Genetic Engineering Terminology

Agarose: a polymer from seaweed or red algae, used to make the matrix for DNA gels

Clones: genetically identical individuals (for organisms, just like the parent) or DNA molecules.

Cystic Fibrosis: a disease caused by mutation of a chloride channel gene, CFTR, cloned by reverse genetics (see below) and long believed to be a viable target for gene therapy.

Gel Electrophoresis: a method to separate DNA molecules by size, generally using an agarose gel and electrical current. The negatively charged DNA molecules migrate toward the positive pole through a gel matrix.

Gene Therapy: the transfer of 'healthy' genes into an organism to cure a disease caused by a particular mutant allele. Stable delivery of expressed genes to the right cells and avoidance of harmful side effects are key challenges for development of such therapies, but some clinical trials (particularly for eye defects) are very promising.

Germline: cells which contribute their genetic material to the formation of gametes (and ultimately the next generation).

Ligase: an enyzme which can 'splice' together DNA molecules for cloning purposes. Successful ligation reactions are very important for recombinant DNA (see below) technologies.

Plasmid: a circular DNA molecule from bacteria, which can be used to clone and carry foreign genes.

Recombinant DNA: DNA molecules created in a laboratory by combining two or more genetic elements (aka molecular cloning, for example, to make a plasmid DNA carrying a gene of interest).

Restriction Endonuclease: an enzyme that cuts DNA a specific recognition sites (usually palindromes, in other words, with the same DNA sequence if read 5' to 3' on either strand.  GAATTC, for instance). They get their name from the idea that they protect bacteria from foreign genetic elements (i.e. they 'restrict' the replication of viruses like bacteriophage). Cut DNA molecules are said to be 'digested' by these enzymes, and they have been very useful for molecular biology techniques of cloning genes.

Reverse genetics: identification of a normal gene function based on DNA sequences and their position in the genome (in contrast to classical genetics, which starts with the mutant phenotype). Cystic fibrosis was the first genetic disorder in humans understood via such techniques, which allowed the cloning of the CFTR gene by a Canadian group in 1989.

Somatic: cells which make up the body of an organism. Genetic changes in these cells well not be inherited by offspring.

Transformation: inducing the uptake of foreign DNA into a cell or organism (i.e. to get plasmids into bacteria).

Transgene: A foreign DNA introduced into a higher organism.

Transgenic organism: An organism carrying a gene (or genes) from a different species.

Vector: a viral or plasmid DNA or even infectious viral particles used to carry cloned genes, often for insertion into other organisms. Used to create transgenes or allow gene therapy.