Cannabis comes in many varieties, also known as strains. Although there are only two species of cannabis, thousands of strains are believed to exist. Common strain names include OG Kush, Sour Diesel and White Widow.
Different strains can have different effects. What makes strains unique is their genetic profile. Genes determine many characteristics of a plant, including its appearance and cannabinoid levels.
Many patients find certain strains more effective than others. However, marijuana’s legal status has made it difficult for scientists to study and verify the differences between strains.
van Bakel H, Stout JM, Cote AG, Tallon CM, Sharpe AG, Hughes TR, Page JE (2011), The draft genome and transcriptome of Cannabis sativa. Genome Biology, 12:R102. doi:10.1186/gb-2011-12-10-r102