Written by Cameron DeWith
This week’s title is the name of a classic Al Yankovic parody; I thought it would be extremely fitting for a blog post about cloning. I decided upon my topic this week based on the prompt: “Pick a favorite science fiction technology and research how close we are to achieving it.” Cloning is prominent in many science fiction movies and television shows, but it is more than just a topic of the imagination. It is a topic of reality!
How Cloning Works
Real cloning does not occur in the same way as it does in movies. Unlike in the movies, clones do not grow in artificial wombs. Nor are they exact duplicates with the memories of the creature whose DNA they share. So, how does cloning actually work? Well, there are three types of cloning that I will briefly explain.
Gene cloning produces copies of genes or sections of DNA. A specific gene from one organism is added to the DNA of a vector. A vector could be bacteria, yeast, or viruses. The vector then reproduces into colonies to mass-produce the gene. The millions of resulting gene clones are extracted from the bacteria and modified. Gene modification occurs when genetic engineers remove sections of DNA and replace them. These modified genes are then transferred into an organism. The genetic changes made to the organism pass onto future descendants.
Reproductive cloning requires the removal of a somatic cell from one organism. Somatic cells include all cells besides sperms or eggs. The DNA from the somatic cell is then transferred into an egg cell which has had its nucleus removed. This transfer is possible through two methods. In the first method, a needle removes the nucleus from the somatic cell and places it into the egg. In the second method, an electric current fuses the whole somatic cell with the egg. Finally, in both methods, the egg develops into an embryo in a test tube before it goes into the uterus of a female the same species as the egg. The female then gives birth to an organism that has the same genetic make-up as its somatic cell donor.
Therapeutic cloning occurs in much the same way as reproductive cloning. However, instead of producing an organism, genetic engineers use the cloned embryo to create stem cells with the same DNA as the cell donor. These stem cells can then replace patients’ damaged cells. Because genetic engineers gather stem cells from cloned embryonic cells early in embryonic development, the embryo dies before its exit from the test tube.
Dolly the Sheep
Cloning has developed through a series of scientific discoveries dating all the way back to 1885. In the interest of time, I will only go through the breakthrough I feel is the most important: the cloning of Dolly the sheep.
In 1996, Ian Wilmut and Keith Campbell created Dolly, the first mammal cloned using somatic cell nuclear transfer. The nucleus from an adult sheep’s udder was transferred into an empty egg. This new cell developed into an embryo that was placed in a female sheep’s uterus to complete development. But what made this accomplishment so hard to achieve? Every cell contains a full set of DNA, but adult cells decommission genes that they do not need in carrying out their specific functions. In order to clone a creature from an adult cell, the cell’s DNA must revert back to its embryonic form. This is a very difficult process that is only effective some of the time. For instance, it took 277 tries to finally create Dolly.
Future Cloning Uses
Reproductive cloning could be important for the saving of endangered species, or even for the resurrection of species long extinct.
In an article, “The future of cloning”, published in the scientific journal Nature, Gurdon and Colman stated their belief that “the greatest eventual benefit of … [cloning] will be in therapeutic cloning” (4). In therapeutic cloning, a patient’s cell is placed in a donated egg and induced to begin developing embryonic cells that divide to produce stem cells with a patient’s own DNA. Because stem cells develop into numerous cells and tissues, they can replace a patient’s damaged cells or tissue. Because the cells or tissue have the same DNA as the patient, they would not be rejected by the body.
There are many ethical issues surrounding cloning, many of which came to light in the public eye after the cloning of Dolly.
Some believe that saving endangered species or bringing back extinct species using cloning does not accomplish anything because these clones, who are genetically identical to their predecessors, will surely die if the conditions which caused their endangerment or extinction remain the same.
Many people believe that therapeutic cloning is morally impermissible because it requires the creation of a human embryo for the sole purpose of harvesting its stem cells. This embryo, if put into a woman’s uterus, could have become a human being. It can be argued that therapeutic cloning is equivalent to killing a human being in order to harvest their organs.
Human reproductive cloning is unethical. Most clones die before birth, and many of those that survive have life-altering irregularities because of problems with reprogramming an adult cell back to its embryonic form. Clones also commonly have irregular birth weights which are either higher or lower than normal. Finally, atypical placentas or overly large fetuses can put the surrogate mother at significant risk.
Stem cell research requires thousands of eggs. Because each woman typically produces only one or two developed eggs per cycle, many women would need to take stimulatory drugs to increase the supply of eggs for research. Liver damage, kidney failure, and strokes are all potential byproducts of the drug in rare cases. Whether it is ethical to have women take this drug is hotly debated. Furthermore, the extraction of eggs is intrusive and poses some risks to women. As well, many argue that women should be paid for their donated eggs, but current guidelines in countless countries prohibit paying women for their eggs beyond expenses arising out of the procedure.
Real-world cloning might not be like it is in the movies, but it plays an important role in science. Cloning has many potential applications, but there are also many ethical issues surrounding reproductive and therapeutic cloning. Personally, I think that we need to be very careful in our implementation of cloning because many controversies surround the practice. In addition, standardized regulation has yet to be created because of the relative newness of cloning and the research which still needs to be done before it is widely used. When we make this standardized regulation, we will need to listen to all of the opinions and evidence which exist in order to come up with practices that are both morally permissible and beneficial to humanity.