Molecular evolution is the area of evolutionary biology that studies evolutionary change at the level of the DNA sequence. It includes the study of rates of sequence change, relative importance of adaptive and neutral changes, and changes in genome structure. Molecular biology is the branch of science that involves analysis of the structure, function and physiological role of various cellular biomolecules. Molecular biology basically involves molecular analysis of biological functions. Molecular biology follows a multidisciplinary approach of studying biomolecules by integrating the knowledge of biochemistry, genetics, cell biology and biophysics. Molecular biological studies provide insights into the various cellular and subcellular molecular mechanisms viz. DNA replication, transcription, translation, protein folding, DNA recombination etc. Contemporary molecular biology research incorporates the molecular analysis of the functioning of novel drugs and also the identification of specified molecular targets which can be exploited for pharmaceutical and medical applications.