Thread by @realscientists

CRISPR is the coolest thing you’ll learn about today. Let’s dive into the science first, look at some actual applications and finally discuss the ethics and how far are we from a genetically engineered future.

The technology has been in the making for nearly 20 years, and many scientists have played a role in understanding of key steps in the process that eventually led to the nobel prize winning discovery. Here’s a handy guide on the timeline
bitesizebio.com/47927/history-…

To understand gene editing with CRISPR, we need to first appreciate the beauty of the bacterial immune system. Just like us, they have a way to remember attacks by viruses, so that they can fight off the virus next time they get attacked.

When a bacteria fights off a virus attack, it breaks the virus down into small fragments and store these fragments inside the its DNA. Think of it like a mugshot for each virus attack. These are stored in sequences that repeat throughout the bacteria’s DNA.

These repeated sequences are what are known as CRISPR or Clustered Regularly Interspaced Short Palindromic Repeats. Over its lifetime, the bacteria accumulates a book of mugshots that will help identify and destroy future viral attacks.

When encountering another virus, the bacteria will produce a special protein known as Cas9, that not only carries this book of mugshots, but can check if there’s a match. And if there is, the Cas9 can chop it into bits and get rid of it!

Sure this is cool, but how can this edit genes? See, when looking more at how this whole CRISPR-Cas9 system worked, they figured out that they could actually give any RNA to the Cas9 protein, so its like inserting anyone’s picture in the mugshot book. What does this mean?

We now suddenly have the capability to target the Cas9 protein to any part of a DNA sequence, where it can edit out unwanted genes. Editing genomes till then was expensive and prone to errors, so when it was shown this could be done in human cells, there was tangible excitement!

And now we have researchers all over the world using this tech for everything from diagnostics to healthcare, from the dairy industry to bringing back extinct animals, from eliminating harmful genetic mutations to introducing new traits in people.

Let’s forget about editing human embryos for a sec,yes it is incredibly important to think of the moral questions and ethical debates, but it tends to dominate the chatter. This tool is incredibly powerful and can be used in SO many ways that are less permanent than CRISPR babies

Something beautiful CRISPR helped discover was the painting gene in butterflies. By cutting out this gene, they were able to follow the color and pattern formation of butterflies all the way from the caterpillar stage. bit.ly/2Quw0A9

Think about if we could eradicate malaria and the millions of lives it could save. Gene editing can be used to create engineered mosquitos 🦟that can no longer spread malaria. Or we could be more drastic and reduce the mosquito population. Which one would you prefer?

Bacteriophages, viruses that attack bacteria, are a HUGE problem for the dairy industry. So they’ve been using CRISPR methods for over a decade to produce stronger starter cultures with healthy bacteria that can eliminate viral infections.
the-scientist.com/notebook/there…

High yield, disease resistant crops using less water? Non-browning mushrooms and apples, high yield tomatoes, allergy free food, these are all already being developed using gene editing and are in different stages of being commercialized. bit.ly/3vUobnM

Are they genetically modified? Yes, but using a more precise technique that DOES NOT introduce foreign DNA, which is part of why there is massive resistance to GMO produce even if its safe. Instead, these plants have specific genes inserted or removed for specific traits.

And then of course designer babies, but not for eye color or height, but for eliminating deadly diseases like sickle cell anemia and cystic fibrosis. There are close to 50 clinical trials being run in different parts of the world already to treat rare and hard-to-treat diseases.

The first patient was injected with CRISPR edited cells in 2016 for the treatment of aggressive lung cancer. The issue with most approaches still is they can’t modify enough cells for the treatment to be effective. But these hurdles can be overcome. go.nature.com/3vTqJ5B

Some of the really exciting companies to watch in this space are @CRISPRTX @BeamTx @intelliatweets @mammothbiosci @eGenesisBio @SynGenomeInc @plantedit @CaribouBio @editasmed @VerveTx

Unroll please @threadreaderapp