Production of Eukaryotic Proteins in Bacteria Human insulin, human growth hormone, and other valuable eukaryotic proteins can be produced economically in genetically engineered bacteria.

Expression of Human Growth Hormone in E. coli

Key Points  Valuable proteins that could be isolated from eukaryotes only in small amounts and at great expense can now be produced in large quantities in genetically engineered bacteria.  Proteins such as human insulin and human growth hormone are valuable pharmaceuticals used to treat diabetes and pituitary dwarfism, respectively.

Transgenic Animals Synthetic, modified, or other foreign genes can be introduced into animals and plants, and the resulting transgenic organisms can be used to study the function of the genes, for example, by insertional mutagenesis, to produce novel products, or to serve as animal models for studies of inherited human diseases.

Production of Transgenic Mice by DNA Injection into Eggs

Transgenic Mice Expressing Human Growth Hormone

Reverse Genetics: Dissecting Biological Processes by Inhibiting Gene Expression Reverse genetic approaches make use of known nucleotide sequences to devise procedures for inhibiting the expression of specific genes.

Reverse Genetics  Reverse genetic approaches use the nucleotide sequences of genes to devise procedures for isolating null mutations in them or shutting off their expression.  The function of a gene often can be deduced by studying organisms lacking any functional product of the gene.

Knockout Mice

Production of Gene-targeted Embryonic Stem Cell Technology