On spring break, we toured Warner Brothers studios with our son. Larger than life in front of the visitor center is a giant statue of Bugs Bunny, and, naturally, we had to pose for a photo. The famous cartoon rabbit is lovable because he acts like a clever, smart-alecky human being. Perhaps moms like him because he’s always munching on a carrot. Bugs Bunny’s humanesque qualities are an animator’s creation, forever locked in celluloid. But what if an actual rabbit began to have human characteristics? I’d like to talk about the present-day scenario of human-animal hybrid experiments.
“Hybrid” is a general term for organisms created by mixing species.[1] They can be created by fertilizing the egg of one species with the sperm of another species. Or, bits of human DNA can be inserted into an animal embryo. A method not allowed in the US creates a new species by a variation of cloning. A human nucleus is inserted into a rabbit egg.
These organisms serve a variety of useful purposes. They help us understand how cells behave. Will these cells develop into cancerous cells? How do cells respond to new types of drugs, especially for anti-rejection purposes in organ transplantation? We might learn if they will work to replace damaged tissue. For certain types of hybrids, the bits of human DNA help prevent tissue rejection, such as for pig valves used to treat human hearts. These are potentially beneficial purposes of biomedicine. But, there are certain questions about hybrid research that should keep us awake at night.
One of those questions is: when do we violate the barrier between human and animal species? This is a question bioethicists are struggling to answer. One Christian bioethicist argues that insertion of human DNA into a mouse egg is acceptable as long as it doesn’t change the “mouseness” of a mouse. As long as it is organized and behaves like a mouse, we haven’t acted unethically.
Another Christian bioethicist says that human brain cells should not be inserted in a mouse embryo’s brain, because the human neurons might link with the mouse neurons. The brain is an organ closely linked with our personality, and therefore we shouldn’t tamper with it.
Wait a minute. We must be careful not to draw lines based on our brain and our ability to think. That argument could be used to define human beings based on cognitive capacity, which could exclude humans with brain injuries.
This is a contemporary bioethical question that’s being worked out. We still have a voice in this conversation. As Christians, we understand that human beings truly are different from other species. Maintaining that difference is morally significant.
So, for the researchers who want to mix rabbits and humans, Bugs Bunny might say, “What’s up, Doc?” Bugs Bunny might talk like a human, but that’s because he’s imaginary. Let’s keep it that way.
[1] Technically, chimeras are not hybrids. Hybrids are offspring from cross-breeding resulting in offspring that blends the genetic inheritance from two or more species. In chimeras, a single organism is combined from cells that retain the DNA of their original species (analogous to a graft). A xenograph-pig valve inserted into a human heart mixes tissues together but does not mix pig DNA with human DNA.