Genetic complementation
When two DNA molecules that are in the same cell together produce a function that neither DNA molecule can supply on its own. a.k.a. complementation.
Genetic drift
Change in allele frequency from one generation to another within a population, due to the sampling of finite numbers of genes that is inevitable in all real (finite) populations. The smaller the population, the greater is the genetic drift. Sooner or later (depending on the size of the population), genetic drift results in loss of alleles from a population, and hence leads to a loss of genetic variation. Because of this, the minimization of genetic drift is an important consideration for conservation of genetic resources. See genetic diversity.
Genetic engineering
Changes in the genetic constitution of cells (apart from selective breeding) resulting from the introduction or elimination of specific genes through modem molecular biology techniques.


