There are lots of methods that scientists use to alter an organism in order to study a particular topic or structure in that organism. Earlier in the spring semester of 2019, Heather Wheeler gave a talk at Loyola University Chicago about a gene-based association method called PrediXcan, which tests molecular mechanisms through which genetic variation affects different phenotypes. This triggered interest in other ways one can modify and alter gene expression in an organism in order to study interactions and defining roles of genes. There are multiple techniques in which one can do this, whether it be genome-wide association studies (GWAS) like in Wheeler’s talk, or other techniques such as a Cre-lox system or, what I’m interested in most, CRISPR.
Brad Plumer, Eliza Barclay, Julia Belluz, and Umair Irfan wrote an article in December of 2018 that talks about CRISPR very extensively. CRISPR stands for clustered regularly interspaced short palindromic repeats. What this essentially means is that it’s a method to edit genes/genomes. It is a system that is capable of adding, removing, or simply altering genetic material. This process has a similar mechanism to that of an adaptive immune response in that it must be exposed to a stimulus before being able to identify it in the future. This is all done in hopes of preventing and treating human diseases such as sickle cell, cystic fibrosis, and hemophilia.
How this system began was that it is a naturally occurring mechanism in bacteria and was slightly modified to be used on animals. CRISPR is a combination of a Cas9 enzyme that binds and cleaves the complimentary DNA, and a guide RNA that acts a GPS for the Cas9. A small piece of RNA with this “guide” sequence is created and is made to bind to a specific target sequence of DNA in a genome. The Cas9 enzyme, which is bound to the guide RNA then cleaves the DNA at that spot and this is where the magic happens. When it is cut, experimenters use the natural repair mechanism of the organ to their advantage, adding or removing genetic material that they wish to alter.
Why is any of this important? Plumer and his team continue to discuss some applications of CRISPR from very practical scenarios to scenarios that may seem to be impossible. The first application they mentioned is the editing of crops in order to be more nutritious. By editing the genes of these crops, they are capable of making them more nutritious, tastier, or even better at surviving in heat. This can also then lead to editing foods in order to make them allergen resistant, which has the potential to save lives alone.
The next possibility is the ability to stop genetic diseases by editing the human genome. This is some big money stuff, potentially leading to some quality Hollywood movie quality ideas that include possible editing of an embryo. Of course there are some HUGE ethical concerns over this idea, but it’s certainly becoming more and more of a possibility, the possibility of making the perfect child.
Aside from the designer baby ideas, there are some ideas that seem even more crazy, such as bringing a species back out of extinction, using their fossil DNA to alter similar living organisms. We are talking about bringing back the wooly mammoth here, kinda a big deal! To make a long story short, they can ensure genetic material is passed on to offspring with CRISPR instead of the 50/50 chance that they normally have.
Given all of these possibilities, it sounds like this is a topic for the future. Quite contrary actually, since it is definitely a rapidly growing AND it’s very easy and cheap. This accessibility makes it a topic to worry about now. We could use this to make designer babies OR we can use CRISPR to treat neurological genetic diseases, something like Alzheimer’s that can potentially be prevented using CRISPR. The possibilities CRISPR has to offer are endless, assuming they are used in the right way.
Plumer, Brad, et al. “A Simple Guide to CRISPR, One of the Biggest Science Stories of the
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