Debunking 11 popular GMO Myths: Part I: Frankenfoods and Franken-corporations || Part II: Do GMOs pose health and ecological dangers? by Michael Hess & Peter Hess
Happy Friday (or should we say, Fri-YAY) from CauseScience!
psgurel– Today I am miniprepping! If you remember last week, I was doing PCR to get a specific DNA construct. After doing PCR, there are several steps before you have nice clean DNA. For the DNA I’m using (plasmid DNA) the final step is to extract your DNA from bacteria. Lucky for us, several companies make “miniprep” kits that make this process super quick and easy. It takes about 30min, and then you have (hopefully) nice, clean DNA!
crestwind24– This is crazy! I am also doing mini preps of DNA this morning!! SAMESIES!! Preparing DNA is a major part of most labs, as made obvious by todays post. I am making DNA that will label synapses in neurons in C. elegans. Once I have the DNA that I want, we will inject it into developing embryos, and then I will have transgenic worms!! Hopefully with glowing synapses!! This will allow me to visualize connections between different neurons.
CauseScience Friday… more like mini prep Friday!!!
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In case you didn’t see the media coverage of an abstract from the recent meeting of the American Society of Human Genetics in Baltimore, Maryland (see Nature News stories here), an abstract presented preliminary data in the search for the genetic roots of homosexuality in human twins. Obviously this scientific presentation, and the press release about it from the conference, generated excitement, skepticism, and now controversy. Nature has a terrific editorial this week examining how this was a failure in science communication. Scientific conferences and meetings are meant to be a place to present preliminary, controversial, and incomplete studies to scientific peers to get feedback, ideas, and promote the work being done. Criticism of the work and experiments are always a part of this process, but where do we draw the line?
A few critics went so far as to argue that the authors should not have presented such preliminary work at the meeting. And at least one suggested that the authors could have provided preprints of their study when presenting it. These arguments seem to misunderstand the traditional, and still useful and relevant, role of such gatherings. Studies with small sample sizes and controversial methods are presented at conferences all the time, and many scientists already fear being scooped when they present even a bit of their data.
One might wonder how so much media coverage was generated from a scientific conference abstract, and the answer is that the conference used the abstract in a press release, unfortunately titled, ‘Epigenetic Algorithm Accurately Predicts Male Sexual Orientation.’ While this may represent the science, it opens the door for misinterpretation by non-scientists that never saw the data presented. This failure in science communication has a remedy, and it involves being careful with press releases of unpublished, non-peer-reviewed science, especially on topics that could be ‘misused’ or misinterpreted by the press.
The genetics of homosexuality is a subject that will always find media coverage, partly because of the societal interest in the topic. Neither the scientists nor the conference organizers can be held responsible for how some in the media chose to write about the study. But both could have done more to get the right message across.
Check out this podcast episode from Radiolab focusing on CRISPR and its potential applications.[tweet https://twitter.com/CauseScience1/status/611576799013769217]
Out drinking with a few biologists, Jad finds out about something called CRISPR. No, it’s not a robot or the latest dating app, it’s a method for genetic manipulation that is rewriting the way we change DNA. Scientists say they’ll someday be able to use CRISPR to fight cancer and maybe even bring animals back from the dead. Or, pretty much do whatever you want. Jad and Robert delve into how CRISPR does what it does, and consider whether we should be worried about a future full of flying pigs, or the simple fact that scientists have now used CRISPR to tweak the genes of human embryos.
As mentioned previously, a moratorium has been called on the new gene editing technique using the CRISPR/Cas9 system due to ethical concerns over altering genes. Essentially, biologists fear that this technique will be used in cilinical applications before the safety can be determined and ALSO are worried about ethical issues surrounding the technique of editing genes.
In light of all this, a new controversy has surfaced following the publication in Protein & Cell of work from Chinese scientists who essentially tried to delete a gene from human embryos that causes a fatal blood disorder. While the CRISPR/Cas9 system definitely has potential, the work from this group clearly shows that their current method of gene editing has several off target effects and is absolutely not ready for any sort of clinical trial.
NPR summarizes the whole ordeal:
For the first time, scientists have edited DNA in human embryos, a highly controversial step long considered off limits.
Junjiu Huang and his colleagues at the Sun Yat-sen University in Guangzhou, China, performed a series of experiments involving 86 human embryos to see if they could make changes in a gene known as HBB, which causes the sometimes fatal blood disorder beta-thalassemia.
The report, in the journal Protein & Cell, was immediately condemned by other scientists and watchdog groups, who argue the research is unsafe, premature and raises disturbing ethical concerns.
