Genetic engineering can be used to modernize existing biological weapons and to develop genetically altered pathogens, resistant to antibiotics and vaccines. Genetic engineering can produce new kind of weapons based on chemical substances produced naturally by the human body. They could damage the nervous system, the heart, and produce death. For example, peptides are strings of amino acids which perform various functions in our bodies. One important group of peptides is called regulatory peptides, and is activated during times of stress, anger, love, fear, or to fight disease.
Some regulatory peptides affect the central nervous system, and produce heart attacks.
Peptides are regulators of the activity of other molecules, like proteins. Thus, there are peptides with hormonal activity, others with antibiotic activity. Genetic engineering has found a way to duplicate in the lab the genes for certain regulatory peptides, with known toxic properties. One of these, when present in large quantities, is capable of damaging the myelin sheaths protecting the thousands of nerve fibers that transmit electric signals from the brain and spinal cord to the rest of the body. Genetic engineering synthesizes the genes that code for the production of myelin toxin, reproduce them artificially in the lab, and insert them into bacterial cells.