Genetic manipulation, also called genetic engineering, refers to the alteration of the genes of an organism. It involves manually adding new DNA to an organism to add new traits.
Examples of genetically engineered organisms include plants that are resistant to certain insects, plants that tolerate herbicides and crops with altered oil content. (source)
Double helix is the description of the structure of a DNA molecule. A DNA molecule consists of two strands that wind around each other like a twisted ladderThroughout GATTACA there are several images of the double helix used.