Project 3 Rough Draft:The Affect of Genetic Engineering on Human Life Expectancy

The human body is fascinating. It is physically strong, chemically efficient, ultimately dependable, and is designed by a polymer comprised of four different compounds. This polymer, known as deoxyribonucleic acid (DNA), is the blueprint for every cell inside of us, and after the discovery of its molecular structure in 1953, the scientific community scrambled to unravel the answer behind its eccentric, trait coding capabilities (Nicholl 6). Since then multiple fields, the most important being genetic engineering, have emerged and provided promising developments for mankind. In fact, since 1900 we have seen a 30 year increase in human life expectancy alone (Scientific American). This statistic affirms the significance of developments made in the field of genetic engineering, and suggests that the further development of genetic engineering practices will influence an increase in human longevity.

DNA
 Image: iStockPhoto

Although the molecular structure of DNA was discovered in the early 1950s, progress toward developing techniques for gene manipulation was hindered until the early 1970s (Nicholl 6). According to Nicholl, the cause was a lack of technological advancement, and only after breakthroughs were made could progression toward these developments resume (6). To scientists relief, the breakthroughs arrived through the isolation of DNA Ligase and a restriction enzyme (Nicholl 6). While both molecules have separate functions in the grand scheme of recombinant DNA production—Ligase binds two separate DNA strands together, while the restriction enzyme specializes in cutting DNA at designated positions like a pair of scissors—together they make up the foundation of recombinant DNA technology, the splicing of one organism's DNA into a new host (Nicholl 6). As Jackson and Stich describe, "molecular biologists learned how to remove bits of genetic material (DNA) from various organisms and insert them into bacteria" (xiii). As the bacterial cells divided, the newly incorporated segment of DNA would be replicated along with the original bacterial genome, and could possibly be expressed depending on the type of gene inserted. "Recombinant DNA technology...provided scientists with a singularly powerful tool for studying the basic mechanisms of genetics in all organisms" (Jackson and Stich xiii).

Although genetic engineering hinges on the advancement of modern technology, it is important to note that its concepts have been around for thousands of years (Genetically Modified Organism). Sure, while it's obvious that medieval Europe did not possess the capabilities to splice together DNA from two separate organisms, they did understand that by breeding two animals together (both with a desired trait) they could produce offspring that would likely posses the desired trait as well.

In nature, this occurs even more readily and without human interference. Known more commonly as natural selection, an animal with a beneficial trait is more likely to survive and reproduce than one without the trait. Imagine a species of drab colored and white colored moths. In order to avoid predators, the moth must be able to blend in with its surroundings. For the drab colored moth, this is a simple task, yet for the white colored moth, it is much more difficult. Because of their lack of camouflage, the white colored moths will be eaten more frequently, while the drab colored will survive longer and consequently have a greater opportunity to reproduce. In the end, the drab colored trait will grow to dominate the moth species.  

Research on "Flavr Savr" tomatoes at UC Berkley

While natural selection plays a large role in the selection of a species traits, current human intervention through genetic engineering has allowed a species to almost evolve independently of its environment. The key difference here is that in nature, an organism can only reproduce with another organism of the same or a closely related species. In the hands of a geneticist, however, any desirable trait can be taken and inserted into another individual. In 1994 the "Flavr Savr" Tomato was the first genetically modified product to be tested by the Food and Drug Administration (FDA) (Genetically Modified Organism). It was soon after released for commercial consumption, and because the modified tomatoes were resistant to "fruit softening," they could be transported more easily and were thus in high demand (Bruening and Lyons). The idea began when engineers at Calgene Inc. noticed that from the time ripened tomatoes were picked and transported to stores across the country, many had had become soft (Genetically Modified Organism). The protein known as polygalacturonase (PG), was identified as the compound responsible for dissolving pectin, a protein responsible for the structural strength in tomato cell walls. After making this discovery, the Calgene Inc. engineers worked on developing a way to silence the gene that produced PG (Genetically Modified Organism). They eventually came up with a PG-antisense gene and inserted it into a line of waiting tomatoes (Bruening and Lyons). Some tomatoes were detected to produce as little as 1% of the original levels of PG, and lasted significantly longer from farm to shelf (Bruening and Lyons). Though while the "Flavr Savr" tomato succeeded in proving that genetically modified plants could be marketed commercially, due to high production and distribution costs, the tomatoes never became a profitable product (Bruening and Lyons).

