Gene Editing is not About Making Designer Babies

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Gene-editing advancements in August of 2017 raise ethical concerns that some people might want to manufacture babies that can sing like Adele, dance ballet like Baryshnikov or pitch like Cy Young. Scientists say these ideas are more science fiction than fact because talents such as these don’t belong to any one identifiable gene, but are rather a combination of genes from both parents.

First Genetic Map

Genetic engineering has some of its earliest roots in 1913, when American geneticist Alfred Sturtevant first developed a genetic map on chromosomes for his doctorate thesis. Sturtevant proved genetic linkage – the passing on of genetic material – during the cell division stage of sexual reproduction. He found that during cell division, meiosis, the number of chromosomes in parent cells reduced by half to create sperm and egg cells.

Human Genome Project

After the discovery of the double helical structure in 1953 by researchers Francis Crick and James Watson, scientists realized that a crucial step had been made to allow the full mapping of the human genome. Building on their work, Frederick Sanger discovered how to sequence DNA, determining the order of DNA’s four bases defined by chemical letters A for adenine, T for thymine, G for guanine and C for cytosine. By the 1980s, the process was fully automated.

Vision to Reality

The idea of fully mapping the entire human genome became a reality in 1988 when Congress funded the National Institute of Health and the Department of Energy to "coordinate research and technical activities related to the human genome." Expected to take decades, the project mapped nearly 90 percent of the human genome by 2000 and was fully complete in 2003, only 50 years after Crick and Watson discovered the double helix.

Base Pairs

It was discovered that the DNA bases paired similarly on opposite strands, A with T and G with C to form two base pairs. HGP identified approximately 3 billion base pairs which exist in the nucleus of our cells in 23 chromosomes pairs.

Defective Gene Editing

Fast forward to August 2017, just five years after the publishing of Crispr-9 technology that allows gene editing – known as ‘clustered regularly interspaced short palindromic repeats’ – a group of international scientists from the Oregon, California, Korea and China successfully edited a defective gene in a human embryo that passes on a congenital heart defect, hypertrophic cardiomyopathy. This defect leads to sudden death in young athletes and occurs one in every 500 people.

The international team of scientists tried two methods, one of which was more successful than the other. The first one involved eggs fertilized by male sperm carrying the defective gene. They cut out the defective male MYBPC3 gene, and injected healthy DNA into the cell with the idea that the male genome would insert the healthy template into the cut area; instead it did something unexpected. It copied the healthy cell from the female genome.

While this method worked, it only repaired 36 of 54 embryos tested. While an additional 13 embryos did not have the mutation, not all cells of the 13 were mutation free. This method did not always work, as some embryos contained both repaired and unrepaired cells.

The second method involved introducing genetic ‘scissors’ along with sperm cells into the egg cell containing mitochondrial DNA before fertilization. This resulted in a 72 percent success rate, with all 42 of 58 embryos tested being free of mutation, although 16 carried unwanted DNA. If these embryos developed into babies, and later created offspring, the defective gene would not be inherited. Embryos engineered for this study were destroyed after three days.

More Research Needed

Germline engineering doesn’t work when both parents carry the same defective gene, which is why many scientists would like to complete more trials. Under current federal law, government-based funding of scientific trials and germline engineering is not allowed, which limits the how much scientists can legally complete. The funding for the research came in part from the Institute for Basic Science in South Korea, Oregon Health and Science University, and private foundations.

Designer Babies

The idea of designer-made babies appalls many, especially when compared with the uproar about the genetic engineering of seeds and foods. But while giant steps are being made in editing defective genes, creating designer babies isn’t that easy.

Scientists posit that as many as 93,000 gene variations come into play in determining human height. Hank Greely, director of the Center for Law and the Biosciences at Stanford stated in a New York Times article, “We’re never going to be able to say, honestly, ‘This embryo looks like a 1550 on the two-part SAT,' as individual talents rise from a multitude of gene combinations."

Future of Gene Editing

At this point, scientists posit that germline engineering can greatly benefit people who want to raise a family, but are carriers of defective congenital genes. Regular Joes and Janes would more than likely not even think about gene editing and in-vitro fertilization, unless there is a specific need, as it is an expensive process and “sex is more fun,” says Dr. R. Alta Charo, a bioethicist at University of Wisconsin at Madison.

Yet, as society continues its plunge through the rapidly advancing technological era, the ethical implications of germline engineering, gene editing and designer babies will continue to be discussed and argued about for years to come.

References

About the Author

As a journalist and editor for several years, Laurie Brenner has covered many topics in her writings, but science is one of her first loves. Her stint as Manager of the California State Mining and Mineral Museum in California's gold country served to deepen her interest in science which she now fulfills by writing for online science websites. Brenner is also a published sci-fi author. She graduated from San Diego's Coleman College in 1972.