More recently, it was believed that individuals of different biological species should not be crossed. However, a number of facts and scientific experiments indicate that this statement is controversial, at least for mammals.
So, an incredible story happened in the Chinese province of Jiangxi. A dog belonging to a peasant named Zeng gave birth to three cubs, one of which was a regular puppy, and the other two were … kittens!
In fact, people have been trying to cross different breeds of animals for a long time. So, a well-known hybrid of a horse and a donkey is a mule. Mules are distinguished by their endurance, and they were used to transport luggage over long distances in the Middle Ages.
There are also hybrids of a tiger and a lion (ligers and tigers), a lion and a leopard (leopard), a dog and a wolf (dog wolf), a zebra and a horse, a donkey or a pony (zebroids), a camel and a llama (camellama), a grizzly bear and a polar bear (polar grizzly), black killer whale and dolphin (killer whale dolphins). People have even managed to breed hybrids of hybrids - for example, a cross between a tiger and a liger or a tiger lion. And biologists from the French Institute of Agronomic Research (INRA) succeeded in implanting an artificially fertilized egg of a Japanese sika deer into a female European red deer.
Thus, scientists believe, it will be possible to preserve rare and endangered species of animals. True, the fetus will take root only if the surrogate mother and the “adopted” cub are of a close breed. In the near future, the researchers intend to begin recreating the population of the Mesopotamian fallow deer and Elda deer inhabiting Iran and Iraq.
However, as a rule, such animals do not give offspring in natural conditions, and human intervention is necessary for their breeding.
The scientific world regularly discusses the ethical aspects of experiments to create chimeras - mutants in whose body genes from humans and animals are present.
For example, researchers from the Stanford University Stem Cell Institute conducted experiments on growing embryos of mice, into whose brains were injected with human neurons. True, the mutant was not allowed to grow up to the end: the fetus was destroyed just before birth, and then they opened it to study the brain structure of the chimera.
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In addition, an experiment is being prepared to grow a human body from genetically modified mouse cells. Genetic modification will allow the reproductive organs of rodents to produce human sperm and eggs, from which a human embryo will subsequently be grown.
According to the Cell Research magazine, Chinese scientists from the Second Shanghai Medical University managed to obtain a hybrid … of a human and a rabbit! As experimental material, we used skin cells of two men, one woman and two boys, and the eggs of a rabbit. Researchers removed DNA from rabbit eggs and injected human DNA into them.
Of the 400 embryos obtained, only 100 survived. However, at a certain stage of development, all embryos were destroyed.
Previously, similar experiments have already been conducted in Massachusetts (USA), where scientists tried to cross the genes of humans and cows. But they ended in vain.
And Sydney researchers injected human bone marrow cells into a lamb fetus. Over time, they developed into completely human bones and muscles. The next step was to create a hybrid … a man and a pig! For this purpose, the nucleus of a human cell was implanted into the nucleus of a porcine ovum, the code of which had previously been changed by removing the animal's genes. The embryo lived for 32 days, until the creators themselves decided to destroy it …
Indian scientists from the Center for Cellular and Molecular Biology of Hyderabad succeeded in realizing the idea behind the famous film The Fly. Only in the film did the fly's genes get into the human body, but here, on the contrary, a human gene was introduced to an ordinary fruit fly. On it they gathered to test new drugs for cancer … The Chinese have grown a human auricle … on the back of a mouse! Hence, individual human organs can be grown for transplantation. The main thing here is to prevent the genes of the "incubator" animal from entering the cells …
But what about the "canine-cat" phenomenon? Maybe there was also an artificial crossing? It is possible that some eminent scientist or a whole disguised scientific laboratory experimented on Zeng's dog. But why are they keeping their discovery a secret?
Margarita Troitsyna