‘Behold, a flawless human!’ We are going to hear a lot of molecular biology researchers and scientists use this phrase in the future if the CRISPR tool technique gets approved. For those of you who might have heard the term CRISPR quite recently or those, who have no clue what it means, let me briefly define it this way: its a magic trick discovered by scientists to modify human DNA. Yes, I know it sounds pretty science fiction but, its true. We finally have a means or technique that can change the human DNA and modify it for better or worse.
“With great power, comes great responsibility”, and so, there is a moral dilemma associated with the use of this technique. Whether it will be used for the good of humanity or to create deadly weapons is the question that scientists are debating on. The technique was first discovered by Japanese scientists while they were trying to study the DNA of E.coli bacteria in the year 1987. In a particular protein encoding gene of the E.Coli bacteria, they noticed a pattern of short, repeating, palindromic DNA sequences separated by short, non-repeating, “spacer” DNA sequences.
In the next few years, researchers noticed this pattern in other bacteria and single celled organisms. They coined the term CRISPR – “clustered regularly interspaced short palindromic repeats,” to describe the pattern. Further research showed that repeating DNA patterns, along with a family of “Cas” (CRISPR-associated) proteins and specialized RNA molecules, play a role in the immune system of bacteria. They named the entire complex of DNA repeats, Cas proteins, and RNA molecules as the CRISPR/Cas system. The way CRISPR/Cas work in bacteria is by copying and incorporating segments of foreign DNA (e.g virus) into their genome as “spacers” between the short DNA repeats in CRISPR. So that, in case of a virus attack the RNA molecules can use this template to identify and target the same DNA sequence. The Cas proteins of the bacteria are specialized for cutting DNA, splicing and disabling the foreign gene.
Over the past few years, researchers have explored many different applications of CRISPR/Cas9 that include, genetically modifying crops, eradicating viruses, screening for cancer genes, and—the subject of much recent debate—genome engineering. In the fall of 2012, a team of researchers led by UC Berkeley scientists Jennifer Doudna and Emmanuelle Charpentier announced that they had hijacked the bacteria’s CRISPR/Cas immune system to create a new gene-editing tool. Their CRISPR/Cas9 system involved CRISPR, a Cas protein called Cas9, and hybrid RNA that could be programmed to identify, cut, and even replace any gene sequence. Scientists have recently announced that they have been successful in using this technology to inhibit hepatitis C in human cells thus defying Mendel’s laws of inheritance, which have governed the field of genetics for over a century.
As we can see, this technology has great power to change the genetic make up of humans and so it is very essential that it is used cautiously. If scientists are able to narrow down the use of CRISPR/Cas9 in human germ cells, it could eradicate hereditary diseases such as cystic fibrosis, sickle-cell anaemia, and Huntington’s disease from a family line altogether.
It’s also necessary, however, to consider another logical conclusion—that people might want to use gene-editing techniques to create humans with super strength, hyper-intelligence, or whatever other genetic traits people might desire. For good reason, such possibilities trigger fears of eugenics and designer babies. For now, we do not have the answers to such scientific and philosophical questions that surround CRISPR/Cas9 . One thing is clear though, we are progressively moving towards a future in which CRISPR/Cas9 will have a critical role.