Chinese team uses CRISPR to genetically modify human embryo

April 11, 2016 by Bob Yirka report
Human Embryo. Credit: Ed Uthman, MD/Wikipedia

(Medical Xpress)—A team of researchers at Guangzhou Medical University in China has published a paper in the Journal of Assisted Reproduction and Genetics describing their efforts to genetically modify a human embryo using CRISPR/Cas9, the gene editing technique. The research, the team reports, was carried out on embryos that carried an extra set of chromosomes, and thus were not viable.

Doing any sort of genetic modification on is, of course, quite controversial—most medical researchers believe that one day such practices will be common, but today, so much is still unknown regarding the consequences of such procedures that most of the world has decided to hold off doing such research until much more has been learned. Indeed it was just a year ago that a different team in China published results of another study that involved editing human embryo genes, causing a stir in both the medical and ethical community.

In this latest effort, the Chinese team reports that they obtained 213 fertilized eggs from a fertility clinic, which had been deemed unsuitable for in vitro therapy. The women who had donated the eggs all gave permission for the embryos to be used for genetic research, on condition that the embryos would not be allowed to mature into a human being. The team used the CRISPR technique to edit genes, adding a mutation that causes damage to an immune cell gene called CCR5—such cells that are damaged naturally have been found to lead to HIV resistance. Thus the point of the research was to learn more about the possibility of producing human babies that would be immune to HIV. The team reports that just 4 out of 26 of the embryos that were edited were modified successfully—some still contained genes that had not been modified, and others had resulted in unexpected gene mutations. All of the embryos were destroyed after three days. Due to the results, it is not clear what has been learned from the experiments, except that some groups, particularly in China, are willing to conduct such research despite international condemnation.

It is likely that news of the work done by the team in China will spark a new round of discussions regarding such research, and others will no doubt condemn the team for what they have done—but the researchers are neither apologizing nor backing down—instead they suggest that such research is paving the way for future efforts while also noting that they have no intention of allowing genetically modified to mature—once the rest of the world is ready to join them, they suggest, a path for moving forward will have already been laid.

Explore further: Chinese team performs gene editing on human embryo

More information: Xiangjin Kang et al. Introducing precise genetic modifications into human 3PN embryos by CRISPR/Cas-mediated genome editing, Journal of Assisted Reproduction and Genetics (). DOI: 10.1007/s10815-016-0710-8

Abstract

Purpose
As a powerful technology for genome engineering, the CRISPR/Cas system has been successfully applied to modify the genomes of various species. The purpose of this study was to evaluate the technology and establish principles for the introduction of precise genetic modifications in early human embryos.
Methods
3PN zygotes were injected with Cas9 messenger RNA (mRNA) (100 ng/μl) and guide RNA (gRNA) (50 ng/μl). For oligo-injections, donor oligo-1 (99 bp) or oligo-2 (99 bp) (100 ng/μl) or dsDonor (1 kb) was mixed with Cas9 mRNA (100 ng/μl) and gRNA (50 ng/μl) and injected into the embryos.
Results
By co-injecting Cas9 mRNA, gRNAs, and donor DNA, we successfully introduced the naturally occurring CCR5Δ32 allele into early human 3PN embryos. In the embryos containing the engineered CCR5Δ32 allele, however, the other alleles at the same locus could not be fully controlled because they either remained wild type or contained indel mutations.
Conclusions
This work has implications for the development of therapeutic treatments of genetic disorders, and it demonstrates that significant technical issues remain to be addressed. We advocate preventing any application of genome editing on the human germline until after a rigorous and thorough evaluation and discussion are undertaken by the global research and ethics communities.

Related Stories

Chinese team performs gene editing on human embryo

April 23, 2015
(Phys.org)—A team of researchers in China has announced that they have performed gene editing on human embryos. In their paper uploaded to the open access site Protein & Cell (after being rejected by Nature and Science) ...

Should scientists be allowed to genetically alter human embryos?

July 1, 2015
Scientists have at their disposal a way to explore the possible prevention of genetic diseases before birth. But should they? Currently, the most promising path forward involves editing the genes of human embryos, a procedure ...

Britain allows first genetic modification of embryos (Update 2)

February 1, 2016
Britain on Monday granted its first research licence to genetically modify human embryos to a project that aims to give hope to women struggling to conceive, raising ethical concerns about "designer babies".

Recommended for you

New approach to studying chromosomes' centers may reveal link to Down syndrome and more

November 20, 2017
Some scientists call it the "final frontier" of our DNA—even though it lies at the center of every X-shaped chromosome in nearly every one of our cells.

Genome editing enhances T-cells for cancer immunotherapy

November 20, 2017
Researchers at Cardiff University have found a way to boost the cancer-destroying ability of the immune system's T-cells, offering new hope in the fight against a wide range of cancers.

A math concept from the engineering world points to a way of making massive transcriptome studies more efficient

November 17, 2017
To most people, data compression refers to shrinking existing data—say from a song or picture's raw digital recording—by removing some data, but not so much as to render it unrecognizable (think MP3 or JPEG files). Now, ...

Genetic mutation in extended Amish family in Indiana protects against aging and increases longevity (Update)

November 15, 2017
The first genetic mutation that appears to protect against multiple aspects of biological aging in humans has been discovered in an extended family of Old Order Amish living in the vicinity of Berne, Indiana, report Northwestern ...

US scientists try first gene editing in the body

November 15, 2017
Scientists for the first time have tried editing a gene inside the body in a bold attempt to permanently change a person's DNA to try to cure a disease.

Genetic variant prompts cells to store fat, fueling obesity

November 13, 2017
Obesity is often attributed to a simple equation: People are eating too much and exercising too little. But evidence is growing that at least some of the weight gain that plagues modern humans is predetermined. New research ...

3 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

NoStrings
3.7 / 5 (3) Apr 11, 2016
Much needed research. The critics may discuss away, and oppose all they want, but it is simple: it is unethical not to pursue this research.
richardnunziata
4.8 / 5 (4) Apr 11, 2016
This why we need to take such research off shore. Ideas like Seasteading will allow research to move forward without government and moralist interference.
dedereu
1.8 / 5 (5) Apr 12, 2016
CRISPR gives a beginning to modify all the living organisms without knowing the huge complexity behind 4 billions years of evolution of life.
This is very dangerous !!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.