In this blog post, we will look at the CRISPR gene scissors technology, which is attracting attention as a life science innovation, and the ethical issues that come with it.
People who are born without genetic diseases and with predetermined physical appearance and intelligence. This is the world depicted in the movie “Gattaca.” In this movie, couples use advanced life science technology to modify the genetic information of their fertilized eggs as they wish and give birth to customized children. When this movie was released in 1997, many people thought that such a world would only be possible in the distant future. However, now there is a high possibility that such a future will become a reality in the near future, thanks to the CRISPR gene scissors technology.
CRISPR is a term that originally refers to the repetitive base sequences that are characteristic of bacteria. Many scholars have wondered why bacteria have such specific base sequences. It was not until 2005 that it was discovered that the reason bacteria have CRISPR is to prevent the invasion of external viruses. Every time a virus invades, the bacteria replicate and store a part of the virus’s base sequence. This stored sequence is useful for recognizing and attacking the virus when it invades again. The gene of the virus stored by the bacteria is the exact sequence of the CRISPR.
So how can CRISPR remove the virus? In fact, not only CRISPR but also an enzyme called “Cas9” is needed to remove the virus. Cas9 is an enzyme that has the function of cutting bases. When a virus re-enters a bacterium, the bacterium uses a pre-stored CRISPR to bind to complementary base pairs in the virus’s genes. Then, Cas9 goes to the CRISPR and cuts the genes of the virus to which the CRISPR is attached. The virus with the cut genes loses its strength and is broken down, protecting the bacterium safely.
CRISPR gene scissors are a gene scissors technology developed by applying this process. For example, if you want to remove a gene in a tomato that makes the tomato soft, you create ‘guide RNA’ by cloning the complementary sequence to the sequence before and after the gene. Then, you attach the Cas9 enzyme to the guide RNA and insert it into the nucleus where the tomato’s genes are gathered. The guide RNA binds to the front and back of the gene that makes the tomato soft, like the CRISPR of bacteria, and the Cas9 enzyme cuts it. Through this process, the tomatoes that have had the gene that makes them soft removed will not become soft over time.
Conventional gene scissors, such as zinc finger nucleases (ZFN) and TALENs, were developed by mimicking restriction enzymes found in animals and plants, making the production process complex and costly. However, CRISPR gene scissors use bacterial RNA, making them much simpler and cheaper to produce. In addition, RNA can bind to many more base pairs than restriction enzymes, making CRISPR gene scissors more delicate than ever before. This has made it possible to produce genetically modified foods and cure genetic incurable diseases that were previously impossible.
However, as technology advances, ethical issues become important. Genetic technology has been the subject of much controversy because it can touch the dignity of life. Moreover, with the advent of CRISPR, genetic technology has made great strides forward, and now we need to take a step back and look at the two aspects of technology and ethics in a balanced way. Science is like a double-edged sword. We hope that CRISPR will contribute to society by harmonizing technological progress and ethical considerations.
