Human-animal hybrid research raises hope and concern

“The 360” presents a variety of perspectives on the day’s top stories and debates.

what’s happening

Scientists have succeeded in growing embryos, including the combination of. Researchers say this is a major advance in the rapidly advancing field of genetics and could one day revolutionize the understanding of human development.

An international team of scientists, led by Juan Carlos Izpisua Belmonte of the Salk Institute for Biological Studies in La Jolla, California, injected human stem cells into monkey embryos and observed two different cell sets developing together. None of the embryos survived for more than 19 days, but experts show that this experiment represents an important advance in the science of interspecific hybrids known as chimeras.

The same scientist succeeded in using human cells to make pig and sheep embryos, but after a small portion of the cells survived in those tests, they began experimenting with primates. Researchers have found that in the near future, fully developed human-animal chimeras will provide insights into the early stages of human development, gain a better understanding of how to treat specific diseases, and even for human transplantation. I hope to donate the organs.

The science of combining the genes of two animals dates back to the 1970s. But in recent years, new technologies have brought about a series of breakthroughs. Chimera research is also controversial because of all its potential. Experiments with non-human embryos, including human cells, may be restricted in many countries, including the United States. The National Institutes of Health, the largest source of biomedical research funding in the United States, has banned the use of federal dollars for human-animal chimera research.

Why there is a debate

Due to all their promises, hybrid embryos raise ethical issues and many experts in the field have come to oppose further research. One prominent bioethicist said these experiments “open Pandora’s box” for a future in which living human and non-human hybrid animals can be fully matured, even in the early stages. .. They argue that the situation raises the question of how much human material a monkey can have before it becomes virtually human in itself.

There are also concerns about how much control can be given to which parts of the body contain human cells. For example, a chimera that contains human genetic material in the liver is far less worrisome than a chimera that contains human DNA in the brain or germ cells. Of course, some animal rights activists oppose all scientific tests on animals.

Scientists who created monkey and human embryos recognized these dilemmas and consulted with several bioethicists in developing their research. In their eyes, the potential benefits that chimeras can provide can make further research worthwhile. They say that hybrid embryos can be used in experiments that can be performed on humans for legal and moral reasons. This freedom could transform the way we understand the early stages of human development and provide insights into new treatments for chronic diseases, Belmonte said. He added that organ donations from chimeras can prevent thousands of people from dying each year in the United States alone while on the waiting list for transplants.

What’s next

Hybrid embryo research has a long way to go before any of the nasty ethical issues are tested in the real world. Next month, the International Society for Stem Cell Research will publish the latest guidelines that can set new criteria for what types of human-animal hybrid research will be accepted. The NIH says it is waiting for these new rules before deciding whether to lift the ban on funding chimera research in the United States.


Hybrid embryo research can save countless lives

“Such research should always be done carefully and properly monitored, but it should also be encouraged as the rewards it brings can prove to be important. It may provide a way to avoid ethical issues that make human embryo testing difficult. It may lead to new treatments for congenital diseases …. Long-standing global transplantable organs. Alleviating the shortage can save many lives. “— —

Chimera research creates too many nasty unknowns

“This work transcends important moral boundaries. These human monkey cells would have been neurons in the brain as well as bone and kidney tissue. In addition, we are mice and rats. Instead, we’re talking about monkeys that have a genetic affinity that is much closer to humans. What could happen from such a combination? I don’t think we should investigate. “— Wesley J. Smith,

It may not be possible to know where the line between humans and animals really stops

“Extending the concept to our own species challenges the idea of ​​human exceptionalism. What moral status could such a creature have? That human cell Does it have any effect on the development and consciousness of the animal’s brain? How can we know? ”—Oliver Duff,

At such an early stage, fear should not upset important research.

“At the time of the first plane, all potential applications existed only in the minds of a few people. It would be great for anyone if society decided that flying humans was a horrifying idea. You will miss many things that you find out. A society that sees the world as it should be, not as it should be, is an effective society that can move forward. ”—Human and animal embryo researcher Jian Feng to

Which part of the animal has human cells is very important

“The liver is a kind of liver and does not appear to have so many special properties, but sperm, eggs and brain, they are part of a person. Therefore, they are part of a person’s constituents. I feel much more ethical about growing a person in a pig, not just growing it. Someone has a heart or liver transplant, which seems a bit sensible. ”— Neuroscience researcher Francis Schen

At this stage of progress, chimera research is well within ethical scope

“I don’t think I’m particularly concerned from an ethical point of view, because I don’t have enough distance to have a nervous system or develop in any way. It really is a cell. It’s a sphere … [But] If we allow these animals to be born all the way through, and if they make a significant contribution to the central nervous system from human cells, that is clearly a concern. — Developmental Biologist Robin Lovell-Badge

Chimeras make the problem of typical animal experiments even more extreme

“These concerns about chimera research add to the already strong ethical issues associated with mainstream invasive animal research. Every year, tens of millions of animals get sick, injured, and injured in biomedical laboratories. It has been genetically engineered and killed …. Chimera research only exacerbates animal suffering and shifts it to areas of unpredictable results, whereas we are not completely ready. ” — Lori Marino,

It’s good to discuss this issue now while the research is still in its infancy

“I don’t think we are on the edge beyond” Planet of the Apes “. I don’t think there are many fraudulent scientists. But they are not zero. So I think it’s the right time for us to start thinking. “Should these go beyond the Petri dish?” — Bioethicist Hank Greeley

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