DNA structure, function, and biological significance

¶ … DNA, which to some of you probably sounds like some kind of esoteric scientific research; or maybe others of you understand DNA as part of the basic human building blocks of biology; and surely all of us are aware of DNA in the context of crime lab stories we see on TV and read about in the newspapers. Prisoners are being set free thanks to DNA evidence that clears them of hideous crimes.

Let me assure you, all three of those general categories about DNA are correct, so thank you for your attention as I try to explain for you: a) what DNA really is; b) how it was discovered (or uncovered might be a better word); c) who did the major work in finding the DNA code for all life; and d) lastly, and perhaps most pertinent in terms of our society, what role DNA plays in the criminal justice system.

Understanding what role DNA science has played, and will continue to play, in our society, is very important, and I believe that every citizen who has an interest in important discoveries and tools for discovery - many that make our lives better - will want to know something significant about DNA.

BODY of SPEECH

The most pertinent thing we should look at first is of course the question of JUST WHAT IS DNA? We know it is in all living things, from trees to frogs to insects all the way up the chain to we humans. But what is it? According to the respected Web site www.about.com, the editors say DNA is "an acronym for DEOXYRIBONNUCLEIC ACID...a code used within cells to form proteins." Does that make sense? Let's look at the definition from www.medicinenet.com:"DNA is one of two types of molecules that encode genetic information. The other is RNA." So, in humans, DNA is the genetic material that defines us, and in most other living organisms, RNA is the generic material and DNA is transcribed from RNA. Make sense so far?

HOW DID the EARTH BEGIN and WHEN WAS DNA DISCOVERED? First, let's go back in time to the origins of the universe, to get a total historical perspective. The earth was "born" about FOUR-and-a-HALF BILLION years ago, according to the best scientific estimates, printed in the Taipei Times on Sunday, October 15. Earth and the sun and our solar system were born in a "whirlwind of gas and dust" about NINE BILLION YEARS after the BIG BANG, according to science journalist Christian De Duve (writing in the Taipei Times).

Now let me quickly mention that if you are a strict believer in "creationism" please don't be offended by my speech at this point, please keep an open mind, because I'm referring to REAL OBJECTIVE PROVABLE SCIENCE. I'm not challenging anyone's religious beliefs. Okay? Well, a HALF-BILLION years after our planet Earth was born, life began to emerge in primitive organisms. Microbes, plants, fungi - and much later animals and humans - all began to evolve from sulfurous, metal-laden and volcanic waters, De Duve explains. Today, scientists know that CHEMISTRY is the "essence of life" and that ENZYMES and ENERGY get power from SUNLIGHT and their power is REPLICATED (they make copies of themselves) through DNA and RNA.

The Cold Springs Harbor Laboratory on Long Island, NY, home of the Dolan DNA Learning Center, explains that GENETICS is a field of science that was founded by GREGOR MENDEL. Remember one of the definitions of DNA is that it encodes "genetic information"? Mendel, who was a Augustinian monk living in what is now the Czech Republic, had a garden and he grew pea plants. In 1866, Mendel discovered that there are "recessive" and "dominant" traits in plants, paving the way for understanding how genes work in predictable ways, and plowing the ground for later science, although his work wasn't "discovered" until 1900. In 1944, three scientists at the Rockefeller Institute in New York discovered that DNA is the carrier of the genetic information within the body.

In the early 1950s, scientists were by now aware that DNA was genetic material and that is was an acid made up of sugars, phosphate groups, and "equally matches bases," the Dolan center points out. That was all well and good, but the big question remained: WHAT WAS NATURE'S GENETIC CODE?

The man most responsible for "breaking the genetic code" was MARSHALL NIRENBERG in 1961; but "breaking it" (or identifying it) was only part of the puzzle. And then in 1965, NIRENBERG (working at the National Institutes of Health in Washington, D.C.) was credited with "mapping" the genetic code for DNA. Mapping is basically understanding the logic of the code, how it works, how to read it, why it is logical; and for his hard work, along with two other scientists, NIRENBERG won the 1968 NOBEL PRIZE in PHYSIOLOGY or MEDICINE.