The practice of genetic engineering in humans has been explored in numerous science fiction stories, such as Andrew Niccol’s Gattaca and Aldous Huxley’s Brave New World. In some stories manipulation of genes opens a door to a wild, dystopic future, such as the universe encountered in Samuel R. Delany’s Einstein Intersection. On the other hand, some speculative futures, such as Olaf Stapledon’s Last and First Men, paint a picture where genetic engineering is a bridge to disease control, self-evolution, and more.
I’m not referencing awesome science fiction novels just because I’m a huge sci-fi geek. The term “genetic engineering” happens to be rooted in science fiction. “Genetic engineering” was first coined in Jack Williamson’s science fiction book Dragon’s Island, which was published in 1952, one year before DNA’s role in hereditary was proven.
Incredibly, it only took science two decades to perform what Williamson had only written in words. In 1973 Herbert Boyer and Stanley Cohen inserted antibiotic resistance genes into an E.coli bacterium, marking the creation of the first genetically modified organism. In 1974, scientists created the first genetically modified animal by injecting viral DNA into mice.
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Genetic engineering has come a long way since the groovy 70’s. In 2010, scientists at the J. Craig Venter Institute created Synthia, the first synthetic life form. They accomplished this incredible feat by inserting a synthetic bacterial genome into a cell containing no DNA.
The creation of synthetic life is remarkable, but let’s get back to the natural, more complex, and messier kingdom of animals. Last week researchers from China reported the successful creation of genetically modified monkeys using a relatively new and direct method of genome editing involving the use of CRISPRs, a type of nuclease found in many bacteria. The monkeys in the experiment were originally macaques, marking the first time targeted genome editing (direct genetic engineering) has been used in primates. This could potentially pave the way for quick and easy genetic engineering in humans.
Scientists have genetically engineered monkeys in the past, but never before have they been able to directly add, remove, or alter a target gene site. A past example of genetic engineering in a primate that you may remember is when scientists injected jellyfish DNA into a rhesus monkey in 2001. The difference between 2001 and 2014 is that thirteen years ago scientists were practically shooting blind. Using different synthetic nuclease like CRISPR, scientists have unparalleled control over the genes they choose to alter, and in what ways they are able to alter them. As the Chinese researchers explain,
the application of monkeys in biomedical researches has been significantly hindered by the difficulties in producing animals genetically modified at the desired target sites. Here, we first applied the CRISPR/Cas9 system, a versatile tool for editing the genes of different organisms, to target monkey genomes.
Three specific genes in the monkeys were modified by the researchers: one that regulates immune cell development, another that regulates metabolism, and a third that regulates sex determination as well as stem cells. Interestingly, the monkeys were altered in various ways depending on how far along the monkey embryo had developed. According to Wezhi Ji, a researcher at the Yunnan Key Laboratory of Primate Biomedical Research,
data from this species should be very useful for curing human disease and improving human health.
Human health and longevity are major focuses for genetic engineers. The discovery and use of various synthetic nuclease launched genetic engineering in humans from a dream to an exponentially growing reality.
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A nuclease is a naturally occurring type of genetic code found in the genome of many bacteria and archaea. Nuclease are of particular interest to scientists in the field of genetic engineering because nuclease have the unique capacity to be used as “molecular scissors.” They can literally cut DNA at target areas without harming the two newly created DNA strands in any way. They’re like a real-life cut-copy-paste tool for working with genetic code.
Genetic engineers create synthetic nuclease in the lab to aid them in genetic engineering. To date, four different synthetic nuclease have been created for use in genomic editing. These are:
- Meganucleases
- Zinc finger nucleases (ZFNs)
- Transcription activator-like effector nucleases (TALENs)
- CRISPRs
CRISPRs are the newest and arguably most effective synthetic nuclease used in genetic engineering today. CRISPR stands for “Clustered Regularly Interspaced Short Palindromic Repeat,” and are used by bacteria to fight off viruses by destroying targeted DNA. By harnessing the CRISPR mechanism, geneticists revolutionized the field. According to an article entitled “The CRISPR Craze“ published in August 2013 on sciencemag.org,
In January, four research teams reported harnessing the system, called CRISPR, to target the destruction of specific genes in human cells. And in the following 8 months, various groups have used it to delete, add, activate or suppress targeted genes in human cells, mice, rats, zebrafish, bacteria, fruit flies, yeast, nematodes and crops, demonstrating broad utility for the technique. With CRISPR, scientists can create mouse models of human diseases much more quickly than before, study individual genes much faster, and easily change multiple genes in cells at once to study their interactions.
Even DuPont has used CRISPRs to create improved bacterial strains for food production. CRISPRs are now used almost ubiquitously throughout laboratories that perform genetic engineering. CRISPRs provide researchers with incredible flexibility and the ability to create a genetically modified animal in a single generation. The recent custom monkey study is a boon that will inevitably launch the industry to even greater heights.
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Researchers such as Robert Desimone, director of MIT’s McGovern Brain Institute for Brain Research, have openly expressed their interest in genetically engineering their own custom monkeys. According to Desimone,
Although mice are giving us tremendous insight into basic brain biology and the biology of the disease, there’s still a big gap in between the mouse brain and the monkey brain.
There is yet an additional gap between a monkey brain and human brain. However, the fact that direct genome editing works to create modified monkeys suggests it might also work to create genetically modified humans. CRISPR has already been used to modify human cells grown in laboratories, but it has yet to be tested on developing or developed humans. The authors conclude their statements on genetic engineering with CRISPRs with a note of prolonged optimism, announcing that,
We believe the success of this strategy in nonhuman primates gives lots of potential for its application in humans, but we think due to the safety issue, it will take a long way for expanding this strategy to human embryos.
One day genetic engineering will revolutionize the medical industry, the fashion industry, countless more industries, and then it will one day be taken for granted. The faster we can genetic engineering technology for granted, the faster I can take having night-vision and a few extra arms for granted. Let’s do this world!
Sources:
http://jgp.rupress.org/content/36/1/39.full.pdf
http://www.pnas.org/content/70/5/1293.short
http://www.sciencemag.org/content/329/5987/52
http://www.cell.com/abstract/S0092-8674%2814%2900079-8
http://www.technologyreview.com/news/523986/monkeys-modified-with-genome-editing/
http://abcnews.go.com/US/story?id=94412
http://www.nature.com/nrg/journal/v11/n3/full/nrg2749.html
http://en.wikipedia.org/wiki/Genetic_engineering#Genome_editing
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