Genetic Engineering and Human Health

Objectives

My goal is to layer chemistry and biology concepts with thinking about DNA and how it can be modified prior to becoming the foods we eat. What better way to get students interested in the particle level other than thinking about what happens in our bodies? Each cell in our bodies contains DNA molecules, which are combinations of the same atoms that form water, carbon dioxide, and all other molecules. Just like simple chemical reactions which get discussed in general chemistry classes it is chemical reactions that happen in order for our DNA to make us who we are. The intent is to get students to make the connections between the biology they studied in the previous school year to some of the chemical reactions happening in their bodies to make them who they are.

I want my students to look at where their food comes from: that is, how the food we eat gets to the grocery store. From a cursory survey of my students from the previous school year many of my city students do not regularly consume fresh fruits and vegetables and have never actually thought about where those fruits and vegetables come from. They are provided with cheap prepared foods with no regard for nutritional value and have no experience with actually growing any fruits or vegetables of their own.

My hope is to not only get students to think about where our food comes from but also what it is that makes us who we are. Having grown up hearing, you are what you eat; I presume the connection there will be fairly simple to make. I also want to consider how each person has a unique DNA sequence, and how that sequence defines us as human beings. Much of our sequence is very similar, but just a tiny variation in that sequence can have drastic repercussions. By giving students the opportunity to grow and compare their own crops we will have a simple conversation starter to pique interest: the crops that are grown are not the same just as not all humans are the same, even though both the crops and we as people are made out of atoms of the same elements.

Scientists who understand DNA sequencing have been able to identify genes within chromosomes and link them to specific traits. Once they have identified a trait and where to find the genes that control it, they were also able to identify a similar trait with subtle differences from another DNA sequence. After years of research scientists have been able to modify the genetics of the DNA in plants to create genetically modified crops with preferred properties. Scientists unravel a strand of DNA, send in an enzyme to break apart the original strand, and then put it back together with a new piece of DNA linked in. This is a very basic description of how scientists change heirloom crops into GMO crops. The issue of modifying crops is fairly controversial and will be discussed by students at length specifying the following arguments:

Pros

One argument for GMO crops is that we can increase the nutritional value of crops merely by changing part of a genetic sequence but maintaining the other properties of the fruit or vegetable. Some advantages for GMO crops are increased yield, drought tolerance, salt resistance, and enhanced nutrition.

A central idea behind GM crops is that more crops can be grown in harsher conditions using less land: this could be an answer to world hunger. The world population is currently around 6 billion people but continues to grow. The expectation is that the world's population will peak around 10 billion. According to John E. Smith in Biotechnology there will need to be a substantial increase in food production, with 80% coming from developing countries, yet introducing less than 6% of new virgin soil for cultivation. Thinking back to the 60's and 70's, when faced with a similar problem, the answer scientists came up with was to increase the use of fertilizers, biocides, and irrigation. (John E. Smith pg 133) ³ It is no longer acceptable to keep spraying the foods we eat with chemicals that may be harmful, so the alternative is to change the chemistry within a plant so that the plant and not the environment in which it grows is what changes.

Agriculture continues to be the world's largest single industry in advanced societies such as the US contributing 20% of the total gross national production (John E. Smith pg 134). In order to survive as a human race, we must rely on agriculture to provide sustenance, in turn; agriculture must rely on technology to achieve productivity and profitability (pg 134.) Many countries do not produce enough food to be self sufficient for many reasons such as a lack of good agricultural practices, hostile or changing climate, or political instability. If a country is too poor to take advantage of biotechnology and new practices, companies like World Bank and European Economic Community chose to help them catch up with the times (pg 134). ⁴ The food has to come from somewhere; the issue is if it is ethically and morally right to modify the DNA of plants in order to produce it.

Cons

It is not clear that GMOs are safe, particularly because the genetic modifications may migrate. There are many questions about the unintentional migration of the genetically engineered crops, which inadvertently results in the loss of biodiversity. Historically these changes have been driven by evolution which is where some of the controversy comes into play. According to Van Den Bergh and Holley, once differences in plants are lost the resistance against insects is reduced, which may lead to an insect plague or disease. Non-targeted species may also be affected by outcrossing from domesticated species ⁵ (page 8-9). Seed companies conduct short term studies on the effectiveness of their creations but do not conduct long term studies to fully understand the repercussions of using genetically modified crops.

There needs to be comprehensive studies on pollen drift, gene flow, weed resistance, cultural imperialism, predatory multi-nations, and increasing popular mistrust ⁶. Currently 50% of the world's GMO's are grown in the United States whereas many other countries have banned the use of GMO's. Some scientists are unable to conduct experiments to fully understand the effects of GMO's due to fear of litigation. If we are going to choose whether to purchase genetically modified foods then there has to be a way to become informed consumers.

Other issues that come into play with GMO crops include the creation of superbugs, changes in biodiversity, and the creation of allergens. A superbug occurs when bacteria or viruses have developed a resistance to the chemicals available to treat them. One superbug that has recently gotten a lot of attention is MRSA, methicillin-resistant Staphylococcus aureus, which is an antibiotic resistant staph. According to Maryn McKenna in her book Superbug, the story of MRSA is the story of how we took antibiotics for granted, and failed to plan for the creative survival tactics of bacteria. Maryn also explains how our willingness to trust technology helped lead to epidemics such as MRSA. ⁷ Scientists have to continually create new solutions to changing problems like MRSA and others which may develop in the future, possibly as a result of using GMOs.