'Gengineering' is the practice of manipulating genes to produce desired changes in an organism. Genetic information, encoded in the molecule DNA, tells a growing organism's cells what proteins to make when, which determines the organism's structure. In 2155, the the genomes of humans and many other plants and animals have been thoroughly mapped. More importantly, the protein-coding functions and synergistic relationships of many genes are understood, though not all.
This involves engineering reproductive cells (seeds in plants, eggs and sperm in animals) to alter, remove, or insert selected genes. In a human or other higher animal, the alterations mean the organism will be born with traits it would not otherwise have had. Its genetic heritage - its germ line - is changed. If it reproduces esxually, it passes on some of its new gengineered traits to children; if it is cloned, it passes on all of them.
Since the 2060s, nanotechnology has brought about a revolution in genetic engineering, permitting the precise creation of designer organisms. Nanomachines similar in concept to retroviruses (hence sometimes called 'nanoviruses') are the main tools of gengineering. They pass harmlessly through cell membranes, can hijack cellular machinery using artificial enzymes, and can carry and insert genetic material. They communicate with each other via enzymes to coordinate their operations. Nanoviruses perform two main types of germline gengineering:
Eugenic gengineering, or eugeneering, involves carefully selecting gene sequences already present within a species' genome, but which vary from individual to individual. These might include genes governing simple traits like eye color, or those leaving someone more or less susceptible to a particular disease. Gene combinations also code for various proteins that affect brain chemistry, having subtle impacts on less tangible traits such as intelligence and behavior. Through selecting combinations of genes known to influence specific traits, gengineers can create much the same effect as centuries of animal breeding, but in a single generation. In 2155, eugeneering aimed at fixing perceived faults (such as poor eyesight or mental instability) is known as 'genefixing'. Engineering whose goal is a better-than-average individual is known as 'genetic enhancement' and the product as a 'genetic upgrade'.
Species modification is more radical, but sometimes easier due to its less subtle nature. As DNA is a universal code, genes from one species can be added to another, producing transgenic life forms with traits from multiple species. Early 21st-century examples of transgenic entities included bacteria modified with human genes to produce human insulin for diabetics, and crops engineered for greater resistance to pests. 2155-era species engineering can do far more, blending genes from multiple species to produce complex transgenic life forms such as water-breathing humans or talking dogs.
This is the new frontier of genetic engineering. Neogenesis involves the creation of original life forms. A step up from cut-and-paste species engineering, it has so far brought forth several simple creations morphologically quite distinct from existing species. In addition to various forms of bionanomachines and industrial bacteria, these include exotics such as living bath mats, clothing, and even buildings. Neogenesis gengineers are studying Europan vent life and Titanian organic chemistry in the hope of discovering unique insights into the creation of life.
Genetic engineering works on reproductive cells. It is possible to alter the genetics of someone who has already developed, but quite tricky, as many gene combinations have already expressed themselves by creating the parts their DNA told them to build, and then shut themselves off.
A proteus nanovirus is a bionanomachine that can take control of already-differentiated cells. At present, a proteus is limited to making 'soft' changes, affecting skin cells, blood cells, genetic material, or the production of specific proteins, rather than 'hard' changes that involve reshaping existing organ, muscle, or bone. However, there are rumors of so-called 'metamorphosis viruses' under development that can produce more extensive transformations, literally rebuilding a person.
Normal proteus nanoviruses can only survive in controlled conditions and must be tailored for a particular subject. However, some nanoviruses capable of general application, and even spreading through contagion, have been developed. Most are either very simple (e.g., skin color) or quite unsafe, often making people sick or worse in the process of changing them. Some military nanoviruses are designed to cause massive cell death, or afflict subjects with blindness, sterility, or a 'hereditary' disease. The most frightening use the majority of people as carriers, spreading harmlessly until they find someone with certain genetic markers, and then striking.
It is possible to acquire symbiotic 'active shield' nano to ward against nano attack, but so far only people in exposed positions (soldiers, those especially at risk to terrorists, etc.) routinely use such technology.
A more benign use of proteus nanotechnology is for full-body cellular regeneration. This process is still fairly new, expensive, and risky, but it can repair nearly any injury or restore the infirm to vigorous youth.