The DNA molecule is the source of the genetic information that we seek. Series of nucleotides form genes.
Genes are operational units that occupy physical locations within DNA molecules.
Some genes code for proteins and some genes regulate other genes. A variety of techniques can be used to acquire genetic information from the DNA molecule. Genetic information can be valuable by itself or it can provide the necessary control for analyses of other variables. Genetic information can be acquired from the target species as well as from other organisms with which the target species interacts, e.g., parasites, plants, prey, etc. DNA generally is not identical among all individuals in a population.