BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: Embryo

Embryo Gene Editing can Ensure Offspring Do Not Inherit a Deafness Gene!

Denis Rebrikov, A scientist in Russia has done research regarding ways in which he can edit the genome sequence of an embryo in order to prevent the fetus from developing certain gene mutations, specifically in this case a hearing problem or possible complete deafness. His plans are very controversial to some, who believe the possible risks of very harmful mutations to DNA that would be passed onto direct and future offspring, outweigh the possible benefits. However, some people find this scientific possibility to be worth the risk, if it means not passing a potentially very harmful gene down to offspring. If these methods are done correctly, it should alter the genome sequence in the embryo so that future offspring off that embryo will not inherit the negative mutation.

One couple shared their story in detail, in which both parties have a hearing deficiency, the man with partial deafness, and the woman completely deaf. Their biggest hope is to have children who will not inherit hearing issues, because of the apparent challenges they have had to face themselves because of them. They would be the first couple to perform this gene editing on an IVF embryo, so they obviously have some reservations. One of those being publicity, but more importantly the potential risks of using the CRISPR genome editor. They already have a daughter with hearing loss, but they never chose to test her genes for mutations, nor did they get her a cochlear implant to aid her hearing, because of the potential risks of that. When they finally tested her genes, they learned that she had the same common hearing loss mutation called 35delG in both her copies of a gene called GJB2. The parents then tested themselves, realizing they were both 35delG homozygous, meaning their daughter’s mutations were not unique to her, they had been inherited.

If either the mother or father had a normal copy of the GJB2 gene, a fertility clinic could have more easily created embryos by IVF and tested a few cells in each one to select a heterozygote–with normal hearing–to implant. At this stage, Denis Rebrikov informed them that CRISPR genome editing would be their only option. However, the process presents possibly deal breaking risks, such as mosaicism, in which a gene edit might fail to fix the deafness mutation, which could create other possible dangerous mutations like genetic disorders or cancer. The couple has not decided to go through with the editing just yet, but it is something they are open to in the future as more possible new research or test subjects become available.

Explaining the CRISPR Method: “The CRISPR-Cas9 system works similarly in the lab. Researchers create a small piece of RNA with a short “guide” sequence that attaches (binds) to a specific target sequence of DNA in a genome. The RNA also binds to the Cas9 enzyme. The modified RNA is used to recognize the DNA sequence, and the Cas9 enzyme cuts the DNA at the targeted location… Once the DNA is cut, researchers use the cell’s own DNA repair machinery to add or delete pieces of genetic material, or to make changes to the DNA by replacing an existing segment with a customized DNA sequence.” -US National Library of Medicine Genetics Home Reference

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Woman with a hearing aid 

If you had the opportunity to alter something in the gene’s of your baby’s embryo, would you? Under what circumstances would you consider this, and what risks might stop you from deciding to do it? Comment down below.

 

 

Forbidden Baby Editing

We all at this point in life have come to know what gene editing is. The technology for it is slowly and forever becoming more and more advanced. The scary thing about editing genes is the fact that we have to potentially affect a baby’s life their entire time alive. It has many different problems which is why its going to take a long time for it to fully get approved in the hospital.

Well unfortunately in an article found here there was a fright to figure out that someone had actually edited the genomes of some babies without people knowing. Many scientists condemned scientist He Jianku as it came to light that he had done something that the science was not ready for yet. He used CRISPR Cas9 tech in order to alter some genes of a few babies. The definition of CRISPR is here but basically it is a general tech to edit the genomes of babies that haven’t been born yet. People were up in arms about the process because he had bypassed the ethical laws and needed up editing the genes of a real live human. People in the science community go on to say that the CRISPR technology just isn’t ready to be executed on a human. There needs to be many more trials before it is used on a person for real. There is progress to make sure this doesn’t happen such as fines and bans from research however they are trying to make sure that it doesn’t happen at all. It gives scientists a bad name and he is trying his best to not let that happen. Technology will always advance and the hard part is trying to make sure that tech is ethical. Hopefully this gives insight to how we can prevent things like this happening in this day and age

Genetically Modified Babies?

A decade or two ago, the idea of being able to modify embryos was straight out of a science-fiction movie. However, last November, Chinese scientist He Jiankui genetically modified twin girls’ embryos to have resistance to the HIV virus using a process called CRISPR. His actions have sparked a global panic, as many people feel that current regulations are not enough to keep the scientific community’s actions ethical.

To understand this issue, it is important to understand its individual components. CRISPR is a gene-editing tool that was discovered in 2007 and became widely used in 2013. Essentially, a scientist decides what portion of DNA they would like to alter, and transcribes the sequence into RNA. This RNA finds the portion of DNA with the specific code and then the Cas9 enzyme “cuts” the DNA, allowing a new sequence of DNA to take its place.

The image depicts functions of CRISPR Cas9 technology.

Dr. He used CRISPR Cas9 technology to try to block the HIV pathways in twin girls while they were still embryos. As this experiment was recent, the long-term effects of it are unclear. In addition, as these girls were not developed at the time of their gene editing, they did not give consent to have a treatment that could be detrimental to their health. Furthermore, looking at the Centers for Disease Control website, HIV is primarily acquired by the use of unsafe needles to inject drugs and sexual contact. Using clean needles and condoms can greatly decrease one’s risk of getting HIV, and if a HIV-positive person takes suppression medicines, the viral content of HIV in their blood can become undetectable. Dr. He’s actions gave the twin girls undue risk, with little possible benefit.

