US researchers are now editing human embryos using CRISPR

28 Jul 2017

Image: Nixx Photography/Shutterstock

Reports in the US of genetically modified human embryos are the latest in a long line of CRISPR-led achievements.

Following in the footsteps of earlier studies and attempts in China, researchers in the US are the latest to efficiently improve the DNA of human embryos.

Using the potentially era-defining CRISPR technology, a team led by Shoukhrat Mitalipov of Oregon Health and Science University is said to have successfully proven the process.

Future Human

According to MIT Technology Review, Mitalipov and his team changed the DNA of “a large number of one-cell embryos”, paving the way for a process to safely and efficiently correct defective genes that cause inherited diseases.

Exactly how many embryos, and what genes were targeted, is unclear at this stage – however, the embryos were only allowed to develop for a few days and were never implanted into a womb, according to the report.

Ethical dilemma

Perhaps unlike any other method of gene editing, CRISPR has captured the imagination of the public.

CRISPR is a technique that allows geneticists to search for, find and then zoom in on specific DNA sequences, slice out genes and edit them, before returning them into their original sequence.

So, in theory, the gene that leads to the development of Huntington’s disease later in life can be cut out and replaced with a healthy gene, thereby ending thousands of years of natural genetic evolution.

It’s a relatively new and definitely groundbreaking process, and utilising it on embryos puts it at the centre of an ethical dilemma for scientists: will this lead to ‘designer babies’?

“I think one has to exercise a certain amount of caution, and I think there are a lot of reports out there of the speed at which it is being deployed in biological systems in human patients,” DCU researcher Dr Andrew Kellett recently told

“From my point of view, it is very exciting, but that has to be balanced with a long-term view of the ethics and also the potential side effects from some of these, and they won’t be seen for a long number of years.”

However, some side effects have already emerged.

Recent research conducted by Columbia University Medical Center revealed startling evidence that CRISPR creates hundreds of unintended mutations in the genome.

Published in Nature Methods, the research looked at sequencing the entire genome of mice that had previously undergone CRISPR gene editing and analysed any mutations down to a single nucleotide.

While the researchers identified that CRISPR had corrected the gene that leads to blindness in mice, they also found that hundreds of genes had been altered.

CRISPR around the world

In 2015, CRISPR got far more affordable, while researchers also worked out how to edit human T-cells, which play a key role in diseases such as diabetes and cancer.

It is through this prism that a team from Temple University Health System found a way to fight back against HIV last year, essentially ‘cutting’ out the problem.

A few years ago, amid horror stories of the catastrophic damage caused by GMOs accidentally entering an environment where they could cause havoc, a new ‘kill switch’ was developed using CRISPR to prevent that happening.

Elsewhere, live cows with increased tuberculosis resistance have been developed by Chinese researchers.

Gordon Hunt was a journalist with Silicon Republic