History of DNA

History of DNA
Deoxyribonucleic acid or DNA is the body's container of genetically inherited instructions. These instructions manifest in a lifetime, in the form of common patterns of behavior or health problems, or psychosomatic relativity. This nucleic acid is essential for the growth, development, and functioning of all living organisms.
BiologyWise Staff
DNA on dark background
Deoxyribonucleic acid or DNA molecules store common strains of genetic information, over generations. The best way to understand its importance in evolution, is by comparing it to a blueprint or a recipe. Just like any one of the latter contain definite instructions and ingredients to churn out the desired end product, so do the Deoxyribonucleic acid molecules. This nucleic acid comprises important instructions or directives that help construct similar cell components, like RNA molecules and proteins. The acid segments that carry important genetic information are referred to as genes. Other than the genes, there are Deoxyribonucleic acid sequences that serve a structural purpose. These sequences regulate the manner in which the genetic information stored is used and executed in subsequent structures.

Deoxyribonucleic acid comprises two simple-unit polymers called nucleotides. The nucleotides have backbones built by ester-bond-fastened phosphate groups and sugars. The two strands or polymers are anti-parallel in nature, which means that they run in opposite directions. Each sugar hosts one of the four types of bases. The sequencing of the four bases and backbone, enables encoding of genetic make-up. There is a genetic code awarded to the sequencing, to make the readings easier, and specify the sequence of amino acids present within the proteins of each DNA strand. Within each cell, the DNA comprises chromosomes or X-shaped structures. When a cell divides, the chromosomes are duplicated. This results in the commonality traits handed down generations of animals, plants, fungi, and protists.

Research Revelations by James D. Watson and Francis Crick

The discovery of Deoxyribonucleic acid dates back to 1869, when the cell component was first isolated by Friedrich Miescher, a Swiss physician. Miescher discovered the microscopic substance when examining discarded surgical bandages. Since he found the component as a part of the cell nuclei, he recorded it under the name 'nuclein'. It was not until 1919 that the base, phosphate and sugar nucleotide unit of Deoxyribonucleic acid, was discovered by Phoebus Levene. Levene's records mentioned that DNA strands comprised a 'string' of nucleotide units. He observed that these units were linked via phosphate groups. However, Levene's misconception was that the DNA chain, which he called a string, was short and repetitive in nature.

Frederick Griffith discovered the possibility of mixing smooth bacteria with the live, rough form, in 1928, a discovery that was soon to be linked with the DNA structure. The first Deoxyribonucleic acid x-ray diffraction patterns were discovered by William Astbury, in 1937. The Frederick Griffith discovery was used to generate the possibility that Deoxyribonucleic acid carried genetic information, irrespective of its state. This clearly defined it as the 'transforming principle' of cells, via the Avery-MacLeod-McCarty experiment in 1943. It was in 1952, that Alfred Hershey and Martha Chase confirmed its role in heredity. The Hershey-Chase experiment proved that DNA is indeed the genetic material of T2 phage.

A year later, in 1953, the double-helix model of Deoxyribonucleic acid structure was publicized by James D. Watson and Francis Crick. However, the double-helix model was then illustrated with a single x-ray diffraction image. It was Maurice Wilkins analysis that proved the 'in-vivo double-helical DNA configurations' in 1962. The discovery earned Watson, Crick, and Wilkins, the Nobel Prize in Physiology or Medicine. In 1957, Crick observed and publicized the relationship between DNA, RNA, and proteins, via the 'adaptor hypothesis'. Confirmation of the Deoxyribonucleic acid replication mechanism in 1958 and the non-overlapping base triplets or codons, have helped decipher the mystery in 'genetic code'.