Many fictions have warned us about the dangers of playing God with human genetics, but sadly, what’s going on these days isn’t fiction.
Just in the last few years, many news stories have described how researchers are creating embryos that are part human and part animal.
While many countries around the world have restricted, defunded, or outright banned these ethically fraught practices, Japan has now officially lifted the lid on this proverbial Pandora’s box. The government has said that experiments like these can take steps to prevent the birth of a creature that contains a mix of animal and human genetics. Japan had previously banned such experiments.
Stem cell biologist Hiromitsu Nakauchi has been waiting for this moment for more than a decade. A Japanese stem-cell scientist is the first to receive government support to create animal embryos that contain human cells and transplant them into surrogate animals since a ban on the practice was overturned earlier this year. Nakauchi says he plans to proceed slowly, and will not attempt to bring any hybrid embryos to the term for some time.
Initially, he plans to grow hybrid mouse embryos for 14.5 days, when the animal’s organs are mostly formed, and it is almost to term. He will do the same experiments in rats, growing the hybrids to a near term, about 15.5 days. Later, Nakauchi plans to apply for government approval to build hybrid embryos in pigs for up to 70 days.
Many other countries have experimented on creating human-animal embryos, and Japan is now the first country to support experiments that will allow the animals with human cells to come to full term. Scientists in the United States have experimented with pig-human hybrid and allowed them to develop for three to four weeks before destroying them, as required by US ethics regulations.
Purpose of such experiments
The purpose of human-animal hybrid is ultimately to help save the lives of people with a wide range of diseases. As per the researchers, the “chimera embryos” might be used to create better animal models to study how human diseases happen and how they progress. The goal is for the stem cells to “take advantage of the void in the embryo and start forming a human pancreas.” This human pancreas can then be transplanted into a human recipient with less chances of rejection.
One of the main concerns with this type of research is precisely where these human stem cells actually go in an animal, and what kind of cells they could develop into after they are injected.
Nakauchi and his team are trying to target this treatment to just the pancreas; if they detect more than 30 percent of the rodent brains are human, they will suspend the experiment. These are part of the government’s conditions to prevent a “humanized” animal from ever coming into existence. But this couldn’t be with every experiment.
Concerns over these Experiments
It doesn’t make sense to bring human-animal hybrid embryos to term using evolutionarily distant species such as pigs and sheep because the human cells will be eliminated from host embryos early on, says Jun Wu, who researches human-animal chimeras at the University of Texas Southwestern Medical Centre in Dallas.
“Understanding the molecular basis and developing strategies to overcome this barrier will be necessary to move the field forward,” Wu says.
Stuart Newman, a professor of cell biology at New York Medical College told NPR that the technology takes us “into unsettling ground that I think is damaging to our sense of humanity.” It’s not the first time Newman has taken on the issue. Newman’s Wikipedia biography calls him “an outspoken critic of proposed uses of developmental biology to modify human species identity, including cloning and germline genetic manipulation.” In 1997, he applied for a patent on human-animal chimera just to raise the moral and legal questions surrounding the technology.
“It is problematic, both ethically and from a safety aspect, to place human cells, which are still capable of transforming into all types of cells, into the fertilized eggs of rats and mice,” said Jiro Nudeshima, a researcher specializing in the ethical implications of life science research.
What if scientists create chimeras capable of producing human gametes? There might be some risk that sex between chimeric animals could result in human pregnancy.
Is it against nature?
Many of us are like five-year-olds who turn their nose up at the idea of mixing even their broccoli with their mashed potato. We prefer to keep things pure. Whether it is cross-bred animals or racially mixed children, people who see the world as defined by underlying essences tend to reject such impurity.
“Mixing up human and animal biology is perceived as being unnatural.”
We all are made of different combinations of the same kinds of stuff. Even much of the blueprint and DNA are shared across species, such that humans and mice share around 90% of their DNA, and we also share approximately 90% of their DNA, and we even share about 35% of our genes with the simple roundworm. Mixing human and animal biology is perceived as being unnatural, creating an irrational fear that human-pigs might escape the research area and take over the world. Just like the Greeks, our fear of hybrids fosters the sense that such creatures would be monstrous.
The world needs to rethink these laws, or, failing that, we should introduce alternative forms of regulation that can prevent unethical forms of chimera research. We should not ignore important ethical concerns.
Are we ready to accept such experiments?
Will you ever accept an organ from an animal body?