Although an organism may be modified by invasive genetic modification to produce a desired result, less invasive procedures may be used when choosing traits for our children. As Leon Kass M.D. describes, "this approach, less radical or complete in its power to control, would not introduce new genes, but would merely select positively among those that occur naturally." The process depends on in vitro fertilization (IVF) and screens unborn babies for desirable or undesirable traits (Kass). Known as preimplantation genetic diagnosis (PGD), twelve eggs are fertilized and allowed to grow until they reach the four-cell or ten-cell stage. Then, one or two cells are withdrawn, and the DNA extracted is amplified by polymerase chain reaction (PCR), and then analyzed for several genetic disorders. Only those embryos that are not found to have genetic disorders are allowed to be transplanted into the mother. From here, the fetus will mature and will be delivered in due time as a regular baby.

Though the intentional examination of a fetus for genetic disorders may sound grotesque, the practice is generally limited to couples who have a higher chance of giving birth to a child with a genetic disorder (Kass). By screening the viable children in this manner, the chance that a child with a birth defect will get through is minuscule, which will help to prevent the need for prenatal care and possible abortion (Kass).

With the screening of human fetuses through PGD already a current development of genetic engineering, we wonder what new advancements will be next to develop. According to the President's Council on Bioethics, the next most foreseeable step is to develop a way to produce "better children" (Kass). While it seems that invasive, genetic engineering procedures would be required to produce children with superior traits, the process is actually quite simple. By changing the objective of PGD from child screening to "baby improving," fetuses with beneficial traits would be selected. This process is simply a form of natural selection, though we must ask ourselves 'are we going to far in allowing parents to choose from a list of several possibilities what their children will look like?'

With the possibility of choosing genetically superior children imminent, we should also ask ourselves if such improvements to the human body will lead to immortality. Though this would be considered an extreme form of genetic engineering, human immortality could theoretically be possible with the combination of "biotechnology, molecular nanotechnologies, artificial inteligence and other new types of cognitive tools" (Farrar).

Works Cited

Ballantyne, Coco. Life From Scratch? Digital image. Scientific American. Scientific American, 24 Jan. 2008. Web. 27 Mar. 2011. <http://tinyurl.com/4hfaa9r>.

Bruening G., and J. M. Lyons. Research to control the ripening of tomatoes continues. At UC Berkley, Athanasios Theologis and colleagues have identified and blocked a gene responsible for ripening. Digital image. California Agriculture. University of California, July-Aug. 2000. Web. 27 Mar. 2011. <http://tinyurl.com/6cddoow>

Bruening, G., and J. M. Lyons. "The Case of the FLAVR SAVR Tomato." California Agriculture. University of California, July-Aug. 2000. Web. 27 Mar. 2011. <http://tinyurl.com/475j7f3>.

Farrar, Lara. "Scientists: Humans and Machines Will Merge in Future." CNN Tech. CNN, 15 Jan. 2008. Web. 15 Mar. 2011 <http://tinyurl.com/5u2azya>

"Genetically Modified Organism." Environmental Encylopedia. Gale Opposing Viewpoints In Context, 21 Oct. 2010. Web. 15 Mar. 2011. <http://tinyurl.com/4z59zpt>.

Hans Rosling's 200 Contries, 200 Years, 4 Minutes - The Joy of Stats - BBC Four. Dir. Dan Hillman. Prod. Dan Hillman and Archie Baron. Perf. Hans Rosling. YouTube. BBC, 26 Nov. 2010. Web. 27 Mar. 2011. <http://tinyurl.com/23dt9kn>.

Jackson, David A., and Stephen P. Stich, eds. The Recombinant DNA Debate. Englewood Cliffs: Prentice-Hall, 1979. Print

Kass M.D., Leon R. Beyond Therapy: Biotechnology and the Pursuit of Happiness. Rep. LSU Law Center. Oct. 2003. Web. 15 Mar. 2011. <http://tinyurl.com/45lhjy9>.

National Council of the Churches of Christ/USA. Genetic Engineering: Social and Ethical Consequences. New York: Pilgrim, 1984. Print.

Nicholl, Desmond S. T. An Introduction to Genetic Engineering. 3rd ed. Cambridge: Cambridge UP, 2008. Print.

Scientific American. "Life Expectancy." Scientific American. Scientific American, 13 May 2002. Web. 27 Mar. 2011. <http://tinyurl.com/4lz4uzt>.