Human genetic engineering how does it work

Genetic engineering aims to modify the genes to enhance the capabilities of the organism beyond what is normal. Ethical controversy surrounds possible use of the both of these technologies in plants, nonhuman animals, and humans. Particularly with genetic engineering, for instance, one wonders whether it would be proper to tinker with human genes to make people able to outperform the greatest Olympic athletes or much smarter than Einstein.

If genetic engineering is meant in a very broad sense to include any intentional genetic alteration, then it includes gene therapy. Two fundamental kinds of cell are somatic cells and reproductive cells. Most of the cells in our bodies are somatic — cells that make up organs like skin, liver, heart, lungs, etc.

Reproductive cells are sperm cells, egg cells, and cells from very early embryos. Two problems must be confronted when changing genes. The first is what kind of change to make to the gene. The second is how to incorporate that change in all the other cells that are must be changed to achieve a desired effect.

There are several options for what kind of change to make to the gene. Or one could use a chemical to simply turn off a gene and prevent it from acting. There are also several options for how to spread the genetic change to all the cells that need to be changed. If the altered cell is a reproductive cell, then a few such cells could be changed and the change would reach the other somatic cells as those somatic cells were created as the organism develops.

But if the change were made to a somatic cell, changing all the other relevant somatic cells individually like the first would be impractical due to the sheer number of such cells.

The cells of a major organ such as the heart or liver are too numerous to change one-by-one. Instead, to reach such somatic cells a common approach is to use a carrier, or vector, which is a molecule or organism.

A virus, for example, could be used as a vector. The virus would be an innocuous one or changed so as not to cause disease. It would need to be a very specific virus that would infect heart cells, for instance, without infecting and changing all the other cells of the body.

Fat particles and chemicals have also been used as vectors because they can penetrate the cell membrane and move into the cell nucleus with the new genetic material. Gene therapy is often viewed as morally unobjectionable, though caution is urged.

The main arguments in its favor are that it offers the potential to cure some diseases or disorders in those who have the problem and to prevent diseases in those whose genes predisposed them to those problems.

If done on reproductive cells, gene therapy could keep children from carrying such genes for unfavorable genetic diseases and disorders that the children got from their patients. Genetic engineering to enhance organisms has already been used extensively in agriculture, primarily in genetically modified GM crops also known as GMO --genetically modified organisms.

For example, crops and stock animals have been engineered so they are resistant to herbicides and pesticides, which means farmers can then use those chemicals to control weeds and insects on those crops without risking harming those plants. In the future genetic enhancement could be used to create crops with greater yields of nutritional value and selective breeding of farm stock, race horses, and show animals. Genetically engineered bacteria and other microorganisms are currently used to produce human insulin, human growth hormone, a protein used in blood clotting, and other pharmaceuticals, and the number of such compounds could increase in the future.

Enhancing humans is still in the future, but the basic argument in favor of doing so is that it could make life better in significant ways by enhancing certain characteristics of people. We value intelligence, beauty, strength, endurance, and certain personality characteristics and behavioral tendencies, and if these traits were found to be due to a genetic component we could enhance people by giving them such features.

Advocates of genetic engineering point out that many people try to improve themselves in these ways already — by diet, exercise, education, cosmetics, and even plastic surgery. People try to do these things for themselves, and parents try to provide these things for their children.

If exercising to improve strength, agility, and overall fitness is a worthwhile goal, and if someone is praised for pursuing education to increase their mental capabilities, then why would it not be worthwhile to accomplish this through genetics? Advocates of genetic engineering also see enhancement as a matter of basic reproductive freedom.

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The increased muscle is due to the fact that these animals have a mutation in a specific gene that normally is involved in muscular hypertrophy.

A deletion in the bovine myostatin gene cuases the double-mustard phenotype in cattle. Nature Genetics 17, 71 Traditionally, humans have manipulated genomes indirectly by controlling breeding and selecting offspring with desired traits.

Genetic engineering involves the direct manipulation of one or more genes. Most often, a gene from another species is added to an organism's genome to give it a desired phenotype.

Genetic engineering is a term that was first introduced into our language in the s to describe the emerging field of recombinant DNA technology and some of the things that were going on.