Cloned primates are here! Over three decades have passed since the birth of Dolly, the sheep, scientists have now tackled cloning mammals that are even closer to us on the evolutionary tree: macaque monkeys. What does this mean for a society that witnesses dramatic changes day by day: computers are outperforming doctors in calling out heart abnormalities in patients; 3D-printed organs are bringing us one step closer to tissue restoration; genome sequencing has become an online product easily available for anyone curious about their ancestry, bodybuilding, or just simply wine tastes. Breakthroughs in science and technologies are so prevalent in our life that by now, we probably shouldn’t be surprised by any new discovery. Yet when the two cute, little, cloned monkeys were born, the whole world was, once again, shaken.
Published in Cell on January 24th, 2018, a study from a group of scientists in China reported their methods in generating two non-human primates that are genetically identical. To clone the two identical macaque monkeys, the scientists applied Somatic Cell Nuclear Transfer, the same method that generated Dolly in 1996. The key idea behind cloning is that a new organism, be it sheep or monkey, is generated without sexual reproduction. Asexual reproduction is not as uncommon as one would think, plenty of plants do so. For example, Bryophyllum shed plantlets from the edge of the leaves to produce new plants. Some insects, such as ants and bees, also exploit asexual reproduction to clone a huge working class army. Since asexual reproduction is essentially an organism duplicating itself, the offsprings are all genetically identical. Evolution, however, doesn’t favor asexual reproduction as identical offsprings don’t prevail in a fast changing environment. On the other hand, sexual reproduction combines different sperms and eggs to create diverse offsprings, of which some may survive. To combat challenges from the mother nature, higher organisms, such as mammals, almost exclusively reproduce sexually. This is why a cloned monkey, an anti-evolution human creation, is mind blowing.
To clone mammals, scientists came up with the idea of transferring the nucleus of a somatic cell to an enucleated egg (an egg that lacks nucleus). Unlike germ cells (sperm and eggs), somatic cells refer to any cells that don’t get passed onto the next generation. These cells have the full genome of an organism that is split equally in germ cells during sexual reproduction. Carrying half of the genome, sperm and egg need to fuse their genetic materials to make one viable embryo. Technically, the nucleus of a somatic cell holds all the genetic information an organism needs. Thus, by inserting the somatic cell nucleus into an egg, scientists could generate a functional embryo. But why not into a sperm? Evolution has trimmed mammalian sperm tremendously so that it can accomplish its only job better: swim faster to fertilize the egg. As a result, not much other than the sperm’s genetic information is incorporated into the fertilized egg and the embryo relies on the cellular machinery from the egg to finish development. Using this technology, the scientists generated over 300 “fertilized” embryos. Of these embryos, 260 were transferred to 63 surrogate mothers to finish developing. 28 surrogate mothers became pregnant, and from those pregnancies, only 2 healthy monkey babies were born. Although they were carried by different surrogate mothers, every single piece of their genetic code is the same as the the somatic nucleus provider, a real-life demonstration of primate-cloning. Followed by millions of people since their debut to the world, these two macaque superstars are the living samples of a revolutionary breakthrough in our science and technologies.
Despite the extremely low success rate, this technology erects another monument in the history of mankind’s creations. Carrying identical genetic information, cloned monkeys like these two can be a very powerful tool in biomedical research and diseases studies. Co-author Mu-ming Poo, director of the Chinese Academy of Sciences’ Institute of Neuroscience in Shanghai, said that these monkeys could be used to study complicated genetic diseases where environmental factors also play a significant role, such as Alzheimer’s and Parkinson’s diseases. While there are ethical concerns on this technology and its easy application to human cloning, it is worth noting that almost all human creations (explosives, GMO food, the internet, etc.) are double-sided swords. It is up to the hand that wields this sword to decide whether to do good or bad. It is wise to be cautious with the development of new technologies, but it’s also important not to constrain our creativity. After all, it is our creative minds that drive us toward creating a better life for everyone.
Peer edited by Cherise Glodowski.
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