Thursday, April 23, 2015

Gene editing

"Making repairs using CRISPR harnesses a cell’s own DNA repair machinery to correct genes. The technology guides a cutting protein to a particular site on the DNA molecule, chopping it open. If a DNA 'repair template' is provided—in this case a correct version of the beta-globin gene—the DNA will mend itself using the healthy sequence.
The Chinese group says that among the problems they encountered, the embryo sometimes ignored the template, and instead repaired itself using similar genes from its own genome, 'leading to untoward mutations.' 
Huang said he stopped the research after the poor results. 'If you want to do it in normal embryos, you need to be close to 100 percent,' Huang told Nature News. 'That’s why we stopped. We still think it’s too immature.'"


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  1. As for society deciding if the technique is ethical, what method do the scientists calling for a halt have in mind? A national referendum? A determination by elected representatives in Congress, some of whom have shown themselves to be either scientifically ignorant or patently anti-science?

    One has only to look at the abysmal failure of "society" to agree on the ethics of abortion, contraception, the importance of vaccinating children, and a host of nonmedical issues to conclude that seeking to obtain society's agreement on what is ethical is an exercise in futility.

    This is one of those rare instances in which I maintain that a line must not be crossed. Editing the genes of human embryos -- or fertilized eggs -- to eradicate a heritable disease should not be attempted.'sTablet/51460?xid=nl_mpt_DHE_2015-05-12&eun=g906366d0r&userid=906366&mu_id=5793688

  2. Recently, Chinese scientists published a paper in a fairly obscure journal, announcing a remarkable experiment that I think was unethical. The experiment involved using CRISPR/Cas9, a new genome-editing technique that allows scientists to snip genes and insert new genetic information.

    Many American and European scientists also have been working on this technique, but the Chinese scientists took it a step further by altering human embryos and trying to insert messages into them.

    These embryos never came out of their dishes, but the experiment is still deeply troubling. These scientists crossed the line from somatic to germline engineering.

    Prior to this point, almost all genetic engineering has involved changes to the body's cells. If you are trying to treat blindness or cystic fibrosis, for example, you make changes in the cells, but the changes are not passed along to future generations.

    Obviously, altering cells in an embryo is different. Doing so passes these modifications on to descendants who never had the opportunity to consent and will have to deal with the unanticipated consequences of gene modification.

    The Chinese researchers have set the precedent that it is all right to change our genes, knowing that these changes will reach our descendants.

    I am not sure whether this practice is wrong, per se, but if you are going to do this kind of experiment, you need a lot more approval, international discussion, and supervision than seems to have been the case here.

    The authors did not reveal much about where the embryos came from or whether people gave consent for their use. They do not discuss what the limits might be—if there are any—on trying to change genes in our descendants. Is it just to repair hereditary diseases? Will we try to enhance or improve our traits by selecting features for our children that we think are appealing? How should we use this technology? When should we not?

    We need to have some serious and transparent public discussion. The Chinese investigators did this experiment, published it, and there it was. That fact may frighten the public because of the perception that there are renegades out there who are going to do whatever they want and there is no way to control them. This perception may ultimately lead to taking away a tool that could be useful in the battle against disease

    What might be some ways to rein in these types of researchers? There could be criminal penalties, like jail, if scientists perform these kinds of experiments without approval. Or journal editors could refuse to publish these studies unless they have undergone a long approval process. The media could even say, "We are not going to announce certain studies without mentioning the fact that investigators failed to get proper ethical approval first."

    We are not powerless, but we have to put our foot down and say that if you are going to make a leap into an area like germline engineering, there should be more than one team conducting the studies.

    The results of this experiment were useless. That is why the study did not appear in a major journal. The researchers tried to insert genetic information, but they did not do it well and they did not learn anything worth reporting. The paper concludes by saying, "We need more work on this."

    The study should not have been published at all. Bad science combined with bad ethics is just bad.