Value of Reproductive Cloning

Since the cloning of a sheep named Dolly in the 1990s, cloning has been a hot button issue.  Cloning is the growing of a new living thing; cell, tissue, organ, or entire plant or animal, in a manner that its DNA is identical to a currently, or previously existing one (Cloning Fact Sheet).  Meiosis is the type of cell division specific to sexual reproduction, so any form of reproduction that lacks meiosis is asexual and thus is a form of natural cloning (Asexual Reproduction).  Asexual reproduction is a natural form of reproductive cloning by which a cell or organism creates a replica of itself and then divides in two.  Cells within the human body normally reproduce in this way.  Many plants reproduce by cloning as well.  Any plant that produces seeds that don't need to be fertilized by another plant to propagate is virtually cloning itself (Asexual Reproduction).  We can induce this type of propagation as well sometimes, by separating parts of a plant and growing new plants from them.  One relatable example is the potato.  Once the tuber develops sprouts (commonly called eyes) it can be broken up, and each portion will grow a different plant with identical DNA.  This type of reproductive cloning is used in agriculture.  Typically though, when people think of reproductive cloning, they thing of the laboratory process of joining an adult cell with an egg to form a zygote that is then implanted into a surrogate to mature naturally until birth. (Genome)

Does reproductive cloning artificially narrow, or expand the gene pool?  By adopting the use of cloning for reproductive purposes the variations in DNA that would normally happen through reproduction are eliminated.  However, if used properly, the opposite could be done.  If there is a low population of an endangered animal, taking cell samples from healthy adults to use for a breeding program could help to keep up genetic diversity instead of the opposite happening naturally.  It could also be used to introduce new DNA into an isolated population to help widen their genetic diversity.  Although a clone is considered to be genetically identical to the donor, mitochondrial DNA supplied by the egg after the nucleolus has been removed, does play a role as well.  The prospect of what this could do to expand genetic diversity in dwindling populations is exciting for conservationists (Barchfield).

Is reproductive cloning  very successful?  Dolly the sheep's success was an amazing feat, because many in the scientific community didn't believe that differentiated adult cells could be reprogrammed to grow a new animal.  Although this has been shown to be possible, often times cloning attempts fail, or result in abnormal, or deformed clones.  It is thought that some of this may be due to issues in the reprogramming of the differentiated cells.  It might be possible for the process to be more successful with the use of somatic stem cells (commonly called adult stem cells) instead, since they remain undifferentiated (Stem Cell Basics).  So far of the over eighteen (About Reproductive Cloning) animals cloned most have had health challenges and have died younger than a normal expected lifespan for their species.  This leads many to question how effective cloning really is, and if cloning is ethical because of the effects it has on the life of the clone.  

How would human reproductive cloning be applied?  There are several ways that reproductive cloning can be used.  As mentioned earlier, it is already used in agriculture, and there is hope of using it in conservation efforts, but what about human applications?  There have been scientists who have shown an interest in cloning both modern humans, and human ancestors.  Some scientists have proposed cloning an Neanderthal to be able to better understand our genetic past (Swanson).  Although there are many differing views on human cloning, it hasn't happened yet.  Many believe that it will come to pass in the next few years, despite the controversy.  Another possible application of reproductive cloning is to allow people who can't otherwise have a child to have genetic offspring.

There are some great ideas that people have come up with for the application of reproductive cloning, but there are many ethical questions about whether or not human cloning should go forward.  Several countries have banned human cloning preemptively, and although the United States is not one of them, it is expected that the first human clone will be produced outside of the US, and that the process will be privately funded.  Although those who oppose cloning cite not only ethical issues, but the high risk of deformity to clones, proponents say that cloning is constantly improving and that there are similar risks associated with traditional sexual reproduction as well (Scientific and Medical).  

Although I am not completely opposed to cloning, I am split on the reproductive cloning issue.  I believe there are some benefits offered by cloning in an agricultural setting, and that the opportunity to try and protect endangered animals is something that should certainly be considered.  I don't think that cloning humans or distant, extinct members of any species is advisable.  Human cloning could result in health complications for the clone physically, but may also pose huge psychological difficulties for them as well.  Clones look exactly like their donors, so that haunting feeling that you're looking just like your mother as you age, would be even more real for a clone.

Reproductive cloning is much broader of a topic than many people realize and includes not only animal cloning, but also plant cloning and natural cloning that transpires on a cellular level.  There are both benefits and risks to cloning and many find that there are ethical issues that we face when considering cloning animals and humans in particular.  It is important to understand reproductive cloning and all that is included in that field to be able to make informed decisions about whether or not you believe it is ethical and so that when it becomes a policy issue you can make the best choice possible.

And for some levity I've included this fun spoof song about cloning by Al Yankovic.




Sources:

Barchfield, Jenny. With Animals Under Threat, Brazilian Team Aims to Clone 8 Wild Species. 15 November 2012. The Washington Post. http://www.geneticsandsociety.org/article.php?id=6517. Accessed 3 March, 2013.

Swanson, Emily. Neanderthal ClonePoll Finds Most Americans Oppose Cloning Human Relative. 30, January 2013. Huffington Post. http://www.geneticsandsociety.org/article.php?id=6664 . Accessed 3 March, 2013.

About Reproductive Cloning. Center for Genetics and Society. http://www.geneticsandsociety.org/section.php?id=16 . Accessed 2 March 2013.

Asexual Reproduction. UCMP Berkeley. http://www.ucmp.berkeley.edu/glossary/gloss6/asexual.html. Accessed 2 March 2013.

Cloning Fact Sheet. Human Genome Project Information. http://www.ornl.gov/sci/techresources/Human_Genome/elsi/cloning.shtml . Accessed 2 March 2012.

Reproductive Cloning Process Diagram. Genome.gov. http://www.genome.gov/pages/education/illustration_of_cloning.htm . Accessed 2 March 2013.

Scientific and Medical Aspects of Human Reproductive Cloning (p 76). The National Academies Press. http://www.nap.edu/openbook.php?record_id=10285&page=76. Accessed 3 March 2013.

Stem Cell Basics. National Institute of Health. http://stemcells.nih.gov/info/basics/pages/basics4.aspx. Accessed 3 March 2013.