NEW METHODS OF THE STUDY OF DNA

New Methods of the Study of DNA

CHAPTER-I: INTRODUCTION

Introduction

Deoxyribonucleic acid (dna) is the complex organic molecular structure that is responsible for encoding information that passes on genetically inherited traits in living creatures. DNA is part of all eukaryotic and prokaryotic cells, in addition to a number of viruses. Kaye and George (2000) mention although the presence of DNA had been detected in the middle of the 19th century, it was not until 1953 that the Nobel Prizewinning scientists Francis Crick and James Watson determined the characteristic double helix spiral of DNA. DNA strands consist of a chain of nucleotides, which are composed of a sugar molecule (deoxyribose) attached to which are nitrogenous bases known as pyrimidines and purines, as well as a phosphate attachment. The strands are bound to each other covalently and according to a complex, but systematic set of rules. This makes for a stable arrangement in which the DNA can replicate itself by dividing the strands. Portions of each strand contain information known as genes, and these are passed on to the daughters of DNA division as a form of inheritance. The divided DNA consists of one original strand, and one newly created strand, which provides for some variation and evolution within a stable framework that reduces the possibility of entropy.

DNA double strands are combined in proteins within cells intensively, and these form chromosomes of a nature determined by the type of cell (Kaye and George, 2000). Chromosomes reside within the nuclei of eukaryotic cells and within the cytoplasm of prokaryotic cells, which do not have a nucleus confined within a membrane. DNA also resides in other parts of eukaryotic cells and may also be part of plasmids, which are self-replicating bundles of genetic material found in organisms such as bacteria. The DNA within viruses differs in that it can take either single or double-stranded forms or else may be based on ribonucleic acid (RNA). Since DNA necessarily varies between individuals through carrying genetic material from parents, it is possible to identify unique configurations in people (and animals) and create a database of DNA fingerprints. This would be of considerable assistance in forensics, although it opens up a number of civil liberties issues (Scheck, Peter and Jim, 2000). Similar technology is also being used to identify people who may be at risk of genetically transmitted diseases and medical conditions.

CHAPTER-II: LITERATURE REVIEW

English geneticist Alec Jeffreys first described a method for “typing”human DNA in 1985. Since that time, DNA typing technology has advanced rapidly, and the new DNA tests have been embraced eagerly by the criminal justice system. DNA tests are now routinely used to help identify the source of blood, semen, hair, and other biological materials found at crime scenes and to establish family relationships in cases of disputed parentage (Scheck, Peter and Jim, 2000). DNA tests have helped prosecutors obtain convictions in thousands of cases, and they have helped establish the innocence of thousands of individuals who might otherwise have become ...