Human–animal hybrid

The terms human–animal hybrid and animal–human hybrid refer to an entity that incorporates elements from both humans and non-human animals. Technically, in a human–animal hybrid, each cell has both human and non-human genetic material, whereas an individual where some cells are human and some are derived from a different organism is called a human-animal chimera.

Examples of human–animal hybrids mainly include humanized mice that have been genetically modified by xenotransplantation of human genes. Humanized mice are commonly used as small animal models in biological and medical research for human therapeutics.

Human-animal hybrids are the subject of legal, moral, and technological debate in the context of recent advances in genetic engineering.

Human–animal hybrids exist throughout social cultures for a long time (particularly in terms of mythology), being part of storytelling across multiple continents and particularly have been incorporated into comic books, films, video games, and related such mass media in recent decades.

Terminology

Defined by the magazine '' H+'' as "genetic alterations that are blendings icof animal and human forms", such hybrids may be referred by other names occasionally such as "para-humans". They may additionally may be called "humanized animals". Technically speaking, they are also related to "cybrids" (cytoplasmic hybrids), with "cybrid" cells featuring foreign human nuclei inside of them being a topic of interest. Possibly, a real-world human-animal hybrid may be an entity formed from either a human egg fertilized by a nonhuman sperm or a nonhuman egg fertilized by a human sperm.

Throughout past human evolution, there has been interbreeding between archaic and modern humans. For example, Neanderthal genes accounts for 1–4% of modern human genomes for people outside Sub-Saharan Africa. However, as archaic humans may not be classified as animals, such interbreeding is generally not classified as human–animal hybridization.

Examples

Artificially created human-animal hybrids include humanized mice that have been xenotransplanted with human gene products, so as to be utilized for gaining relevant insights in the ''in vivo'' context for understanding of human-specific physiology and pathologies. Humanized mice are commonly used as small animal models in biological and medical research for human therapeutics including infectious diseases and cancer. For example, genetically modified mice may be born with human leukocyte antigen genes in order to provide a more realistic environment when introducing human white blood cells into them in order to study immune system responses.

Moral discussions

Advances in genetic engineering have generally caused a large number of debates and discussions in the fields related to bioethics, including research relating to the creation of human-animal hybrids. Although the two topics are not strictly related, the debates involving the creation of human-animal hybrids have paralleled that of the debates around the stem-cell research controversy.

The question of what line exists between a 'human being and a 'non-human' being has been a difficult one for many researchers to answer. While animals having one percent or less of their cells originally coming from humans may clearly appear to be in the same boat as other animals, no consensus exists on how to think about beings in a genetic middle ground that have something like an even mix. "I don't think anyone knows in terms of crude percentages how to differentiate between humans and nonhumans," U.S. patent office official John Doll has stated. Critics of increased government restrictions include scientists such as Dr. Douglas Kniss, head of the Laboratory of Perinatal Research at Ohio State University, who has remarked that formal laws aren't the best option since the "notion of animal-human hybrids is very complex." He's also argued that their creation is inherent "not the kind of thing we support" in his kind of research since scientists should "want to respect human life".

In contrast, notable socio-economic theorist Jeremy Rifkin has expressed opposition to research that creates beings crossing species boundaries, arguing that it interferes with the fundamental 'right to exist' possessed by each animal species. "One doesn't have to be religious or into animal rights to think this doesn't make sense," he has argued when expressing support for anti-chimera and anti-hybrid legislation. As well, William Cheshire, associate professor of neurology at the Mayo Clinic's Florida branch, has called the issue "unexplored biologic territory" and advocated for a "moral threshold of human neural development" to restrict the destroying a human embryo to obtain cell material and/or the creation of an organism that's partly human and partly animal." He has said, "We must be cautious not to violate the integrity of humanity or of animal life over which we have a stewardship responsibility".

Legality

While laws against the creation of hybrid beings have been proposed in U.S. states and in the U.S. Congress, several scientists have argued that legal barriers might go too far and prohibit medically beneficial studies into human modification.

In terms of scientific ethics, restrictions on the creation of human–animal hybrids have proved a controversial matter in multiple countries. While the state of Arizona banned the practice altogether in 2010, a proposal on the subject that sparked some interest in the United States Senate from 2011 to 2012 ended up going nowhere. Although the two concepts are not strictly related, discussions of experimentation into blended human and animal creatures has paralleled the discussions around embryonic stem-cell research (the 'stem cell controversy'). The creation of genetically modified organisms for a multitude of purposes has taken place in the modern world for decades, examples being specifically designed foodstuffs made to have features such as higher crop yields through better disease resistance.

President George W. Bush brought up the topic in his 2006 State of the Union Address, in which he called for the prohibition of "human cloning in all its forms", "creating or implanting embryos for experiments", "creating ''human-animal hybrids''", and also "buying, selling, or patenting human embryos". He argued, "A hopeful society has institutions of science and medicine that do not cut ethical corners and that recognize the matchless value of every life." He also stated that humanity "should never be discarded, devalued or put up for sale."

A 2005 appropriations bill passed by the U.S. Congress and signed into law by President Bush contained specific wording forbidding any patents on humans or human embryos. In terms of outright bans on hybrid research in the first place, a measure came up in the 110th Congress entitled the ''Human-Animal Hybrid Prohibition Act of 2008''. Congressman Chris Smith ( R, NJ-4) introduced it on April 24, 2008. The text of the proposed act stated that "human dignity and the integrity of the human species are compromised" if such hybrids exist and set up the punishment of imprisonment for up to ten years as well as a fine of over one million dollars. Though attracting support from many co-sponsors such as then Representatives Mary Fallin, Duncan Hunter, Joseph R. Pitts, and Rick Renzi among others, the Act failed to get through Congress.

A related proposal had come up in the U.S. Senate the prior year, the ''Human-Animal Hybrid Prohibition Act of 2007'', and it also had failed. That effort was proposed by then-Senator Sam Brownback ( R, KS) on November 15, 2007. Featuring the same language as the later measure in the House, its bipartisan group of cosponsors included then Senators Tom Coburn, Jim DeMint, and Mary Landrieu.

A localized measure designed to ban the creation of hybrid entities came up in the state of Arizona in 2010. The proposal was signed into law by then Governor Jan Brewer. Its sponsor stated that it was needed to clarify important "ethical boundaries" in research.

In fiction

For thousands of years, these hybrids have been one of the most common themes in storytelling about animals throughout the world. The lack of a strong divide between humanity and animal nature in multiple traditional and ancient cultures has provided the underlying historical context for the popularity of tales where humans and animals have mingling relationships, such as in which one turns into the other or in which some mixed being goes through a journey. Interspecies friendships within the animal kingdom, as well as between humans and their pets, additionally provides an underlying root for the popularity of such beings.

In various mythologies throughout history, many particularly famous hybrids have existed, including as a part of Egyptian and Indian spirituality. The entities have also been characters in fictional media more recently in history such as in H. G. Wells