A new ethical dilemma: why do scientists have created the embryo of the "Chimera" of human DNA and the pigs?

The world came near to one of the ethical dilemmas, which we didn't want to think. The scientists produced embryos, combining DNA from pigs and humans to make the so-called Chimera. They were developed over several weeks before it was destroyed. It's safe to assume that the embryos-hybrids will soon evolve further, but technical problems made their development more complex than scientists expected.

http://fb.ru/post/science/2017/1/30/9716#image84004
How are chimeras Chimeras are organisms formed from two fertilized cell, or zygote, taken from various types. Judging by the title, they should stay on the pages of the books of JK Rowling or ancient mythology, but there are good reasons why some scientists want to create them. In particular, people are dying from lack of donor organs such as the heart and kidneys. The Chimera created by combining the fertilized cells of pigs and humans may be the solution to this problem, as they will be the source of quite similar to our own bodies, which could be effectively transplanted.
Ethical issues, Many believe that this idea even sounds terrifying, but others claim that it is no worse than farming animals, often in appalling conditions, simply in order to eat them. In addition, it would be difficult to explain to someone whose only hope for survival is a liver of the Chimera, this idea seems too repulsive for implementation. Science fiction writers and philosophers for some time tried to solve this ethical problem, but political institutions and the General public, as a rule, laid it in the basket complicated things that we don't have to worry. - Read more at
http://fb.ru/post/science/2017/1/30/9716#image84006
Therefore, the statement about the successful establishment of the embryo-hybrid serves as a Wake-up call that we can no longer postpone the solution of this problem and should deal with it now.
The initial stage of the scientists ' work Efforts lead researcher Professor Juan Carlos Belmonte from the Salk Institute and his team showed that in this matter, there are not only ethical obstacles. "The ultimate goal is to grow functional and portable tissues and organs, but we are far from that, said Belmonte in a statement. — This is an important first step."
http://fb.ru/post/science/2017/1/30/9716#image84007
Belmonte started with placed the stem cells of the rat in the mouse embryo. This was done previously by other researchers. He then used tools to edit genes in order to remove the genes responsible for the development of specific organs in mice, and replaced them with rat equivalents. "Rat cells have a functional copy of the missing gene of the mouse, so that they can displace the mouse cells and occupy freed niches for the development of organs," said the first author of this study Dr. Jung Woo, also from the Salk Institute.
http://fb.ru/post/science/2017/1/30/9716#image84002
Why are the pigs Briony Human stem cells previously was injected into mouse embryos, but the results were insignificant. Belmont and Woo went ahead and tried to enter cells of human embryos, cows and pigs. Part of the work with the embryos of the cows proved to be more difficult and costly, therefore the choice was made in favor of the pigs.
http://fb.ru/post/science/2017/1/30/9716#image84001
But even after that the work was not easy. From the moment of conception to the birth of pigs is less than four months, so their development is much faster than humans. Despite the fact that the team managed to get interim human pluripotent stem cells to form chimeras within a fetal pig, a hybrid more like an animal, not human. The authors think this is a good result, as many of the biggest ethical problems arise in the case of a creature with a human brain.
http://fb.ru/post/science/2017/1/30/9716#image84000
The embryos were destroyed after 3-4 weeks, and they showed their viability at this stage. The authors are working on the installation of specific human genes in the subsequent chimeras (as was done when working with rats and mice) to create more human bodies.