DNA

DNA is a term that has been used in science as well as in many parts of daily

life. The general public knows that DNA is a part of our bodies but they may

wonder what exactly is DNA? DNA is a term used for deoxyribonucleic acid and it

is the genetic material of all organisms, it is the molecule of life and it

determines all of our physical characteristics. DNA is present in every single

form of life. More than 50 years after the science of genetics was established

and the patterns of inheritance were clarified, the largest questions remained

unanswered: How are the chromosomes and their genes copied exactly from cell to

cell, and how do they direct the structure and behavior of living things?

Two American geneticists, George Wells Beadle and Edward Lawrie Tatum, provided

one of the first important clues in the early 1940s. Working with the fungi

Neurospora and Penicillium, they found that “genes direct the formation of

enzymes through the units of which they are composed.” (Annas) Each unit, a

polypeptide is produced by a specific gene. This establish the field of

molecular genetics.

The fact that chromosomes were almost entirely composed of two kinds of chemical

substances, protein and nucleic acids, had long been known. In 1944, however,

the Canadian bacteriologist Oswald Theodore Avery showed that deoxyribonucleic

acid (DNA) performed this role. He extracted DNA from one strain of bacteria

and introduced it into another strain. The second strain not only acquired

characteristics of the first but passed them on to the next generation. Each

nucleotide consists of a phosphate, a sugar known as deoxyribose, and any one of

four nitrogen-containing bases. The four nitrogen bases are adenine (A),

thymine (T), guanine (G), and cytosine (C).

In 1953 James Dewey Watson of the United States and Francis Harry Crick of

England worked out the structure of DNA. In 1962, both men earned the Nobel

Prize in physiology for their discovery. This knowledge provided understanding

how hereditary information is copied. Watson and Crick found that the DNA

molecule is composed of two long strands in the form of a double helix,

resembling a long, spiral ladder. The strands, or sides of the ladder, are made

up of alternating phosphate and sugar molecules. The nitrogen bases, joining in

pairs, act as the rungs. Each base is attached to a sugar mo...

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...ut of the nucleus.

Scientists continue to study the DNA molecule with hopes of find the secrets

that are hidden with in our own bodies. Their findings continue to aid us in

cures and the prevention of many illnesses that years ago we couldn’t solve.

Hopefully the research will soon pay off, with the cure for cancer or

Alzheimer’s Disease. DNA has also been very important in Forensic science where

it is used to identify individuals who have committed a crime. More recently,

DNA has been valuable in identifying those who were lost in the World Trade

Center disaster.

Genetic scientists working on what is known as the Human Genome Project have

been able to map all of the sequences of the three billion nucleotide base pairs

that make up the human genetic material. This will prove to be very important

and will pave the way for many life changing discoveries. This fact has caused

some controversy due to religious and moral matters because it gives man much

power over the developement of future generations. Although this may be a

concern I feel that there are many benefits in the ability we will have to do

amazing things because of these recent discoveries.