DNA Identity

Worried whether your name is too common for someone as special as you are? Not a problem. Biotechnology offers a new solution for an identity crisis- The DNA.
DNA short for Deoxyribonucleic Acid is a 2 metre long chemical sequence present in each cell of our bodies. This is a chemical that determines our characteristics- from our physical appearance to our emotional nature. Sequences of DNA differ from person to person, but every cell within the same person contains the same sequence of DNA. So, our hair, blood, skin and all of the other cells in our body are exactly the same at the molecular level.

To be a little more scientific- DNA Skelton is made up of sugar molecules. These sugar molecules are attached to phosphate groups. These phosphate groups are attached to nitrogen bases which are of four kinds- Adenine (A), Cytosine (C) Guanine (G) and Thymine (T). So each step of a DNA staircase is sugar-phosphate-nitrogen base. This combination is called a nucleotide. A collection of these make a strand of DNA, and two nucleotides complete a single step of DNA. These steps are scientifically called, base pairs. Also, this basic order is common to all living organisms!! So the difference lies only in the positions of A, C, G, T or the length of DNA so formed.

So if 26 letters are used to name one person, biotechnologists use only a sequence of four alphabets A, T, C, and G to determine the whole genetic sequence of any living organism. Hence each person has a different DNA identity, even if his name is shared by many!

Biotechnologists determine the sequence of DNA of a person and hence create his own DNA identity, if they are provided with even small amount of cells of the person in question. This comes in very handy when police are investigating a crime. If a person left a strand of hair, a drop of blood or any other cells at a crime scene, the police will know that, that person was there.

But the problem arises, with the extraction of DNA and its handling. It becomes very probable that the DNA they receive is in such nano amounts that it is hard to study it. So scientists amplify or make million copies of the given DNA using a machine called PCR (Polymerase Chain reaction). Now since the DNA sequence is very large, it is cut by Molecular scissor enzymes called Restriction enzymes in small and convenient sizes and are then sequenced and studied intensively.

After the sequence is formed, a DNA identity is created which in turn is used for a large number of purposes.

Crime fighters use this information to prove whether a suspect is a criminal or to find the criminal itself. Doctors use this information to find the cause of certain diseases that are determined genetically. DNA fingerprints are also used to determine the identity of a child’s parents if they are unknown. Since the child inherits a DNA formed by both his parents’ DNA, his DNA pattern will resemble his parents’ DNA pattern in many aspects.

Last year, Mr. Craig Venter of Celera Genomics became the first man on earth to have his 3 million base pair long DNA- sequenced in all aspects. This sequencing resulted in deeper understanding of our genetic material, and how much it differs from person to person. Also technological advancements help us to find new methods to sequence and analyse DNA in a simpler manner. If the reason of any health problem is indicated by the DNA sequence, then methods of altering it are also under research.
The problem lies with this point onwards. Whether it is appropriate to alter the naturally present DNA to something of our own choice? After Genetically Modified Crops, are Genetically Modified Humans possible?
Shambhavi Sharan

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