Daily RC Article 28

rDNA

Paragraph 1

After thirty years of investigation into cell genetics, researchers made startling discoveries in the 1960s and early 1970s which culminated in the development of processes, collectively known as recombinant deoxyribonucleic acid (rDNA) technology, for the active manipulation of a cell’s genetic code. The technology has created excitement and controversy because it involves altering DNA—which contains the building blocks of the genetic code.

Paragraph 2

Using rDNA technology, scientists can transfer a portion of the DNA from one organism to a single living cell of another. The scientist chemically “snips” the DNA chain of the host cell at a predetermined point and attaches another piece of DNA from a donor cell at that place, creating a completely new organism.

Paragraph 3

Proponents of rDNA research and development claim that it will allow scientists to find cures for disease and to better understand how genetic information controls an organism’s development. They also see many other potentially practical benefits, especially in the pharmaceutical industry. Some corporations employing the new technology even claim that by the end of the century all major diseases will be treated with drugs derived from microorganisms created through rDNA technology. Pharmaceutical products already developed, but not yet marketed, indicate that these predictions may be realized.

Paragraph 4

Proponents also cite nonmedical applications for this technology. Energy production and waste disposal may benefit: genetically altered organisms could convert sewage and other organic material into methane fuel. Agriculture might also take advantage of rDNA technology to produce new varieties of crops that resist foul weather, pests, and the effects of poor soil.

Paragraph 5

A major concern of the critics of rDNA research is that genetically altered microorganisms might escape from the laboratory. Because these microorganisms are laboratory creations that, in all probability, do not occur in nature, their interaction with the natural world cannot be predicted with certainty. It is possible that they could cause previously unknown perhaps incurable, diseases. The effect of genetically altered microorganisms on the world’s microbiological predator-prey relationships is another potentially serious problem pointed out by the opponents of rDNA research. Introducing a new species may disrupt or even destroy the existing ecosystem. The collapse of interdependent relationships among species, extrapolated to its extreme, could eventually result in the destruction of humanity.

Topic and Scope:

Recombinant deoxyribonucleic acid; specifically, the controversy surrounding rDNA research’s potential effects.

Purpose and Main Idea:

The author comes across as neither advocate nor critic of this technology, despite acknowledging both its potential benefits and hazards. The author’s intent, it seems, is to set out both sides of a controversial issue.

Paragraph Structure:

The first paragraph tells us that the development of rDNA technology “has created excitement and controversy” in the scientific world because it permits scientists to engage in genetic engineering.

Paragraph 2 gives us a bit of information about the technology itself.

The third and fourth paragraphs describe the potential benefits of this technology, while the fifth and sixth paragraph describes its potential hazards.

The Big Picture:

The information described above is all you really need to take away from this passage. As usual, there are a lot of details. Note where they appear, but don’t try to memorize them. Remember, always read for purpose and structure rather than for content. The former two are what will get you the points.
When you see an unfamiliar scientific term like “recombinant deoxyribonucleic acid,” how should you react? Should you freak out? Should you hyperventilate? Of course not! What you should do is come up with a simple reference for the term. Here, the passage does it for you by shortening recombinant deoxyribonucleic acid to just rDNA. But it won’t always be that convenient; sometimes you’re going to have to do the work yourself. If that’s the case, treat these words like you would, say, strange names in a logic game.
Science passages aren’t more difficult than social science or humanities passages. In fact, if you don’t let unfamiliar terms intimidate you, they’re often quite straightforward. Don’t try to deal with scientific terminology on the scientifically-minded author’s own terms: reduce scientific terms to your own, simpler ones.

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