AP Biology class blog for discussing current research in Biology

Tag: #GMO

How Gene-edited Strawberries are Safe and Beneficial to the Consumer

Over one-third of purchased strawberries end up getting thrown in the trash due to bruising, mold, or mushy texture. However, The J.R. Simplot Company and Plant Sciences Inc. hope to change this outcome. The pair of companies plan to modify the DNA of strawberries with the help of CRISPR-Cas9 and sell them on a commercial scale— and don’t worry! Recently published research suggests that it is safer than other alternatives.

These gene modifications aim to extend strawberry shelf life, prolong its growing season, and reduce consumer waste. This essentially means that farmers can efficiently grow more quality fruit for longer portions of the year.

CRISPR-Cas9 is a tool derived from the immune defense system in Streptococcus Pyogenes bacteria and is currently repurposed to edit sections of DNA sequences. CRISPR-Cas9 or the CRISPR/Cas9 system is primarily made up of the Cas9 protein, crRNA, and tracrRNA (or, more simply, guide RNA). 

As we have learned in AP Biology, RNA is a single-stranded molecule crucial to the processes of coding, decoding, regulation, and expression of genes. Our initial understanding of RNA holds to be true as the human-engineered guide RNA from the CRISPR/Cas9 system dictates exactly where the protein to cuts in the sequence. After the targeted section is cut, the Cas9 protein removes the particular section of DNA. Then, Host DNA can be placed in the removed portion of the DNA sequence and elicit a desired trait in the gene. For a deeper explanation of how CRISPR-Cas9 functions, I recommend watching Paul Andersen’s YouTube video on the subject.

This is exactly how The J.R. Simplot Company and Plant Sciences Inc. plan to genetically modify the genes within the strawberry.

This technology is far more efficient than the cumbersome process of selective crop breeding. To boot, Plants modified by the CRISPR/Cas9 system were found to be nearly identical to plants bred using traditional methods. The CRISPR/Cas9 system has also been found to have been thousands of times less likely to target the wrong stretch of DNA, making it potentially much safer than alternative methods of gene editing.

In the near future, The Simplot and Plant Sciences Inc. team plan to sell the strawberries after they identify the key genomes that determine shelf life and edit the plants for ideal crops. 

Strawberries picked

Do you think this is exciting news? Would you try a gene-edited strawberry? Why or why not?

Click Here to Learn About the Tomato’s Fancy New Makeover

The sun rose on a dimly light Monday morning when Adriano Nunes-Nesi, Lázaro E.P. Peres, Agustin Zsögön, Lucas de Ávila Silva, Ronan Sulpice, and Emmanuel Rezende Naves published their groundbreaking discovery that could revolutionize the cultivation of chili’s forever.   These insanely talented and well established scientists figured out how to use the CRISPR-Cas9 editing tool to turn a tomato into    a chili.

Capsaicinoids are what give peppers their heat and when these scholars of science mapped the tomato’s and chili’s genomes, they saw that the tomato has genes that, when transcribed, produce these spicy and hot capsaicinoids.

The reason why this is important is because the chili’s cultivation process is extremely tedious and requires many specific conditions, not to mention it having a small yield.  Since the yield of tomatoes is 30x that of the chili, using the CRISPR-Cas9 tool, they could change the shape and taste of the tomato to that of a chili. The price of a chili peppers, per kg, compared to tomatoes is roughly 60 cents higher. It may not seem a ton, but in bulk orders, it quickly adds up.

Lázaro E.P. Peres, who is aProfessor of Plant Physiology at the University of São Paulo and one of the scientists on the team, says, “The proof of concept here is that we can transfer the unique thing endemic to a less-produced plant into another plant that is more widely produced”.  The paper states the tomato “is highly amenable to biotechnological manipulation”. This would drive the price of the chili down which would help markets, restaurants, and Gardners worldwide.

