What the heck is CRISPR and why did two women win a 2020 Nobel prize in chemistry for an acronym? CRISPR is a game changer. CRISPR is science that will change lives.
WHAT IS CRISPR? A GENETIC SCISSORS
CRISPR is a genetic scissors. No not Louie’s scissors! (which I had to take away, he shouldn’t be playing with scissors)
The term CRISPR comes from ‘clustered regularly interspaced short palindromic repeats’
That’s a mouthful. No wonder they came up with an acronym.
Palindromes are words, phrases, or sentences that repeat backwards or forwards, such as ‘Madam, I’m Adam.” Or the date 02/02/2020.
So the term ‘…palindromic repeat’ is –technically–redundant.
Okay, so CRISPR is a genetic scissors.
What are we cutting with the genetic scissors?
WHAT ARE GENES? WHY DO WE WANT TO CUT GENES?
Genes are a section of DNA. Long strands of DNA with lots of genes make up chromosomes.
Any given gene section along the DNA can be thought of as an instruction manual.
The gene sections have instructions encoded. The instructions allow any given cell to produce a specific product – usually a protein, such as an enzyme – that triggers one precise action.
Sometimes, these gene sections go haywire, and instruct the cells to make a product that does not help the body. Enter genetic diseases.
We need genetic disease like we need extra toes. We can cut off an extra toe. So why not cut –or silence– the gene section that isn’t doing us any good? Then our cells will stop recreating the errors.
WHAT IS CRISPR AND DNA
Lucky for us, the DNA molecule has been sequenced! We can read the cell instruction manual.
In DNA sequencing, we are determining the order of nucleotides in a strand of DNA. Nucleotides are the molecules or building blocks of DNA. (pic on right)
Every organism’s DNA consists of a unique sequence of nucleotides.
Many amazing scientists have contributed to biochemistry and genetics. There will be many more!
To find ways to treat diseases at the genetic level, is to edit them. Sorry, I sound like Yoda now.
WHAT IS GENE EDITING?
First, researchers need to modify genes in cells, so they can ascertain which segment on the DNA causes a specific disease, or which segment on a plant makes it so tasty to insects. They can’t change the gene code until they know what the code is.
This used to be time-consuming, difficult and sometimes impossible work.
2020 NOBEL PRIZE IN CHEMISTRY : Cas9 Genetic Scissors
In 2012, Emmanuelle Charpentier and Jennifer A. Doudna collaborated. They discovered one of gene technology’s sharpest tools: the CRISPR/Cas9 genetic scissors. Using these, researchers can change the DNA of animals, plants, and microorganisms with extremely high precision. This technology has had a revolutionary impact on the life sciences, is contributing to new cancer therapies, and may make the dream of curing inherited diseases come true.
CRISPR IS LIFE-CHANGING!
No wonder they were awarded a Nobel Prize.
Using the CRISPR/Cas9 genetic scissors, it is now possible to change the code of life (genes, made up of those nucleotides above) over the course of a few weeks.
CRISPR: HOW DOES IT WORK?
The genetic scissors can be used to edit a cell’s genome with incredible precision – for example, it can cut out a dysfunctional gene associated with a hereditary illness.
And if the healthy version of the gene is also delivered to the cell, the cell’s own repair system will then incorporate the healthy strands right where it was cut. Forevermore the cell with replicate the healthy code. It has a new instruction manual!
HOW DOES CRISPR GET INTO THE CELL TO CHANGE IT?
With something called a vector.
A common delivery system is…a virus! I know, seems so strange, but as we all know, viruses are excellent at getting into our cells and wreaking havoc. Scientists use only a portion of the virus –the same way they do for many vaccines <for more on the SCIENCE OF VACCINES, I have a great blog post here!> so it’s perfectly safe and the virus doesn’t cause us to become infected.
AAV is commonly used as a delivery system. It was first discovered in 1965! Big milestone!
AAV is now modified so it can get inside many different types of cells: liver, kidney, eyes, and the central nervous system.
Crossing the blood brain barrier (getting the vector into our central nervous system) is a major advancement toward the treatment of genetic diseases with gene replacement therapy.
WHAT IS CRISPR? SCIENCE THAT WILL CHANGE LIVES
I’m sure you realize now just exactly how fantastic it is to precisely speed up gene editing.
In theory, CRISPR would be able to correct diseases such as sickle cell anemia. (remember SSA is caused by a single base change /one gene gone wrong.)
Think of it like this: A technician would take (bone marrow) cells out of your body. (Bone marrow is where red blood cells are made.)
The cells would be be modified in the lab, and then put back into you. Your DNA would no longer make the sickle cells but produce normal red blood cells.
You’d be cured of that disease forever and ever—all because of a procedure you went through when you were five years old. You’re done, you’re fixed.
CRISPR & WORLD HUNGER
So CRISPR is not just about curing human diseases! It’s going to help combat world hunger. (maybe not the beer part…)
Of course there has to be a negative…
In 2018, Chinese scientist He Jiankui revealed he had helped make the world’s first gene-edited babies. His goal was to engineer resistance to infection with the AIDS virus. His work was denounced as unsafe human experimentation, and he has been sentenced to prison in China.
That can’t be fun.
The CRISPR editing I’ve discussed is done after birth, to an individual, or to crops for a higher yield, or to make food less susceptible to bacteria.
Scientists fear CRISPR will be misused to make “designer babies” via altering eggs, embryos, or sperm. These are changes that can be passed on to future generations.
Louie needs no gene therapy. He’s perfect! But if he manifested a genetic disease, he’d have CRISPR.
GENE THERAPY : A GAME CHANGER
Sure, we could write another dystopian novel about all this. In fact, I might! This science is cool and amazing. Magical!
The CRISPR/Cas9 genetic scissors has taken botany, biology, biochemistry, and genetics into a new epoch and can bring great benefits to humankind.
Trials have even shown how CRISPR delivered genetic modifications can spread through populations of mosquitoes and stop malaria infections! Imagine eliminating malaria, the way we’ve done with smallpox.
CRISPR : THE SCIENCE IS IN ACTION
And in the face of the Covid-19 pandemic, researchers have found ways to use CRISPR in rapid coronavirus diagnostic tests. Proposals have been made to use it to attack the virus’s genome.
CRISPR is used to treat acute lymphoblastic leukemia.
In 2017, the FDA approved another gene therapy for an inherited form of vision loss!
Now that you may know more about the science behind CRISPR and the Cas9 genetic scissors, what do you think about it?