question: Why cannot there ever be a successful breeding between a human being and another animal?
comment: Huge over simplification; when you make a baby, its DNA comes equally from the mom and the dad. The DNA is a big set of building instructions, and a playbook of how to react to situations. For humans, we get every odd page from Mom, and even pages from Dad. Most of the time, the instructions still make sense. Chimeras, like mules, ligers, and tilons have building instructions close enough that it doesn't die instantly. Imagine trying to assemble an F35, if the guide book has the instructions for an F16 in English in the evens, and an s300 in Swahili on the odd pages. You might get somewhere, but will it fly?
passages: Hybridization between members of different but related genera is sometimes possible, as in the case of cama, wholphin, and some felid hybrids, for example.
  
  Section::::Reports of attempted hybridization.
  
  There have been no scientifically verified specimens of a human–chimp hybrid, but there have been substantiated reports of unsuccessful attempts at human/chimpanzee hybridization in the Soviet Union in the 1920s, and various unsubstantiated reports on similar attempts during the second half of the 20th century.
  
  Ilya Ivanovich Ivanov was the first person to attempt to create a human–chimp hybrid by artificial insemination.
   Advances in genetic engineering have generally caused a large amount of debates and discussion in the fields related to bioethics, and research relating to the hypothetical creation of human-animal hybrids in the future has been no exception. The technical analyses of intermingling human-based and animal-based genetic material are ongoing; the ethical, moral, and legal issues arising from actual research using chimeras (rather than hybrids per se) at the moment also touch more speculative concerns as well. 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. 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.
   Section::::New technologies.:Interspecific pregnancy.
  
  A potential technique for aiding in reproduction of endangered species is interspecific pregnancy, implanting embryos of an endangered species into the womb of a female of a related species, carrying it to term. It has been used for the Spanish Ibex and Houbara bustard.
  
  Section::::Ethical Considerations.
   BULLET::::- Robert Armitage Sterndale mentioned experimental golden jackal/dog hybrids from British India in his "Natural History of Mammals in India and Ceylon", noting that glaring jackal traits could be exhibited in hybrids even after three generations of crossing them with dogs
   Several years ago, I saw confined in the Zoological Gardens of London a female hybrid from an English dog and jackal, which even in this the first generation was so sterile that, as I was assured by her keeper, she did not fully exhibit her proper periods; but this case, from numerous instances have occurred of fertile hybrids from these two animals, was certainly exceptional.
   BULLET::::- Second, not all hybrids exhibit heterosis (see outbreeding depression).
  
  An example of the ambiguous value judgements imposed on hybrids and hybrid vigor is the mule. While mules are almost always infertile, they are valued for a combination of hardiness and temperament that is different from either of their horse or donkey parents. While these qualities may make them "superior" for particular uses by humans, the infertility issue implies that these animals would most likely become extinct without the intervention of humans through animal husbandry, making them "inferior" in terms of natural selection.
  
  Section::::Genetic and epigenetic bases.
   Animals of domestic origin sometimes can produce fertile hybrids with native, wild animals which leads to genetic pollution (not a clear term itself) in the naturally evolved wild gene pools, many times threatening rare species with extinction. Cases include the mallard duck, wild boar, the rock dove or pigeon, the red junglefowl ("Gallus gallus") (ancestor of all chickens), carp, and more recently salmon. Other examples of genetic swamping lie in the breeding history of dingoes. Dingoes are wild true dogs that will interbreed with dogs of other origins, thus leading to the proliferation of dingo hybrids and the possibility of the extinction of pure wild dingoes. Researches in Scotland have remarked on a similar phenomenon of the genetic mixing of feral domestic cats and their wild counterparts.
   Section::::Disadvantages of DHs.
  
  The main disadvantage with the DH population is that selection cannot be imposed on the population. But in conventional breeding selection can be practised for several generations: thereby desirable characters can be improved in the population.
   BULLET::::- At Chester Zoo in the United Kingdom, a cross between an African elephant (male) and an Asian elephant (female). The male calf was named Motty. It died of intestinal infection after twelve days.
  
  BULLET::::- Cagebird breeders sometimes breed hybrids between species of finch, such as goldfinch x canary. These birds are known as mules.
  
  BULLET::::- Gamebird hybrids, hybrids between gamebirds and domestic fowl, including chickens, guineafowl and peafowl, interfamilial hybrids.
  
  BULLET::::- Numerous macaw hybrids are also known.
   In the 1980s, there were reports on an experiment in human–chimpanzee crossbreeding conducted in the People's Republic of China in 1967, and on the planned resumption of such experiments.
  
  In 1981, Ji Yongxiang, head of a hospital in Shengyang, was reported as claiming to have been part of a 1967 experiment in Shengyang in which a chimpanzee female had been impregnated with human sperm. According to this account, the experiment came to nothing because it was cut short by the Cultural Revolution, with the responsible scientists sent off to farm labour and the three-months pregnant chimpanzee dying from neglect.
   BULLET::::- Sheep: Marked the first mammal being cloned (1984) from early embryonic cells by Steen Willadsen. Megan and Morag cloned from differentiated embryonic cells in June 1995 and Dolly the sheep from a somatic cell in 1996.
  
  BULLET::::- Rhesus monkey: Tetra (January 2000) from embryo splitting and not nuclear transfer. More akin to artificial formation of twins.
  
  BULLET::::- Pig: the first cloned pigs (March 2000). By 2014, BGI in China was producing 500 cloned pigs a year to test new medicines.
  
  BULLET::::- Gaur: (2001) was the first endangered species cloned.
  
