Researchers at the University of California, Davis are looking to create human-animal hybrid embryos known as chimeras, which they believe could serve as better animal models for studies on how people develop diseases and how these illnesses progress.

In Greek mythology, the chimera was a monstrous creature that was created using parts of different animals such as a lion, a goat and a snake.

A chimera in genetics, on the other hand, is a single organism produced through the combination of cells from different zygotes, or fertilized eggs.

While earlier studies have explored the potential benefits of developing plant and animal chimeras, research on the use of human cells for the practice is strictly prohibited by many world governments. They believe creating chimeras using human and animal cells violates the dignity of being human.

UC Davis undergraduate students John Powers and Ryan Troy have studied the merits of creating human-animal hybrids in their paper "Human-Animal Chimeras: What are we going to do?"

In exploring the ethics behind creating human-animal chimeras for research, Powers and Troy explained that the gene-editing method might not pose a threat to human dignity.

Some scientists claim that experiments on chimeras could be used to develop human organs grown in farm animals, which could then be transplanted into patients with terminal illnesses.

However, bioethicists and other scientists have expressed their concern that creating interspecies embryos could blur the ethical line between what is human and what is not.

Cell biology professor Stuart Newman from the New York Medical College pointed out that such experiments venture into unsettling ground that is damaging to people's sense of humanity.

For its part, the National Institutes of Health (NIH) has placed funding for chimera experiments on hold to allow officials to examine the ethical issues raised regarding the practice.

Some researchers are pushing through with their studies through the help of alternative funding in the hope that their findings could convince the NIH to remove the moratorium.

One of the scientists is reproductive biologist Pablo Ross from UC Davis, who is applying gene-editing techniques to develop human pancreas through the use of pig embryos.

"We're not trying to make a chimera just because we want to see some kind of monstrous creature," Ross said. "We're doing this for a biomedical purpose."

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