Sunday, April 5, 2009

Human-to-Animal Embryonic Chimeras

Embryonic stem cell research has been debated since its creation, the controversial issue heated by the underlying topic regarding the beginning of life.  The debate remains unresolved and is becoming increasingly complex, however, as new technologies are presented.  Most recently in the United Kingdom, legislation has been passed to allow a new form of technology for deriving embryonic stem cells.  With the legislation, stem cells can be acquired by fusing the e-nucleated eggs of cows with the somatic nuclei of humans.  These human-to-animal embryonic chimeras often referred to as human-cow hybrids, have a genetic composition that is approximately 99% human and 1% bovine.  The techniques, developed to evade a shortage of human eggs, are promising to researchers hoping to make advances in regenerative medicine, and therefore, harness the potential to lessen the suffering of millions around the world.  Given this context, I will be arguing that there is currently, no concrete argument for limitations on embryonic stem cell research via human-to-animal embryonic chimeras, and in the following, hope to shine a light onto the common misconceptions instilled in many by societal constructs and norms.

When considering human-to-animal embryonic chimeras, it is important to note that the debate no longer revolves around what people believe to be the beginning of life, but instead on the morality of combining genetic material of humans with that of other animals.  Interspecies chimeras are not a new practice, however.  Animal-to-animal embryonic chimeras are regularly created within the laboratory setting, so the issue at hand is not that of simply crossing genetic material between different species, but specifically crossing human genetic material with another species.  Those who oppose this new technology do so on the grounds of repugnance and fear, neither of which hold any valid weight in ethical debate.

The commonly held Western view, known as the Great Chain of Being, establishes a hierarchy at which God is at the top, followed by angels, human beings, animals, and lastly plants.  While this view is declining in popularity with time, it is still deeply engrained within our culture, and clearly sets humans apart from all other organisms.  Along these same lines, human beings are often given a privileged place based on our higher cognitive capabilities, such as language and reason.  But are such abilities truly grounds to make this distinction?  To make such an argument, one would have to establish guidelines for species identification.  Many assume species boundaries to be determined by fixed characterizations.  Evolution being a fluid process, however, debunks this misconception. (Robert, 2003) With evolution discrediting the notion of fixed species boundaries, one cannot argue against interspecies hybrids based on categorizations that, in reality, don’t exist.

Another common objection is based upon the moral confusion introduced by creating a being with no defined moral status.  Just previously we established that, scientifically speaking, there is no such thing as fixed species boundaries.  Regardless of this fact, however, we still rely on this notion in a moral context when making decisions on how to treat creatures that differ from us, whether from what we eat to what we experimentally manipulate. It is a generally held worldview that human beings have a heightened moral status over other animals.  When creating a being that mixes two organisms of different moral statuses, however, we are faced with defining how human a being has to be to accredit it with full moral status.  Individuals who oppose human-to-animal embryonic chimeras, based on this uncertainty, do so out of fear because such a being would force us to revisit our current behaviors towards certain human and nonhuman animals.  This is not the first time we have been faced with having to determine the moral status of a being, however.  Just as we resolved the moral status of beings that are undeniably human (women, African Americans, and the like), we can rest assure that the same will be resolved for any beings we create. (Robert, 2003)

There are a multitude of other objections that appear to be variations of the ones discussed above.  Accepting that species boundaries are social constructs rather than scientific truths, however, refutes the majority of these objections.  By recognizing evolution as a fluid process in which species are ever changing, we have no reason to limit technology that harnesses potential to lessen the pain and suffering of all beings around the world.

Works Cited:

Robert, Jason Scott. (2003). Crossing Species Boundaries. The American Journal of Bioethics, Volume 3, Number 3, Summer 2003, pp. 1-13. Retrieved on March 31st, 2009 from bioethics/v003/3.3robert.pdf


  1. The video is very interesting and I agree with Dr. Ruth Faden (i believe is her name). If this was introduced in the United States then there will be a great number of people who find this disturbing and unacceptable. However, I believe that if scientists can get the news out about it what exactly is going on then there would be a greater acceptance of the method.

    I believe that part of the problem is the name of the embryo. Human-cow hybrid gives little information about what exactly it is and at first, I pictured something like a centaur if the embryo was allowed to fully develop.

    However, from my understanding, the only part of the embryo that is an animal part is the egg shell since the DNA is sucked out and the human DNA is injected and many people may not understand that at first.

    This could lead to a great variety of accomplishments as well as concerns. I beleive that the accomplishments would greatly out weigh the concerns as long as people do not try to go overboard with the research. This could help so many people who are currently fighting for their lives because they need an organ transplant, suffer from an incurable disease or who are witnessing their love ones go through such things. However, the part that I would have a problem with is if we allowed this type of embryo to develop because we do not know what exactly would come of it. I think that it would be unethical for scientists to one day try to develop on of the human-cow embryos just because they would want to see what develops. No one knows what to expect and if it did develop safely, how would we know if it would have a good life, or would develop normally.

  2. Just to clarify, there is a small amount of genetic material coming from the other organism in the form of mitochondrial DNA (mtDNA). mtDNA is located in the cytoplasm of the egg, and is thought to be of a different evolutionary lineage than nuclear DNA. mtDNA is proposed to have evolved from the circular DNA of bacteria that was engulfed by early eukaryotic cells. Despite this difference, mtDNA still codes for genes (37 in mammals), including 13 proteins, and the remaining coding for tRNA and rRNA. Therefore, the mtDNA of the cow egg would have a genetic influence on the embryo if it were to develop (which would NOT be occurring in the proposed techniques).
    Furthermore, I agree that the idea of allowing such an embryo to develop for mere curiosity would be unethical, but only because the intent in doing so would be as a form of entertainment for those involved in the process. However, if such an organism were to develop with a more morally acceptable intent, I do not see any such harm in doing so. Human beings have the tendency to stigmatize the human race to be apart from other animals, but I would argue this to be a falsehood. We are an animal just like any other, albeit with more complex cognitive abilities. Furthermore, you could argue that we are just as any other organism (animal, plant, bacteria, etc.) faced with the same basic struggle that all organisms face - passing on one's genetic information to future generations.
    Interspecies reproduction occurs all the time in nature and it is silly for us to feel repulsed at the notion of a partial human being. I think any feelings of repulsion are misconstrued emotions, and that human beings may more accurately feel threatened by the notion. What if the creature we created were some super-being? What would happen to the human race as we know it? Could we be overcome by a superior race? And more so, what would this mean for our genetic information that we are trying to pass on, considering that none of us are trying to procreate with another species? In other words, I see feelings of "repulsion" as misinterpreted feelings of threat to our offspring. Is this selfish? Is it fair for us to try and hold evolution at a standstill in the name of preserving our species?
    This is merely my interpretation, however. Thoughts?

  3. I happen to disagree with you. Humans may be animals, however i feel that they are advanced animals. We have greater ability to do many different tasks such as increased reasoning, intelligence and our spectrum of feelings. I do not disagree that animals have feelings however I feel that our feelings are more complex and advanced when compared to the feelings of animals.

    Humans have the ability to think logically about a situation and use their knowledge to make decisions about future situations. Animals however, have to learn by experience to be able to make such decisions (humans sometimes use this method as well but do not necessarily have to because they can use the experiences of others).

    Additionally, I feel that as humans, we tend to feel superior partly because we have the ability to buy, sell, and take care of animals. Animals can not do the same for humans.