The Grapevine

Will Genetically Modified Babies Live Shorter Or Longer Lives?

On the heels of the controversial gene mutation experiment performed last year by Chinese scientist He Jiankui, a new study published in Nature Medicine by researchers at University of California, Berkeley, seeks to disprove his attempt at artificially breeding twin babies with genes resistant to HIV. 

Scientists around the world expressed discontent and regarded the experiment as incredibly unethical when the news broke last November. Jiankui used a clinically unapproved technique called the CRISPR-Cas9 to edit the CCR5 gene that lets HIV infect cells by encoding a protein. He was fired from the Southern University in Shenzhen, China, on Jan. 21 after the investigation by Guangdong Health Commission revealed he had disobeyed national Chinese regulations banning gene editing for human reproduction purposes.

The consequences of gene editing can go either way, and there is no definite way of knowing. The protein coding gene is needed for many other functions in the body, and overall health could be at risk by erasing both the copies of the gene that are present in the body naturally. 

For instance, the study conducted on CCR5-deficient mice showed that the lab rats were more susceptible to West Nile Virus (WNV). There is also evidence to suggest that altering the CCR5 gene could make people vulnerable to influenza viruses fourfold.

genetic mutation Researchers at University of California, Berkeley, found that genetic mutation of the CCR5 gene could increase risk of mortality by 21 percent. AJC, CC By 2.0

Similarly, professors of genetics at Berkeley, Rasmus Nielsen and Xinzhu Wei, have proven that people of British ancestry with the CCR5 mutation have a 21 percent higher risk of dying between the ages 41 and 78. The information was acquired from the U.K. Biobank, a database with genetic informatic on nearly half a million U.K. citizens.

Of the 409, 693 individual records accessed, it was revealed that middle aged people were better off not having the gene mutation. Two factors were considered to calculate the rate of mortality in people with the two mutated genes. The first measure related to the number of people who were not registered in the database, thus indicating they may have died earlier than those without the mutation. The second measure that was considered was the few number of people who had survived from the ages of 40 to 78.

"Both the proportions before enrollment and the survivorship after enrollment tell the same story, which is that you have lower survivability or higher mortality if you have two copies of the mutation," Nielsen said in the press release by UC Berkeley. 

The scientists are of the view that laws of natural selection intended for human beings to have the gene, since the protein is required for various functional purposes and if it were dangerous, the protein would have been destroyed by evolution naturally. 

While there are strong advocates in the scientific community who believe it's wrong to interfere with the laws of nature, there are some researchers who argue there is no other cure for HIV as of today that specifically penetrates the human immune system through the very CCR5 gene's protein Jiankui modified. 

The CCR5-∆32 mutation is found in 11 percent of Northern Europeans and is uncommon in Asians, so unfortunately Jiankui’s genetic alteration has no sample to predict its results. Only time will tell.