Breaking Down the Science Behind Orphan Black
In the BBC America original series Orphan Black, we meet Sarah Manning, a con artist and thief who gets sucked into a conspiracy involving human cloning. During the pilot episode, Sarah witnesses the suicide of a woman who looks identical to her and decides to steal the woman’s identity. As the show progresses, Sarah meets several more clones that share her face, but all have very different personalities.
As someone with roots in Evolutionary Biology, Orphan Black has been a pleasant surprise. While science fiction often exerts poetic license on biology for entertainment value, most of the science discussed in the show is valid or, as with human cloning, has the potential to be true. This is probably due to the efforts of scientific consultant Cosima Herter, a PhD. student in the History of Science, Technology, and Medicine Program at the University of Minnesota (yes, she’s Cosima’s inspiration and namesake).
So what exactly is fact and what is fiction?
Orphan Black focuses on reproductive cloning; the procedure by which a new organism is created that is genetically identical to another. Alternatively, there is therapeutic cloning which doesn’t produce clones, but instead researches human development through the harvesting of stem cells in the hopes of treating diseases, such as Alzheimer’s (Jurmain et al., 2005).
Although many animals have been cloned, Dolly the Sheep made headlines in the mid-90’s for becoming the first mammal successfully cloned from an adult cell (Jurmain et al., 2005).
Dolly was cloned using a process called somatic cell nuclear transfer. A cell nucleus was extracted from an adult sheep cell, it was then inserted into an unfertilized developing egg cell called an oocyte that had its nucleus removed, an electric shock got cell division underway and after a few days the cloned embryo was implanted into the uterus of a host animal, which later gave birth to Dolly (Campbell et al., 1996).
But the fate of Dolly, who was euthanized in 2003 (Giles and Knight, 2003), raises some interesting questions about the biology of cloned organisms, some of which are highlighted in Orphan Black.
Remember Katja, the German clone who kept hacking up blood just before her untimely death? Her poor health suggested that clones could have a weaker immune system and it’s entirely possible. Large Offspring Syndrome is a condition found in cloned animals (mostly lambs and calves), which causes them to have abnormally large organs. This in turn can lead to breathing problems, issues with blood flow and a number of other health problems later in life (Wrenzycki, C., et al., 2004).
No wonder Cosima has been analyzing her own blood.
Could clones have a shorter life span? Maybe. Although Dolly the sheep was euthanized due to a form of lung cancer common in sheep, she also was believed to have aged faster. This could have been caused by shortened telomeres, the DNA sequences that coat the end of a chromosome. Shortening telomeres are a natural part of the ageing process, but it has been implied that since Dolly was cloned from an adult cell, she was born with pre-shortened telomeres, making her genetically older at birth (Shiels et al., 1999).
And then there’s Kira. So far, we’ve learned that two of the clones, Alison and Beth, were unable to have children. Although we’re not entirely sure about the rest, Sarah seems to be the only one with a biological child. So does that make her the original? Not necessarily. Cloned animals haven’t been found to be sterile; in fact, Dolly the Sheep mated and birthed six sheep of her own (Jurmain et al., 2005). So much for that theory then.
One last thing: clones wouldn’t necessarily look identical due to the influence of environment. The first cat to be cloned, a calico named Cc, looks different from its parent because genes do not exclusively determine the color and pattern of coats in cats (Shin et al., 2002).
Likewise, environment plays an important role in human development. Although some of our inherited traits are influenced by alleles at a single genetic location and follow the dominant and recessive expression pattern discovered by Gregor Mendel, there are others traits, such as height, skin color and eye color, that are not as simple. Polygenic inheritance refers to traits influenced by genes located in two or more places. Environmental factors play an important role in the expression of these genes (Jurmain et al., 2005).
So is human cloning actually possible? The truth is yes, sort of. Earlier this month a group of scientists published a paper in Cell reporting successful human cloning, albeit for therapeutic research. No attempts, however, were made to see if the cloned embryos were capable of further development (Tachibana et al., 2013).
But before you start searching train platforms for your doppelgänger, hear me out. The United Kingdom and the European Union have laws prohibiting reproductive human cloning, Canada bans most forms of reproductive cloning and the United Nations has a non-binding ban on all forms of human cloning. There’s currently nofederal law in the United States that completely bans human cloning, although there are thirteen states with reproductive cloning bans in place.
Legal implications aside, yesterday’s science fiction has finally become today’s scientific advancement and Orphan Black definitely capitalizes on the “what if” scenarios that genetics offers. There are also plenty of little nods to science geeks like myself. For example, Dr. Aldous Leekie, whose name is a delicious amalgamation of the Brave New World author and physical anthropology heavyweights Louis and Mary Leakey.
I can’t wait to watch the mystery unfurl even more next season.
Orphan Black airs Saturdays at 9PM EST on BBC America. Season One will be available on Blu-ray and DVD on July 16, 2013 in North America.
Campbell KH, McWhir J , Ritchie WA, Wilmut I. 2004. “Sheep cloned by nuclear transfer from a cultured cell line.” Nature 380,6569: 64–66.
Giles J and Knight J. 2003. “Dolly’s Death Leaves Researchers Woolly on Clone Ageing Issue.” Nature 421:776
Jurmain R, Kilgore L and Trevathan W. 2005. Introduction to Physical Anthropology: Tenth Edition. Australia: Thomson Wadsworth.
Shiels PG, Kind AJ, Campbell KH, et al. 1999. “Analysis of telomere length in Dolly, a sheep derived by nuclear transfer”. Cloning 1,2: 119–25.
Shin T, et al. 2002. “Cell biology: a cat cloned by nuclear transplantation.” Nature415,874: 859-859.
Tachibana et al. 2013. “Human Embryonic Stem Cells Derived by Somatic Cell Nuclear Transfer.” Cell 153,5: 1-11.
Wrenzycki, C., et al. 2004. “Gene expression patterns in in vitro-produced and somatic nuclear transfer-derived preimplantation bovine embryos: relationship to the large offspring syndrome?” Animal reproduction science 82: 593-603.