who was part of the research team at Canada’s Michael Smith Genome Sciences Centre that sequenced the SARS virus, has been designing and building software to aid in identifying SNPs and other sources of genetic variation that regulate gene expression (the process by which genes are transcribed and translated into proteins). His work on further developing these tools and techniques could improve understanding of the molecular causes of genetic variation, which could suggest new therapies for combating diseases.