  BULLET::::- Cattle: Alpha and Beta (males, 2001) and (2005) Brazil
   Since Gateway cloning uses patented recombination sequences, and proprietary enzyme mixes available only from Invitrogen, the technology does not allow researchers to switch vendors and contributes to the lock-in effect of all such patented procedures.
  
  To summarize the different steps involved in Gateway cloning:
  
  BULLET::::- Gateway BP reaction: PCR-product with flanking att B sites (this step can also use other methods of DNA isolation, such as restriction-digestion) + Donor vector containing att P sites + BP clonase = Gateway Entry clone, containing att L sites, flanking gene of interest
   Cases of accidental breeding of wolfdogs are known (though this is very rare), where a domestic dog female in oestrus strays and is mated by a male wild wolf.
   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.
   Breeding programs are commonly employed in several fields where humans wish to change the characteristics of their animals' offspring through careful selection of breeding partners:
  
  BULLET::::- Dog and cat fanciers may coordinate a breeding program to raise the probability of an animal's litter producing a championship-caliber animal.
  
  BULLET::::- Horse breeders try to produce fast racehorses through breeding programs.
  
  BULLET::::- Conservationists use breeding programs to try to help the recovery of endangered species by preserving the existing gene pool and preventing inbreeding.
   BULLET::::- HLA genes are highly polymorphic between individuals. Any two individuals with similar HLA genes could be possibly related. Mating of two related individuals would result in inbreeding which can be harmful to the offspring since it would result in a greater amount of genetic homozygosity thus increasing the chances of recessive mutations.
  
  Section::::Criticism.
   Section::::Birth and career.
  
  J. P. Willey of Salmon Falls, New Hampshire, was already a cocker spaniel breeder in America when he attempted to purchase Obo from Farrow in England. He was turned down, but managed to purchase Chloe II, a successful female Cocker Spaniel show dog and had her mated to Obo prior to her being shipped to the United States.
  
  From Chloe II's litter came two males, Obo and Black Silk, and a female named Black Gem. Black Gem would die from distemper after returning from winning the Produce Stake at a New York show.
   The observable phenomenon of hybrid vigor stands in contrast to the notion of breed purity. However, on the other hand, indiscriminate breeding of crossbred or hybrid animals may also result in degradation of quality. Studies in evolutionary physiology, behavioral genetics, and other areas of organismal biology have also made use of deliberate selective breeding, though longer generation times and greater difficulty in breeding can make such projects challenging in vertebrates.
  
  Section::::Plant breeding.
   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 inherently "not the kind of thing we support" in his kind of research since scientists should "want to respect human life". "There are chimeras out there that serve very valuable purposes in medical research, such as mice that make human antibodies," Michael Werner, the chief of policy for the Biotechnology Industry Organization, has commented.
   The team at the Roslin Institute were seeking a way to modify the genetic constitution of sheep and cattle more effectively than the hit and miss method that was the only method and had sort of aids available at the time – microinjection. In microinjection, DNA is injected into the pronucleii of fertilized oocytes. However, only a small proportion of the animals will integrate the injected DNA into their genome and in the rare cases that they do integrate this new genetic information, the pattern of expression of the injected piece of DNA's gene, due to the random integration, is very variable.
   University of Wisconsin–Madison bioethicist Alta Charo said that even in other ape-like mammals, the risk for miscarriage, birth defects, and life problems remains high. Arthur Caplan, the director of the Center for Bioethics at the University of Pennsylvania, expressed concerns that many dead and sick children could result from the cloning of human beings.
  
  Section::::Alleged clone baby Eve.:Request for a temporary guardian.
   Section::::New technologies.:Cloning.
   In 2018 Chinese research scientists produced 29 viable mice offspring from two mother mice by creating sperm-like structures from haploid Embryonic stem cells using gene editing to alter imprinted regions of DNA. They were unable to get viable offspring from two fathers. Experts noted that there was little chance of these techniques being applied to humans in the near future.
  
  Section::::Ethics.
   BULLET::::- A cloned baby mouflon was born to a domestic sheep in a successful interspecies cloning of an endangered species in Iran in 2015.
  
  Section::::Mule.
  
  BULLET::::- Idaho Gem (male, 2003) was ranked third in the world among racing mules.
  
  BULLET::::- Utah Pioneer (male, 2003)
  
  BULLET::::- Idaho Star (male, 2003)
  
  Section::::Pig.
  
  BULLET::::- 5 Scottish PPL piglets (Jose, Josúe, Juan, Amber and Jose) (2000)
  
  BULLET::::- Xena (female, Meishan pig, 2000-2010)
  
  BULLET::::- BGI, China was reported in 2014 to be producing 500 cloned pigs a year, with a success rate of 70-80%, to test new medicines.
  
  Section::::Pyrenean ibex.
   Human impact on the environment has resulted in an increase in the interbreeding between regional species, and the proliferation of introduced species worldwide has also resulted in an increase in hybridisation. This genetic mixing may threaten many species with extinction, while genetic erosion in crop plants may be damaging the gene pools of many species for future breeding. A form of often intentional human-mediated hybridisation is the crossing of wild and domesticated species. This is common in both traditional horticulture and modern agriculture; many commercially useful fruits, flowers, garden herbs, and trees have been produced by hybridisation. One such flower, "Oenothera lamarckiana", was central to early genetics research into mutationism and polyploidy. It is also more occasionally done in the livestock and pet trades; some well-known wild × domestic hybrids are beefalo and wolfdogs. Human selective breeding of domesticated animals and plants has resulted is the development of distinct breeds (usually called cultivars in reference to plants); crossbreeds between them (without any wild stock) are sometimes also imprecisely referred to as "hybrids".
  