Discovery of DNA

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1. Gregor Mendel was an Austrian monk, who lived from 1822 to 1884 (1). He first discovered the rules of genetics (1).

Mendel, known as the ‘Father of Genetics’, started to investigate variation, hereditary, and the evolution of plants (8). He did experiments with pea plants, and carefully analysed seven plant characteristics (e.g. plant height) (8). Mendel discovered that offspring retained essential traits from their parents, and this instigated the concept of hereditary (9). The results from his pea experiments are known today as the Laws of Hereditary (8).

2. a) A gene is a section of DNA that ‘codes’ for a particular protein – proteins determine how an organism looks and acts (2, 7). A gene carries information about how living things grow and carry out their life processes (6).

b) Genetic engineering is the process of moving genes from one organism to another (3, 14).

For example, genetic engineering is used today in rice production (4). Natural rice lacks vitamin A (4). A shortage of vitamin A can cause optical problems (5). Scientists take a beta-carotene production gene from carrot plants, and transfer it into rice plants (4). Human bodies are able to turn the resulting beta-carotene into vitamin A (5).

3. a) Rosalind Franklin used x-ray crystallography to investigate the structure of DNA (15). The technique involved exposing a crystal to x-rays to produce a diffraction pattern (15). It was possible to reconstruct the positions of the atoms that make up DNA (15). Franklin discovered that DNA existed in two forms – A and B (15). As these were mixed together, the diffraction patterns were impossible to interpret (15).

Rosalind, however, succeeded in determining a way of separating the two forms (15). This provided DNA crystals pure enough to create interpretable diffraction patterns, and using a combination of crystallographic theory and chemical reasoning, she discovered important facts about DNA structure (15).

b) James Watson and Francis Crick used x-ray crystallography data, produced by Franklin, to decipher DNA’s structure (16). From other scientists, they already knew the following: DNA was made up of nucleotides; there were four bases in a DNA molecule – A, C, G, and T; and the basic structure of DNA was helical (16). By using nucleotide molecules made of wire, Watson and Crick assembled DNA in a manner which confirmed these existing scientific particulars (16).

Watson and Crick then proposed that the DNA molecule was a double helix, shaped like a long, twisted ladder with rungs (called nucleotides) (6).

4. a) The human genome project was a 13-year effort coordinated by the US Department of Energy and the National Institutes of Health (7). It began in 1990, and was planned to last for fifteen years, but rapid technological advances accelerated the completion date to 2003 (7). The project was initiated primarily to identify all genes in human DNA, and to determine the sequences of bases within human DNA (7).

A unique feature of the project: the first large scientific undertaking to address potential ethical, legal, and social issues that transpired (7). Another important aspect was the US government’s dedication to transfer technology to the private sector (7). By licensing technologies to private companies, and awarding grants for innovative research, the project advanced the multi-billion dollar biotechnology industry, and consequently, promoted the development of new and useful medical applications (7).

b) Human genome understanding has enabled researchers to identify anomalies in genes, which contribute to diseases (17). The goal is to use this information, and develop new ways to counteract multiple diseases that affect humankind (17). Furthermore, researchers are revolutionizing drug design; drugs are being created on the basis of gene sequence and protein structure, as opposed to the traditional trial-and-error method (17). The potential drugs, targeting specific parts of the body, promise to have fewer side effects than many of today’s medicines (17). Moreover, a rapidly developing field is the idea of using normal genes to cure diseases (e.g. adding a gene that suppresses tumour growth) (17).

5. a) Reasons for the genetic engineering of humans:

* Humans can be produced with new and useful features (4).

* Gene therapy – the medical treatment of a disease by repairing or replacing defective genes, or introducing therapeutic genes to fight the disease (10).

Reasons against the genetic engineering of humans:

* As there isn’t enough scientific understanding of their impact on the environment, the inserted gene might have unexpected harmful effects (4, 13)

* Loss of identity and individuality (11).

* There may be adverse social implications (12). Those wealthy or privileged enough may engineer themselves or their children to have special characteristics, which could lead to a genetic aristocracy (e.g. increased memory and intelligence (12). These genetic enhancements would add to the burden of the inequality between rich and poor in today’s society (12).

b) I believe that genetic engineering of humans shouldn’t be allowed. The predominant reason for this is because I’m a theist and feel that genetic engineering is a form of ‘playing God’, which is immoral (4). God’s creatures shouldn’t be interfered with, but left alone (4). Human genetic engineering leads to man usurping God as the almighty creator and designer of life (11). An engineered child would no longer be a gift from God; instead, a product manufactured by a scientist (11).

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