As autonomous entities with our own agency, we have control over a huge portion of our lives; may it be our interactions with others or our food choice, our cognition and autonomy has allowed us to dictate our own fortune. Unfortunately for some, the aforementioned freedom becomes heavily curtailed by the presence of genetic diseases/disorders – one of the few aspects of fate that we are almost helpless to. Millions of people world-wide inherit some sort of disease due to kinship, forever condemned to a lifestyle they never consented to. Within the present unit of hereditary genetics and genetic engineering, we often discussed the prospect of utilizing genetic recombination to cure a multitude of different genetics-based diseases. Due to the brevity on the topic, and the heavy implications of the field, I was immediately captivated by the concept of genetic manipulation and engineering; questions regarding the efficacy and potency of the aforementioned mechanisms, in addition to their ethical grounding, has inspired me to dedicate the February blog post towards biotechnology and its pathological implications. Beyond the assignment, recombination and bio-manipulation lies even closer to heart as certain family members (overseas) have been diagnosed with mild genetics-linked diseases; now, the blog’s discourse can finally act as a springboard for discussion, while simultaneously acknowledging the hopeful future for all those impacted by hereditary conditions. In addition, my one true aspiration involves medicine and applied biology; as I will eventually enter the professional field of genealogy, the issue regarding biotechnology and bio-manipulation weighs even more heavily in my mind.
Out of all the different types of hereditary diseases in the world, this blog post will specifically focus on the devastating effects of mitochondrial disease. As a brief overview, mitochondrial disease involves mutations in the genetic composition of mitochondrial dna (independent dna located in the mitochondria). Due to the principles of prenatal development, all of our mitochondrial dna derives from the mother’s cytoplasm; thus, once the mother develops mutations within the mitochondrial dna of her gametes, there is little escape from a life of mitochondrial disease. According to the Council of Responsible Genetics, “Mitochondrial disease is a genetic disorder that can cause a variety of malfunctions throughout the body, including stunted growth, an increased risk of infection, diabetes, disease of the heart, liver, and kidneys, visual and auditory deficits, and loss of coordination and muscle weakness, various neurological problems, and seizures. Most symptoms affect children before the age of 10, though mitochondrial malfunctions can play a role in age-related diseases as well, such as multiple sclerosis and Parkinson’s disease.4,5 Approximately 1 in 10,000 people suffer from some form of mitochondrial disease today, and as many as 1 in 200 are carriers” (Council of Responsible Genetics n.d.). Afflicting as many as 1 in 10,000, mitochondrial diseases have an extremely wide-spread scope in the forms of a plethora of diseases. Diseases such as mitochondrial myopathy, diabetes mellitus, leber’s hereditary optic neuropathy, wolff-parkinson-white syndrome, leigh syndrome, subacute sclerosing encephalopathy, neuropathy, ataxia, retinitis pigmentosa, ptosis, myoneurogenic gastrointestinal encephalopathy, myoclonic epilepsy ragged red fibers, etc. are all mitochondrial diseases impacting the general population. To this day, mothers afflicted with the aforementioned pathologies have no choice but to refrain from having children.
Recently, advancements and breakthroughs in applied genetics have provided a bit of sunshine amidst all the hereditary “gloom”, presenting afflicted mothers with another option and a new life. In order to avoid the passage of mitochondrial dna to the offspring, major research labs have successfully conducted in-vitro fusion of egg and donor mitochondrial dna: “Using this technique, the donor nuclear DNA is extracted from the donor egg, leaving only the donor mitochondrial DNA. Then, the fertilized nuclear DNA from the mother’s egg is extracted and placed into the donor egg. The end result is a donor egg, containing donor mitochondrial DNA and the nuclear DNA of the intended parents. Developers of this technique claim the child produced would express the genetic traits from her intended parents, but possess the donor’s mitochondria” (Council of Responsible Genetics n.d.). With the original genetic information from the afflicted egg implanted in a “surrogate” egg containing only cytoplasmic contents, the impacts of mutated mitochondrial dna can be avoided while still creating off springs that genetically “belong” with the parents. With the aforementioned technology, millions of mothers world-wide will be granted a second chance at raising a child of their own.
Despite the simplistic description of mitochondrial dna transfer, the genetic engineering behind the process is extremely messy. While initial lab results have been positive, the impacts of mitochondrial dna transfer on neonatal babies can be extremely volatile. The Council for Responsible Genetics (CRP) have conducted analysis on the efficacy and ethicality of mitochondrial dna transfer with “studies [that] tracked the effects of MR only to the age of three. Studies in mice and other animals have suggested that harmful effects may not become apparent until adulthood and that problems from swapping mitochondria show up disproportionately in males and often affect fertility” (Council for Responsible Genetics n.d.). Thus, children born from mitochondrial dna transfer have the possibility of possessing more detrimental pathologies than the genetic disease, casting them into the same boat as before the intervention. In addition, several other ethical questions have been raised against the implementation of the dna transfer method. DNA transfer involves the alteration of entire lineage’s mitochondrial dna, changing thousands of years’ worth of genetic kinship without consent. In addition, mitochondrial dna have been found to impact the behavior of children after they have reached a considerable age; manipulating the genetic information inevitably manipulates the offspring’s composition, behavior, and psychology. What’s more, “A secondary line of criticism is the fear that genetic engineering techniques like mitochondrial DNA transfer will lead to genetic engineering for enhancement purposes rather than purely medical ones, acting as a “gateway” genetic engineering technique that could lead to eugenic applications. Some critics of mitochondrial DNA transfer also feel that interfering with something as powerful as mitochondrial DNA would be essentially “playing God.”44 They believe that once we take the first step into modifying the genome, it will be a slippery slope to continue along this path and begin allowing parents to choose “desirable” traits for their children—such as high intelligence, height, and specific hair colors.” (Council for Responsible Genetics n.d.).
Taking into consideration all of the potential benefits and detriments of mitochondrial dna transfer, the technique nevertheless exists as one of humanity’s best chance against mitochondrial pathologies. Other questions such as implementation, cost, and ethics, however, cannot go unconsidered. How much of your child will actually be “yours” if the mitochondrial dna is from a donor? What is the projected cost of mitochondrial dna transfer? Will the UK (and more importantly, the world) ever legalize the usage of the new method? Hopefully, these questions will be answered as research on mitochondrial dna transfer proliferates through the biological community, and as I trudge deeper into the topical literature. Until next time!
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Council for Responsible Genetics, n.d. Human Genetic Engineering Current Science and Ethical Implications. Retrieved from: http://www.councilforresponsiblegenetics.org/pagedocuments/yn3rbrq4go.pdf