The only issue to this is the publics opinion. For years, the already established “organic” companies having been labelling genetically modified food as unhealthy compared to non-GMO foods.  This claim is simply outright false.  “Any plant or animal product is full of DNA that our body readily digests, messing with one or two genes isn’t going to impact human health. The only way GM food could affect human health is if the modification somehow produce a protein product that was actively toxic to humans.”  This quote is from an article by the Genetic Literacy Project, which could be seen as having bias towards GMO foods, however their mission says,”is to aid the public, media and policymakers in understanding the science and societal implications of human and agricultural genetic and biotechnology research and to promote science literacy.”  All they are interested in doing is educating the public because so many people have been lied to by big organic corporations and the media to prevent customers from eating GMO products.  What would they have to gain by saying they are safe when they are not?    If the public can get passed the idea of genetically modifying foods, I believe turning a tomato into a chili pepper would save much money from hundreds of thousands of businesses– big or small.

What do you guys and gals think of GMO products?

For more information, please go check out the primary source of this article and the researchers report



A Much-So-Symmetrical Embryo

Developmental biology has taken a step further in understanding the connection made between the placenta and fetus by testing a hypothesis that involved slowing down the growth of one limb on an animal. Scientist Alberto Roselló-Díez used laboratory raised mice to test out his hypothesis by genetically manipulating the cells of a fetus in a petri dish. He then inserted the genetically modified cells into the mouse’s back left leg. A deeper look at Díez’s work explains that he uses a “p21” suppressor which is also known as an “antiproliferative”. In doing so, Roselló-Díez is suppressing chondrocyte cells (found in cartilage) from forming, thus preventing the mouses bones from lengthening.

In response to the cellular suppression, the nature of the fetus’s growth as a whole slows down to the growth rate of the left hind leg;  putting me in the mind of the phrase- “no man left behind”. This is described to be a “compensatory mechanism”, in which the entire fetus makes up for the compromised development of the mouse to keep it’s symmetry.

You might be wondering- “how does the placenta play into this?” Apparently, the cells of the placenta systemically communicate to the tissues of the other limbs, and warn them to “SLOW DOWN!” Therefore the fetus of the mouse relies on biological signals from the mother’s placenta.

Picture by Maneesha S. Inamdar

All in all, minimizing the growth rate of limbs is intriguing because it leaves me wondering the extent of the experimental purpose. Will it be that in the future we will use the p21 suppressor on human fetuses? Will this study lead to a breakthrough for unanswered cosmetic and orthopedic phonomena? These questions are yet to be undertaken by developmental biologists and maybe even doctors.

What came first, the chicken, the egg, or the allergic reaction?

A new study showed the beneficial effects CRISPR/Cas9 can have on those with allergies… in this case, to chickens! For those who don’t know, CRISPR/Cas9 is a gene-editing tool that is used to target certain parts of DNA and modify, disable or enable them. The tool haScreen Shot 2016-04-11 at 12.45.11 AMs been used all across science to inhibit diseases, fix problems with fetuses, change traits, and now to help genetically modify food. Using CRISPR/Cas9 is different than the current definition of genetically modified, which includes injecting chemicals into the food to maximize the amount or change some part of it. This means we humans are ingesting the chemicals; this has led to many concerns. However, CRISPR/Cas9 uses a different approach.

In this specific example, CRISPR/Cas9 creates knockout chickens, or chickens that have had their genes “knocked out”, turned off. Specifically, the ovalbumin (OVA) and the ovomucoid (OVM) genes.  These genes code for proteins that are found in egg whites. It has been discovered that many people are allergic to the proteins produced, so CRISPR/Cas9 targets the genes and turns them off and no proteins are produced. These “genetically modified” eggs are the same as regular eggs just hypoallergenic. In addition, some vaccines are made with egg whites, CRISPR/Cas9 will make it possible for the people who usually have an immune response to the egg whites in those vaccines, to safely receive them. One of the most notable vaccines that uses egg whites is influenza, a very popular vaccine that most of the population receives, and those who couldn’t were at a disadvantage before CRISPR/Cas9. The scientists have said they will continue to cross the modified chickens to see if they are able to knockout more common allergens. So no matter if the chicken or the egg came first, they are now both safe to consume by humans.


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