In the future, this method of gene editing may be used to prevent or treat genetic diseases, but people have little knowledge of the long-term implications of using this technology on embryos. At the moment, the lack of global legislation regarding this gene-editing technology leaves a lot to be wondered about the future of this tool. According to Victor Dzau who works in the United States National Academy of Medicine, “The silver lining is that the world was awakened by the conduct of Dr. He, and we are all working very, very hard with all good intentions to make sure that this doesn’t happen again—not in the fashion that He did it. And that someday, if and when the technology is ready—and I think all of us are very bullish about this technology—that it will be helping humankind in the right way, knowing the risks and knowing the benefits.” After Dr. He’s experiment, many are in favor of halting the use of CRISPR on human embryos for at least five more years, so more research can be done on the subject. However, legislation, which the world has seen little of, holds a stronger weight than mere recommendations. In Russia, Denis Rebrikov is planning to create CRISPR babies, and regulations in the country regarding his specific goals remain unclear. How will CRISPR embryo editing evolve in the coming decades? Will CRISPR gene editing be as common someday as IVF is today?

 

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.

GATTACA is Here!

            In August of 2017 Scientists finally had figured out how to successfully edited genes in human embryos in order to treat serious disease-causing mutation using advanced CRISPER/Cas9. This is a  major milestone as it brings scientists closer to the reality of being able to genetically engineer babies in order to re

File:CRISPR-Cas9-biologist.jpg

Photo by J Levin W

pair faulty genes. This concept has always been feared due to the lack of success and safety of previous genetic tests, however, this study proves that scientists can now successfully edit genes.“We’ve always said in the past gene editing shouldn’t be done, mostly because it couldn’t be done safely,” said Richard Hynes, a cancer researcher at the MassachusettsInstitute of Technology who co-led the committee. “That’s still true, but now it looks like it’s going to be done safely soon,” he said, adding that the research is “a big breakthrough.” Genetic testing has also been regarded as unethical due to the possibility of eugenics, in which wealthy families would pay to have their embryos adjusted to get enhanced cosmetic traits such as height and muscle mass. “What our report said was, once the technical hurdles are cleared, then there will be societal issues that have to be considered and discussions that are going to have to happen. Now’s the time.” This successful study has come out only months after a national scientific committee recommended new guidelines for modifying embryos in which they strongly urge gene editing be used solely for severe hereditary medical conditions.

Stem Cells…Key to Youth and Controversy

Have you ever wondered what it would be like to be young forever? With the help of stem cells, this is possible. Stem cells can regenerate skin tissues and can also be used to treat diseases. However, something as enticing as living forever has its controversies. There are two types of stem cells: embryonic (ES) and adult (iPS); the embryonic stem cells are the controversial type.

Embryonic Stem Cell

Embryonic Stem Cell

The only way to effectively use the embryonic stem cell is to kill a four to six day old embryo. Some people view this act as killing a baby, which sparks ethical arguments about whether or not to utilize embryonic stem cells. To avoid this controversy, scientists have been trying to use stem cells from iPS cells instead of ES cells, but they questioned the power of iPS cells compared to the ES ones.

Because genes may differ in the iPS cells from the its source, the ES cells, there is a possibility that these two cells do not have the same capability. One scientist notes that the source of iPS and ES cells differ, which can lead to differences in gene activity. The ES cells are derived from embryos, which are not completely identical to iPS adult cells.  However, recent scientific research shows that these two types of stem cells have more equal capabilities than scientists’ initially thought.

Scientists conducted an experiment to compare the genetic makeup between the ES and iPS cell. They manipulated the male type of each cell, which eventually allowed the ES cell to transform into the iPS cell. They concluded that the iPS cells genetically matched the ES cells’ parents, and that the iPS cells had more similarities with the ES cells than iPS cells had to each other.

Even though these two experimental cells genetically matched, the two cells were not identical. The experiment showed 49 genes that differed between the two stem cells. Because of this difference, scientists needed to see if this affected the functional capability of the cells. The researchers conducted another experiment that analyzed 2 of the 49 genes. One helps take in glucose, while the other helps break it down. Even though these two genes were more active in the ES cell than the iPS cell, they were equally efficient at their respective jobs. The scientists concluded that these two specific cells were functionally equivalent.

The many experiments that have been conducted on the topic of stem cells contribute to the increase in research for more ways to utilize stem cells, without the ethical controversy. Scientists are starting to employ different technological devices, such as 3-D printers to help develop and build stem cells. This ability to fabricate cells using technology overcomes previous obstacles of limited stem cell resources.

– Source Article

– More fun facts about stem cells here

Monkey Be, Monkey Do

Are you one of those people who has always wondered about scientist’s progress in creating genetically amalgamated Monkeys? Well, if the answer is yes, then you need wonder no more, because Scientists have recently created their very own combinations of primate genes known as Chimeric Monkeys through the extensive study of stem cells and embryonic tissue.

The term Chimeric Monkey, stemming from the Greek Chimera, essentially describes the scientists efforts of combining various monkey genes in a prospective embryo, and empregnating a mother with said genes to direct what the eventual monkey child will develop into based on its new genes. It should be noted also that experiments with chimeric mice have also been a great asset in this venture, as they have provided certain genes which serve as “knock out” genes for  ones that the scientists wish to delete when creating the new monkey genome.

Shoukhrat Mitalipov of the Oregon National Primate Research Center at Oregon Health & Science University has been one of the primary figures in researching this new breakthrough chimeric studies saying that “The possibilities for science are enormous.” The basic procedure for creating the Chimeric monkeys entails the initial mixing of embryonic cells very early in their development that are classified as totipotent, or still having the capability of creating an entire animal with placenta, and other life sustaining tissues. Mitalipov has stated that “The cells never fuse, but they stay together and work together to form tissues and organs”.

So what do you all think? Is this all really a huge breakthrough in genetic science, or perhaps going a bit too far in what we were meant to manipulate?

Oh, and by the way, Mitalipov emphasized that there is no need or plans for chimeric humans,  just in case you were wondering

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