If we’re talking about a cross between a human and a Holstein cow-well, that’s not going to happen.

But in fact, animal-human hybrid work has been going on for a number of years in labs all over the world.  Thousands of animals contain human cells or DNA. Most of these are mice with a single gene sequence of human origin.

There are mice with human-like livers that allow scientists to study the effects of drugs. Some lab monkeys carry a human form of the Huntington’s disease gene that permits scientists to investigate the development of the disease. There are sheep and pigs with bits of human organs growing inside them.  The goal is that these animals will grow organs that can be used by humans.

Pig heart valves have been implanted in humans for some years now. There is hope that pig cells can be used for diabetes treatment. Fetal pig neurons have been implanted into the brains of people with Parkinson’s disease. Pig liver cells have been used experimentally to cleanse the blood of people with liver failure, hoping to keep them alive until a donor can be found.

Stem cells have been created by inserting human genomes into rabbit eggs. Researchers have made mice with human prostate glands. Several sheep now live with a half-human liver.

DNA from humans is inserted into bacteria to recreate the insulin gene and the insulin is used for many diabetic patients nationwide.

The goal of all this “recombinant DNA technology” research is to save lives and to study drugs and diseases. You can’t use people in gruesome but necessary experiments. In stem cell research, the human cells are the therapy, and under federal (FDA) rules you have to test them in animals before you test them in people.

Some recent research has been truly exciting.  They are doing to brain cells what they have previously done with liver and kidney cells. There are now humanized mice with Alzheimer’s symptoms. Neurological disorders kill 7 million people every year.

What has been described above is not the same as whole body cloning. Cloning is the process of creating an identical copy of an organism. Dolly, the sheep, was cloned in Scotland in 1996. She lived for six years. A cell was taken from her biological mother, transferred into the egg of a female sheep, implanted into the surrogate mother, grew into a fetus, and eventually into an identical baby copy of the original animal.

Dolly was controversial and cloning is not simple. The success rate is terrible. Dolly was born after 277 eggs were used to create 29 embryos, which produced 3 lambs and only one lived.

There is talk about bringing back extinct species by cloning dead specimens and growing them in the wombs of similar animals. The Wooly Mammoth has been extinct since 1700 B.C. and the DNA of these creatures has been preserved fairly intact in the frozen ice of the Russian tundra. This DNA transfer and cloning have raised serious moral and ethical issues. Should we be tampering with Mother Nature? What are the risks and benefits? Is our science ahead of our rules and regulations in this area?

Sources: http://www.livescience.com and  www.ornl.gov/sci/techresources