Writing in Biology

We created a ten question survey addressing age, major, knowledge of genetic editing, and opinions on different areas of the topic. We provided specific statements about the use of gene editing in the treatment of genetic disorders, and had survey participants indicate to what degree they agreed or disagreed with them. We sent out the survey to students from the University of Massachusetts Amherst through Survey Monkey, which allowed for easy sharing of the survey link as well as a clear format for analyzing the results. We posted a link to the survey in a Facebook group for the clarinet section of the UMass Marching Band which consists of students of various ages and majors in order to get a variety of different responses.  

Once we got enough responses we were able to view the resulting data in graphs. We analyzed these graphs to see if there were any observable trends between college major and attitude towards the topic of using gene editing to treat genetic diseases.

With the rise of scientific issues such as genetic engineering in public debates, “science is becoming more politicized and controversial with widespread societal implications” (Rose, Korzekwa, Brossard, Scheufele & Heisler, 2017). As such, the importance of public attitudes towards these issues is increasing, as is engaging the public with these topics in order to increase knowledge and awareness (Rose, Korzekwa, Brossard, Scheufele & Heisler, 2017). People’s attitudes are influenced by their knowledge, and so people with different backgrounds will often have varying attitudes towards complex topics depending on how familiar they are with them. The University of Massachusetts Amherst has over 100 different undergraduate majors [CITATION], and presumably people in different majors will have had different levels of exposure to the topic of genome editing. In this study we investigated whether or not there is any observable connection between college major and people’s attitudes towards the use of genome editing to treat genetic disorders.

Genome-editing has been met with both celebration and skepticism from the scientific community and the general public, with concerns about the viability, ethics, and long- and short-term consequences of modifying the human genome [CITATION]. As genetic disorders are caused by DNA abnormalities, they can only be “cured” by targeting the disorder at the genomic level, recently made possible by new advances in molecular technology. Both somatic cells and germline cells can be edited, and while any changes made to the DNA of an individual's somatic cells will only affect that individual, changes made to their germline DNA could be inherited by their future children. The technology at present cannot guarantee that “unintended modifications created through an editing procedure would not result in a devastating long-term outcome such as cancer or adverse developmental effects if one were to modify a zygote” (Kohn, Porteus & Scharenberg, 2016), which has lead to mixed scientific and public opinions about its use.

Genome editing (or gene editing) is a type of genetic engineering that involves modifying a living organism’s genome. Specific regions of the genome are deliberately targeted and DNA sequences are inserted, deleted, or otherwise modified to modify the sequence at that location and alter gene function, either by preventing or enabling expression, or by changing how the gene is expressed (“Genome editing in brief: what, why and how?”, n.d.). Genetic disorders can affect both somatic (body) cells and germline cells (cells involved in reproduction, such as sperm and eggs). While genetic mutations in the DNA of somatic cells only affect the individual and cannot be inherited, changes in the germline DNA are heritable and can affect future offspring (Ormond et al. 2017)

The DNA is the foundation of variability. The different arrangements of four nitrogenous bases, thymine, adenine, guanine and cytosine, determine how cells function and what characteristics an orgamism possesses. An organism's genome contains millions of genes which code for proteins with a variety of functions. With a million possible bases comes a million possible errors. Each base in the genome has a probability of being switched out for the wrong base due to mutations from UV radiation, errors during DNA replication and even mutagenic substances. Mutations that arise from changing single bases are called point mutations and these account for numerous genetic disorders like muscular dystrophy, sickle-cell anemia, phenylketonuria etc. With the advent of CRISPR-Cas9 system, it is posisble to create double-stranded breaks that allow the integration of random sequences. This is useful in research settings where knockout mutations are the aim but for therapy, the traditional CRISPR/Cas9 machinery may only aggravate the disease. The need to change single nucleotides spurred the discovery of base editors. Base editors consist of inactive Cas9 scissors paired with a protein that catalyzes the desired base change. In order to circumvent potential revertion to the incorrect base by the cell's proof-reading machinery, the base editor creates a nick in the other strand of DNA. This marks that strand for correction, allowing the proof-reading machinery to integrate the correct complementary base without hindering the correction. 

