The potential impact of CRISPR on the biosphere is equally profound. Last year, by deleting all three copies of a single wheat gene, a team led by the Chinese geneticist Gao Caixia created a strain that is fully resistant to powdery mildew, one of the world¡¯s most pervasive blights. In September, Japanese scientists used the technique to prolong the life of tomatoes by turning off genes that control how quickly they ripen. Agricultural researchers hope that such an approach to enhancing crops will prove far less controversial than using genetically modified organisms, a process that requires technicians to introduce foreign DNA into the genes of many of the foods we eat...also btw...
Inevitably, the technology will also permit scientists to correct genetic flaws in human embryos. Any such change, though, would infiltrate the entire genome and eventually be passed down to children, grandchildren, great-grandchildren, and every subsequent generation. That raises the possibility, more realistically than ever before, that scientists will be able to rewrite the fundamental code of life, with consequences for future generations that we may never be able to anticipate. Vague fears of a dystopian world, full of manufactured humans, long ago became a standard part of any debate about scientific progress. Yet not since J. Robert Oppenheimer realized that the atomic bomb he built to protect the world might actually destroy it have the scientists responsible for a discovery been so leery of using it.
Editas is one of several startups, including Intellia Therapeutics and CRISPR Therapeutics, that have plans to use the technique to correct DNA disorders that affect children and adults. Bosley said that because CRISPR can ¡°repair broken genes¡± it holds promise for treating several thousand inherited disorders caused by gene mistakes, most of which, like Huntington¡¯s disease and cystic fibrosis, have no cure.posted by a lungful of dragon at 1:12 AM on November 16, 2015
Editas, which had not previously given a timeline for an initial human test of CRISPR, will try to treat one form of a rare eye disease called Leber congenital amaurosis, which affects the light-receiving cells of the retina.
The condition Editas is targeting affects only about 600 people in the U.S., says Jean Bennet, director of advanced retinal and ocular therapeutics at the University of Pennsylvania¡¯s medical school. ¡°The target that they have selected is fantastic; it has all the right characteristics in terms of making a correction easily,¡± says Bennett, who isn¡¯t involved in the Editas study.
Two new studies from the University of California, Berkeley, should give scientists who use CRISPR-Cas9 for genome engineering greater confidence that they won't inadvertently edit the wrong DNA.posted by a lungful of dragon at 1:21 AM on November 16, 2015
The gene editing technique, created by UC Berkeley biochemist Jennifer Doudna and her European colleague Emmanuelle Charpentier, has taken the research and clinical communities by storm as an easy and cheap way to make precise changes in DNA in order to disable genes, correct genetic disorders or insert mutated genes into animals to create models of human disease.
The two new reports from Doudna's lab and that of UC Berkeley colleague Robert Tjian show in much greater detail how the Cas9 protein searches through billions of base pairs in a cell to find the right DNA sequence, and how Cas9 determines whether to bind, or bind and cut, thereby initiating gene editing. Based on these experiments, Cas9 appears to have at least three ways of checking to make sure it finds the right target DNA before it takes the irrevocable step of making a cut.
"This is definitely a thread about human engineering, but I should clarify my comment was about, for lack of a better term, gene deleted food. Hence the comment about toxicity. Presumably you don't care too much about family trees when you're buying GMO seeds with terminator genes."There is a reason why there haven't really been voices talking about "toxicity" related to GMOs that don't also betray fundamental misunderstandings of the molecular genetics underlying genetic engineering since the 90s. The genetic information of the things we eat is constantly mutating with far more dramatic deletions, insertions, and substitutions than anything we do intentionally without anyone being any the wiser, much less batting an eyelid. Besides, Genetic Use Restriction Technology (GURT), colloquially known as terminator seeds, were developed by the Agricultural Research Service of the USDA and the Delta and Pine Land company in the 1990s, but were never used and likely never will be used. The people who succeeded at selling you a fear of them either didn't know they were never actually a thing, or just as likely didn't care to know.
"I will say that removing genes from humans has a whole host of ethical issues beyond 'is it toxic.'"What this article is talking about is making somatic mutations, editing cells involved in making the body operate, not making germline mutations that would edit cells involved in heredity. This is honestly no ethically different than administering any other therapeutic. Germline engineering though, is going to be a thing that we are going to need to talk about, this is where the global conversation has started with a lot of the people who were at Asilomar back in the day and new PIs at the forefront of things:
"We need to eliminate patents on genetic changes asap."For better or worse, the Supreme Court is way ahead of you and did this once and for all two years ago: Association for Molecular Pathology v. Myriad Genetics.
The New Yorker article is not correct on this point. I am aware of multiple gene-edited embryos that have been carried to term and that are one the ground right now. They're not humans, but they're mammals.The New Yorker article is quite clear this is several generations away from success in embryos. But I expect there are PGD/IVF labs that would be more than willing to work with an appropriately funded, interested couple to move this along rapidly. Too bad the ethics and legal sides won't move equally rapidly.
"How could you possibly know that?"I don't work with Eukaryotes, but this should be super trivial. Just looking at whether whatever you're repressing has DNA or RNA binding domains in hmmer, and double checking that the transcripts produced aren't antisense for other transcripts by BLASTing the complimentary sequence, would do it. That's five minutes of effort. Even then, if you are the type of paranoid that leads people to protest the LHC as something that could END THE WORLD, RNA-Seq or microarrays with a few grand and a few months of a graduate student's time would firmly establish nothing was being differentially expressed but the target.
"Well, sure. There's a specific definition of gene repression geneticists use that I forgot about, and thus regret the precise framing of that question. I was primarily thinking of the problem in terms of the interactome, which is quite large and undocumented, so not yet amenable to search queries like BLAST and hmmer. It may take another generation before that process is mapped, or understand how much larger a problem domain than a genome it is."This is the level of concern for esoteric outcomes that makes sense for efforts edit patient somatic cells like in the FPP, much less germline cells, but I'm not at all convinced that the interactomics of recombinant mutants would even be meaningfully interesting to look at with yeast two hybrid screens in the kinds of crop species benzene dream was talking about. So long as any hypothetical interaction doesn't impact the viability of the critter, which would be immediately apparent by growing it, why should any hypothetical interaction even matter? We could certainly pull up an armchair and imagine scenarios where perturbations to the interactome could cause some hypothetical harm that would be too subtle to notice, but can we come up with any that wouldn't also be caused much more often by any other method of crop breeding? Just think about it, if anything the more distant the foreign genetic material being used is, the less likely it would be to affect the interactome at all - when we currently cross breed related plants with all sorts of kinky mechanisms for chromosomal recombination and apply gamma radiation to select for whatever within the wildly affected mutants without giving it a second thought.
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That's an interesting point, though I doubt it will work regularly. If the concern is rogue proteins with unknown toxicity or catalytic behaviors, removing coding DNA shouldn't contribute to concerns of food contamination. Unless their catatylic behavior turns a toxin into a nutrient...
Problem is that most every gene is subject to selection, and if natural selection favored keeping something, there might be some parasite or predator we don't know about applying that pressure.
posted by pwnguin at 12:31 AM on November 16, 2015 [3 favorites]