“No researcher should have the moral warrant to flout the globally widespread policy agreement against modifying the human germline,” Marcy Darnovsky of the Center for Genetics and Society, a watchdog group, wrote in an email to Shots. “This paper demonstrates the enormous safety risks that any such attempt would entail, and underlines the urgency of working to forestall other such efforts. The social dangers of creating genetically modified human beings cannot be overstated.”
George Daley, a stem cell researcher at Harvard, agreed.
“Their data reinforces the wisdom of the calls for a moratorium on any clinical practice of embryo gene editing, because current methods are too inefficient and unsafe,” he wrote in an email. “Further, there needs to be careful consideration not only of the safety but also of the social and ethical implications of applying this technology to alter our germ lines.”
Scientists have been able to manipulate DNA for years. But it’s long been considered taboo to make changes in the DNA in a human egg, sperm or embryo because those changes could become a permanent part of the human genetic blueprint. One concern is that it would be unsafe: Scientists could make a mistake, which could introduce a new disease that would be passed down for generations. And there’s also fears it this could lead to socially troubling developments, such as “designer babies,” in which parents can pick and choose the traits of their children.
The Chinese researchers say they tried this to try to refine a new technique called CRISPR/Cas9, which many scientists are excited about it because it makes it much easier to edit DNA. The procedure could enable scientists to do all sorts of things, including possibly preventing and curing diseases. So the Chinese scientists tried using CRISPR/Cas9 to fix a gene known as the HBB gene, which causes beta thallasemia.
The work was done on 86 very early embryos that weren’t viable, in order to minimize some of the ethical concerns. Only 71 of the embryos survived, and just 28 were successfully edited. But the process also frequently created unintended mutations in the embryos’ DNA.
“Taken together, our data underscore the need to more comprehensively understand the mechanisms of CRISPR/Cas9-mediated genome editing in human cells, and support the notion that clinical applications of the CRISPR system may be premature at this stage,” the Chinese scientists wrote.
Rumors about this research have been circulating for weeks, prompting several prominent groups of scientists to publish appeals for a moratorium on doing this sort of thing.
In the wake of the report from the Chinese scientists, several of these researchers reiterated their call for a moratorium. Some said they hoped the difficulties that Huang and his colleagues encountered might discourage other scientists from attempting anything similar.
“The study simply underscores the point that the technology is not ready for clinical application in the human germline,” Jennifer Doudna, the University of California, Berkeley, scientist who developed CRISPR, wrote in an email. “And that application of the technology needs to be on hold pending a broader societal discussion of the scientific and ethical issues surrounding such use.”
But there are already reports that Huang’s group and possibly others in China continue to try editing the genes in human embryos.
“We should brace for a wave of these papers, and I worry that if one is published with a more positive spin, it might prompt some IVF clinics to start practicing it, which in my opinion would be grossly premature and dangerous,” Daley says.
What do YOU think about the CRISPR/Cas9 technology? Should a moratorium be placed? Does the technology show promise for curing disease in the future? Or is this whole thing unethical? Share your opinions in the comments or tweet at us @CauseScience1.
Not all GMO plants are created equally: it’s the trait, not the method, that’s important
Many people have strong opinions about genetically modified plants, also known as genetically modified organisms or GMOs. But sometimes there’s confusion around what it means to be a GMO. It also may be much more sensible to judge a plant by its specific traits rather than the way it was produced – GMO or not.
This article is not about judging whether GMOs are good or bad, but rather an explanation of how plants with modified genomes are made. (There are non-plant GMOs, but in this article we will only refer to plant GMOs.) First of all, it’s necessary to define what we mean by a GMO. For the purposes of this discussion, I’m defining GMOs as plants whose genetic information (found in their genomes) has been modified by human activity.
Humans have changed the genomes of virtually all the plants in the grocery store
If we think of GMOs as plants that have genomes modified by humans, then quite a lot of the plants sold in any grocery store fit that description. But many of these modifications didn’t occur in the lab. Farmers select plants with superior, desirable traits to cultivate in a process known as agricultural evolution. Thousands of years of traditional agricultural breeding has changed plant genomes from those of their original wild ancestors.
Broccoli, for example, is not a naturally occurring plant. It’s been bred from undomesticated Brassica oleracea or ‘wild cabbage’; domesticated varieties of B. oleracea include both broccoli and cauliflower. Broccoli, along with any seedless variety of fruit (including what you think of as bananas), and most of the crops grown on farms today would not exist without human intervention.
