why in news?
- Recently, the Chinese scientist who created the world’s first gene-edited babies has forced researchers everywhere to take a hard look at the ethics of gene-editing.
Background of this scenario :
- Chinese authorities have condemned the researcher, He Jiankui, with a government report this week saying he violated both ethics and laws.
- Though Mr. He’s actions drew international outrage, they weren’t revolutionary in technological terms.
- Editing DNA to correct disease mutations has been possible for a while now, which means others can also do what the Chinese scientist did.
Promises and Challenges in Gene editing :
- The promises of such gene-editing are boundless.
- Over a dozen clinical trials are currently on to treat diseases like HIV, multiple myeloma and other forms of cancer, using the Crispr-Cas9 editing system.
- But none of them involve editing the so-called human germ-line.
- Instead, they have restricted themselves to fixing genetic flaws in sick adults.
What the Chinese scientist did in editing gene ?
- In contrast to the above, the Chinese scientist deactivated a gene in two human embryos, which means that the changes he made could be inherited by the next generation.
- In doing so, he violated the widely held ethical consensus that it is too early for germline editing, for we simply don’t know enough yet about the risks of such fiddling.
(a) Not as precise: One pitfall of embryo gene-editing is that it is not as precise as we need it to be today.
(b) Can result in unintended mutations: Studies have shown that the technology can result in unintended mutations, which in turn can cause cancers.
(c) Danger of mosaicism: In which some cells inherit the target mutation, while others don’t.
Caution over embryo gene editing
- However, the error-rates of Crispr are falling with each passing year. But the scientists aren’t in the clear yet.
- Even when gene-editing becomes fool-proof, the decision to edit embryos will still be a weighty one.
- This is because, today, scientists are far from understanding how exactly individual genes influence phenotypes, or the visible traits of people.
- Every gene likely influences multiple traits, depending on the environment it interacts with.
- This makes it hard to predict the ultimate outcome of an embryo-editing exercise without decades of follow-up.
- This uncertainty became evident in Mr. He’s experiment, in which he sought to immunise a pair of twins from HIV by tinkering with a gene called CCR5.
- The problem is that while protecting against HIV, a deactivated CCR5 gene can also make people more susceptible to West-Nile Fever.
- Every gene influences such trade-offs, which scientists barely understand today.
- This is why several scientific societies have advised abundant caution while fiddling with the human germline.
- In a 2017 report, the U.S.’s National Academies of Sciences, Engineering, and Medicine said such an intervention would be defensible only in very rare situations, where no alternative exists.
- In Jiankui incident shows it is time to translate these advisories into regulations.
- Unless this happens, the Crispr revolution could well go awry.
What are Genes and Gene- editing?
Genes contain the bio-information that defines any individual. Physical attributeslike height, skin or hair colour, more subtle features and even behavioural traits can be attributed to information encoded in the genetic material. An ability to alter this information gives scientists the power to control some of these features.
- Genome editing/gene editing, is a group of technologies that give scientists the ability to change an organism’s DNA. These technologies allow genetic material added, removed, or altered at particular locations in the genome.
- In addition to , several approaches to genome editing have been developed. A recent one is known as CRISPR-Cas9, which is short for Clustered Regularly Interspaced Short Palindromic Repeatsand CRISPR-associated protein 9.
- Moreover, The CRISPR-Cas9 system is faster, cheaper, more accurate, and more efficient than other existing genome editing methods.
- It is a unique technology that enables to edit genome by removing, adding or altering sections of the DNA sequence.
- CRISPRs specialized stretches of DNA. The protein Cas9 is an enzyme that acts like a pair of molecular scissors, capable of cutting strands of DNA. It allows researchers to easily alter DNA sequences and modify gene function.
- It is the simplest yet powerful tool for editing genomes . Moreover , it termed as the most versatile and precise method of genetic manipulation.