DNA Fingerprinting- Principle, Methods, Applications


DNA stands for deoxyribonucleic acid, and it is a complex molecule that contains all of the information necessary to build and maintain an organism. All living things have DNA within their cells, and nearly every cell in a multicellular organism possesses the full set of DNA required for that organism. However, DNA does more than specify the structure and function of living things — it also serves as the primary unit of heredity in organisms of all types. In other words, whenever organisms reproduce, a portion of their DNA is passed along to their offspring. This transmission of all or part of an organism`s DNA helps ensure a certain level of continuity from one generation to the next, while still allowing for slight changes that contribute to the diversity of life.

But what, exactly, is DNA? What smaller elements make up this complex molecule, how are these elements arranged, and how is information extracted from them? DNA is basically a long molecule that contains coded instructions for the cells. Everything the cells do is coded somehow in DNA - which cells should grow and when, which cells should die and when, which cells should make hair and what color it should be. DNA is composed of a long chain of monomer nucleotides, which are the basic units of DNA. The nucleotides of DNA consist of a deoxyribose sugar molecule to which is attached a phosphate group and one of four nitrogenous bases: two purines (adenine and guanine) and two pyrimidines (cytosine and thymine). These four bases are often abbreviated as A, G, C and T. The nucleotides are joined together by covalent bonds between the phosphate of one nucleotide and the sugar of the next, forming a phosphate-sugar backbone from which the nitrogenous bases protrude.

The structure of DNA is a double-helix polymer, a spiral consisting of two DNA strands wound around each other. Each strand is complementary to the other, meaning that the bases on one strand can form hydrogen bonds with the bases on the other strand according to a specific rule: A pairs with T, and G pairs with C. This base pairing allows the strands to hold together and also enables the faithful replication of DNA during cell division. The sequence of bases along a strand determines the genetic information encoded in that strand. Different segments of DNA can code for different genes, which are instructions for making proteins or regulating cellular activities. The human genome, which is the complete set of DNA in a human cell, contains about 3 billion base pairs and about 20,000 genes.

DNA is essential for life as we know it. It stores, transmits and expresses the genetic information that guides the development and functioning of all living organisms. It also allows for variation and evolution through mutations and recombination. Understanding how DNA works can help us solve many problems in medicine, biotechnology, agriculture and forensics. In this article, we will explore the principle, methods and applications of DNA fingerprinting, a technique that uses DNA to identify individuals based on their unique genetic profiles.