However, these aren’t the plants that people typically think of when they think of GMOs. It’s easy to understand how farmers can breed better plants on farms (by choosing to plant seeds from the biggest or best-yielding plants, for example, imposing artificial selection on the crop species) so even though this activity changes plant genomes in ways nature wouldn’t have, most people don’t consider these plants GMOs.
Creating “lab” GMOs
Once plant genes had been studied enough, researchers could turn to backcrossing. This technique involves breeding the offspring back with the parents to try to get a desired, stable combination of parental traits. Genes previously linked to desirable plant traits, such as higher yield or pest-resistance, could be identified and screened for using molecular biology techniques and linkage maps. These maps lay out the relative position of genes along a chromosome, based on how often they are passed along together to offspring. Closer genes tend to travel together.
Researchers used molecular markers – specific, known gene sequences, present in the linkage maps – to select individual plants that contained both the new marker gene and the greatest proportion of other favorable genes from the parents. The combinations of genes passed to offspring are always due to random recombination of the parents’ genes. Researchers weren’t able to drive particular combinations themselves, they had to work with what arose naturally; so in this marker-assisted selection approach, there’s a lot of effort and time spent trying to find plants with the best combinations of genes.
In this system, a laboratory needs to screen the genomes, using molecular biology methods to look for particular gene sequences for desirable traits in the bred offspring. Sometimes a lab even breeds the plants in cases using tissue culture – a way to propagate many plants simultaneously while minimizing the resources needed to grow them.
Inserting non-plant genes into GMOs
In the early 1980s, the plant biotechnology era began with Agrobacterium tumifaciens. This bacterium naturally infects plants and, in the wild, creates tumors by transferring DNA between itself and the plant it has infected. Scientists use this natural property to transfer genes to plant cells from an A. tumifaciens bacterium modified to contain a gene of interest.
For the first time, it was possible to insert specific genes into a plant genome, even genes that do not come from that species – or even from a plant. A. tumifaciens does not affect all plants, however, so researchers went on to develop DNA-transferring methods inspired by this system which would work without it. They include microinjection and “gene guns,” where the desired DNA was physically injected into the plant, or covered tiny particles that were literally shot into the nuclei of plant cells.
A recent review summarizes eight new methods for altering genes in plants. These are molecular biology techniques that use different enzymes or nucleic acid molecules (DNA and RNA) to make changes to a plant’s genes. One route is to alter the sequence of a plant’s DNA. Another is to leave the sequence alone but make other epigenetic modifications to the structure of a plant’s DNA. For instance, scientists could add arrangements of atoms called methyl groups to some of the nucleotide building blocks of DNA. These epigenetic modifications, while not altering the order of the DNA or of genes, change how genes can be expressed and thus the observable traits a plant has.
GMO doesn’t mean glyphosate-resistant
Calling a plant a genetically modified organism means only that – its genome has been modified by the activity of humans. But lots of people conflate the idea of a GMO plant with one that’s been created to be resistant to the herbicide glyphosate, also known by the brand name Roundup. It’s true that the most well-known GMO crops currently grown contain a gene that makes them resistant to glyphosate, which allows farmers to spray the chemical to kill weeds while allowing their crop to grow. But that’s just one example of a gene inserted into a plant.
It’s sensible to evaluate GMOs not on how they are made, but rather on what new traits the modified plants have. For instance, while it can be argued that glyphosate resistance in plants is not good for the environment because of increased use of the pesticide, other GMOs are unlikely to cause this problem.
For example, it’s difficult see how the controversial golden rice, which has been engineered to produce vitamin A in the rice grains to be more nutritious, is worse for the environment than ordinary rice. GMOs have been developed to express a pesticide permitted in organic farming: Bt toxin, an insecticide naturally produced by the bacterium Bacillus thuringiensis. While this may reduce pesticide use, it may also lead to the evolution of Bt-resistant insects. And there are GMOs which have improved storage characteristics or nutritional content, like “Flavr Savr” tomatoes, or pineapples that contain lycopene, and tomatoes that contain anthocyanins. These compounds are ordinarily found in other fruits and are thought to have health benefits.
The so-called “fish tomato” contains an antifreeze protein (gene name afa3), found naturally in winter flounder, that increases frost tolerance in the tomato plant. The tomato doesn’t actually contain fish tissue, or even necessarily DNA taken from fish tissue – just DNA of the same sequence present in the fish genome. The Afa3 protein is produced from the afa3 gene in the tomato cells using the same machinery as other tomato proteins.
Is there any fish in the tomato plant? Whether DNA taken from one organism and put into another can change the species of the recipient organism is an interesting philosophical debate. If a single gene from a fish can make a “fish tomato” a non-plant, are we human beings, who naturally contain over a hundred non-human genes, truly human?