What Is DNA?
DNA is the word we hear most about when we are discussing gene sequencing, or for that matter, if we are watching a crime show on TV. I venture to guess that there is no one who has not heard the term. DNA is a shortened term for the nucleic acid molecule deoxyribonucleic acid. Now that's a mouthful!
MSN Encarta defines this as follows: substance carrying organism's genetic information: a nucleic acid molecule in the form of a twisted double strand (double helix) that is the major component of chromosomes and carries genetic information. DNA is found in all living organisms except some viruses, reproduces itself and is the means by which hereditary characteristics pass from one generation to the next.--brackets are mine.
There are four letters that make up the genetic code. They are A,C,G,T. These are arranged in many different combinations to make up genes and there are millions of these in a chromosome. These letters are called bases. The 'A' is short for adenine, 'C' is short for cytosine, 'G' is short for guanine and 'T' is short for thymine. Here is an example of a DNA sequence: ATCCGAAGGTCCAAC. It is like trying to read a foreign language that is not even broken up into words.
The DNA that makes up a chromosome is in the form of genes and what is called non-coding DNA sequences, just to confuse the subject a little more. So now you are trying to read a foreign language that is not broken up into words, but also has nonsense letters thrown in randomly. A tall task to say the least. All humans share about 99.9% of the same genetic make up. It is that .1% that makes us different from one another.
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