By Dave DeFusco
For decades, scientists have dreamed about fixing genetic mutations, curing inherited diseases and designing crops that could feed the world. But until recently, the tools to do this were clunky, expensive and hard to use. That changed with the arrival of CRISPR-Cas9, a promising gene-editing technology that works like a molecular GPS and pair of scissors rolled into one. Scientists can program it to find a specific spot in an organism鈥檚 DNA and then cut or modify it with pinpoint accuracy.
鈥淚t鈥檚 hard to overstate how much CRISPR-Cas9 has changed the game,鈥 said Bibi Ayesa, a student in the Katz School鈥檚 M.S. in Biotechnology and Management and Entrepreneurship. 鈥淲e can now study genes in ways we couldn鈥檛 before, design targeted therapies for diseases and even re-engineer microorganisms for industrial use鈥攁ll with a level of precision that was unimaginable just 15 years ago.鈥
, led by Ayesa, published in the International Journal of Science and Research Archive explores how CRISPR-Cas9 works, the latest advances in technology and where it might take us next. CRISPR-Cas9 actually started as a bacterial defense system. Billions of years ago, bacteria evolved a way to 鈥渞emember鈥 viruses that had attacked them. They stored snippets of the viral DNA in their own genetic material, then used them to recognize and cut up matching viral DNA during future attacks.
Scientists realized they could repurpose this system. Instead of storing viral DNA, they could program CRISPR with a guide RNA that matches any DNA sequence they want to target, whether it鈥檚 in a human cell, a plant or a microbe. Once the guide RNA locks onto its target, the Cas9 protein cuts the DNA. The cell then repairs the break, which scientists can use to disrupt a gene, fix a mutation or even insert new genetic material.
Before CRISPR, tools like zinc-finger nucleases (ZFN) and transcription activator-like effector nucleases (TALENs) could edit DNA, but they were slow, expensive and difficult to customize. CRISPR only requires a small change to the guide RNA to aim at a new target, making it cheaper, faster and more flexible.
鈥淐RISPR has democratized gene editing,鈥 said Ayesa. 鈥淵ou don鈥檛 need to be a protein-engineering expert anymore. If you can design the right guide RNA connect with Cas9 protein, you can potentially edit a gene.鈥
Most people think of CRISPR as a pair of scissors that can cut DNA in just the right place. But scientists have now built new versions that work more like editing tools in a word processor. One of these tools is called a base editor. Imagine your DNA is a giant instruction manual, written with just four letters鈥擜, T, C and G. A base editor doesn鈥檛 rip out whole sentences; it acts like a pencil and eraser, quietly changing a single letter mistake into the right one. That鈥檚 important because many genetic diseases are caused by just one typo in the DNA code.
Another tool is the prime editor, which works more like the find-and-replace function on your computer. Instead of just fixing a single letter, it can rewrite short stretches of DNA with incredible precision, like swapping out the wrong word in a paragraph for the correct one.
Together, these tools take CRISPR beyond simply cutting DNA. They allow scientists to fine-tune the genetic text, correcting errors without damaging the whole page. That makes them powerful options for treating diseases caused by tiny but harmful mutations. But the technology raises big ethical questions, especially around germline editing鈥攃hanges to embryos that would be passed on to future generations.
鈥淲e have to balance this incredible potential with careful, responsible use, because this is about shaping the future of life itself,鈥 said Ayesa. 鈥淏ut with CRISPR, we finally have a way to ask鈥攁nd answer鈥攕ome of biology鈥檚 biggest questions.鈥
