The principle of genetic
manipulation from a general point of view is either the integration of foreign genes, plants or animals, into the body
of a member of a different species, or the modification of the genes of an organism to change or optimize a characteristic. Genes are pieces of DNA, carrier of the genetic information which determines all the characteristics of an individual: eye color, size, ability to resist disease
, etc. Manipulations are sometimes made in agriculture on certain crops in order to obtain a larger quantity of production or quality, or to optimize a breeding race to remove more milk for example, or more tasty meat. In humans, genetic manipulations are not allowed.