The DNA is the foundation of variability. The different arrangements of four nitrogenous bases, thymine, adenine, guanine and cytosine, determine how cells function and what characteristics an orgamism possesses. An organism's genome contains millions of bases which code for proteins with a variety of functions. With a possible bases comes a million possible errors. Each base in the genome has a probability of being switched out for the wrong base due to mutations from UV radiation, errors during DNA replication and even mutagenic substances. Mutations that arise from changing single bases are called point mutations and these account for numerous genetic disorders muscular dystrophy, sickle-cell anemia, phenylketonuria etc. With the advent of CRISPR-Cas9 system, it is posisble to create double-stranded breaks that allow the integration of random sequences. This is useful in research settings where knockout mutations are the aim but for therapy, the traditional CRISPR/Cas9 machinery may only aggravate the disease. The need to change single nucleotides spurred the discovery of base editors. Base editors consist of inactive Cas9 scissors paired with a protein that catalyzes the desired base change. In order to circumvent potential revertion to the incorrect base by the cell's proof-reading machinery, the base editor creates a nick in the other strand of DNA. This marks that strand for correction, allowing the proof-reading machinery to integrate the correct complementary base. 

          The first study of what would come to be called aDNA was conducted in 1984, when Russ Higuchi and colleagues at the University of California, Berkeley reported that traces of DNA from a museum specimen of the Quagga not only remained in the specimen over 150 years after the death of the individual, but could be extracted and sequenced. To determine whether DNA survives and can be recovered from the remains of extinct creatures, they examined dried muscle from a museum specimen of the quagga, a zebra-like species endemic to South Africa that went extinct in 1883. Over the next two years, through investigations into natural and artificially mummified specimens, researchers confirmed that this phenomenon was not limited to relatively recent museum specimens but could apparently be replicated in a range of mummified human samples that dated as far back as several thousand years.

The three-part experiment performed by Mizokami et al. to analyze the relationship of mesophyll conductance and change in the CO2 levels enabled them to explain the characteristic of mesophyll conductance in plants (2017). As said in the beginning, there are many studies done for the stomatal conductance, but not many for mesophyll conductance. This report has given four key discoveries to understand about the mesophyll conductance behavior. Starting on 1) decrease in mesophyll conductance to increase in CO2 is independent from the stomatal conductance. 2) The different reactions observed in mesophyll conductance for CO2 levels, and ABA application concluded how mesophyll conductance uses different mechanisms to decrease depending on the external factor. 3) Mesophyll conductance reacts better in 1% O2 than 21% O2.  4) Mesophyll conductance do not react spontaneously, rather gradually to the external environment (Mizokami et al., 2017). There were experimental error such as overestimation in the intercellular concentration, how aquaporins behave, and nitrogen balance. So, to have a better result Mizokami concludes how these factors should be considered in further studies (Mizokami et al., 2017).

The second experiment was carried out to examine the mesophyll conductance responding to ABA application (Mizokami et al., 2017). This experiment was done in a similar setting to the first experiment with the investigation of the change in the CO2 levels. Mizokami et al. grew each plant, Col-0, ost1, and slac1-2 in a pot that were placed in a chamber that provided a photoperiod of eight hours, 23 degrees Celsius for day temperature, 21 degrees Celsius for night temperature, humidity of 60%, ambient CO2  of 390μmol and a Hoagland solution twice a week (Mizokami et al., 2017). In this ABA application experiment, the CO2 level in the chamber was not manipulated and stayed constant for two weeks. Mizokami et al. first made a tiny slit with a razor in the Arabidopsis thaliana’s petiole to make a space to inject the ABA solution so that the plants will not wilt (2017). They kept these plants in the dark for about 15 minutes before turning on the fluorescent lamp again to prevent the slit from embolism. After the plant is adjusted to the slit, an artificial xylem sap called AXS was injected and the fluorescent lamp in the chamber was turned on shining a 600μmol light on the plants. Then the initial photosynthetic rate was measured (Mizokami et al., 2017). When the initial photosynthetic rate and the atmospheric conditions were recorded, Mizokami et al. applied 100μl of ABA solution gradually into the same slit where they injected the AXS solution (2017). It took an hour and a half to complete this injection, and they measured the photosynthetic gas exchange parameter to compare the results from the initial data. Not only the measurements, but also ABA contents in the leaf was observed (Mizokami et al., 2017). By using liquid nitrogen to freeze the leaf and removing the veins from it, the contents were determined by using a liquid chromatograph and a mass spectrometer. Finally, to evaluate the mesophyll conductance, Mizokami et al. created an equation (Figure 1) to analyze how sensitive the mesophyll is to both ABA and CO2 levels (2017).