Is it possible to genetically engineer a human
To me, genetic engineering, broadly defined, means that you are taking pieces of DNA and combining them with other pieces of DNA. And then taking what you have engineered and propagating that in any number of different organisms that range from bacterial cells to yeast cells, to plants and animals.
So while there isn't a precise definition of genetic engineering, I think it more defines an entire field of recombinant DNA technology, genomics, and genetics in the s. David M. At this point, further penalties seem to be in the hands of the police. There are a range of criminal charges that He could face. He also stipulated that participants would have to repay costs if they dropped out. Liu Ye, a lawyer at the Shanghai Haishang Law Firm, says that if such payments are found to count as coercive measures, they could constitute a crime.
Guangdong province also found that He used forged ethics-review documents during recruitment of participants and swapped blood samples to skirt laws against allowing people with HIV to use assisted reproductive technologies. Why were scientists silent over gene-edited babies? But He might have inadvertently caused mutations in other parts of the genome, which could have unpredictable health consequences.
He claims to have found no such mutations. Also, CCR5 is thought to help people fight off the effects of various other infections, such as West Nile virus. If the gene is disabled, the girls could be vulnerable. But identifying those health effects could take years. He promised to follow up with the girls until they were 18 years old, but it is unlikely that the health ministry, which ordered He to stop doing science, will allow him to be involved in the evaluations.
Soon after He revealed his experiment, it became clear that he did not act alone or in secrecy. The responsibility of other researchers who were in the know became hotly debated. The senior researcher with the most intimate knowledge of the work seems to be Michael Deem, a biophysicist at Rice University in Houston, Texas. What role he had is not clear. But they insist that Deem does not do human research, and did not do so for this project.
They say that he did not attend recruitment or informed-consent meetings, did not authorize the use of his name as an author on any human-gene-editing paper and was not a senior author on the paper.
Other scientists have been chastised for doing nothing to raise alarms about the work. He Jiankui told many US-based academics about what he was doing, including three at Stanford University in California, and Craig Mello, a Nobel-prizewinning molecular biologist at the University of Massachusetts Medical School in Worcester, who was an adviser for a company founded by He.
Most of them say that they advised He against proceeding. Mello says He ambushed him during a break at an advisory board meeting to tell him of his plans and then notified him of the pregnancies by e-mail. But Natalie Kofler, a molecular biologist at Yale University in New Haven, Connecticut, argues that researchers who knew about this should have done more. The whole episode, she says, is evidence of a growing divide between the values scientists proclaim, and those they actually uphold.
Others cite similar reasons. Alta Charo, who specializes in law and bioethics at the University of Wisconsin—Madison, agrees that it was unclear how any of these individuals could have effectively blown the whistle. But China has different values and opaque regulations. She says this could change if the scientific community follows through on plans mapped out at a gene-editing summit held in Hong Kong in November — the only scientific forum at which He has presented his work.
The plans propose some kind of transnational advisory body and registry to identify common norms and differences of opinions between countries. Other organizations are also considering measures. Earlier this month, for example, the World Health Organization announced the establishment of an international committee to devise guidelines for human gene editing.
June He Jiankui launches a project to edit genes in human embryos, with the goal of a live birth. March He starts recruiting couples each with an HIV-positive father for the experiments. Early November Gene-edited twin girls are reportedly born, and a second pregnancy with a third gene-edited embryo is established.
January He is censured by the Guangdong health ministry and fired from his university. Four years ago, a team of scientists from Guangzhou published a paper 1 describing the use of gene-editing techniques in a human embryo. The researchers used embryos with a mutation that would prevent them from growing into fetuses. It was, nevertheless, an earthshaking study, and it triggered immediate questions about germline editing. Over the next two years, several groups — from China, the United States and the United Kingdom — published results 2 — 4 of similar experiments.
The studies went from using non-viable embryos to using ones that could conceivably be implanted. Some tested new gene-editing techniques or combined gene editing with cloning. The experiments triggered warnings.
Although the scientists involved touted their work as careful basic research, many ethicists saw only one possible outcome: a clinical application not unlike what He has claimed to have done.
Following the fiasco with He, will those who are conducting embryo experiments face a backlash? The distinction between the two is based on purpose.
Gene therapy seeks to alter genes to correct genetic defects and thus prevent or cure genetic diseases. 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.
0コメント