While molecular biology was established as an official branch of science in the 1930s, the term wasn't coined until 1938 by Warren Weaver. At the time, Weaver was the director of Natural Sciences for the Rockefeller Foundation and believed that biology was about to undergo significant change due to recent advancements in technology such as X-ray crystallography.Molecular biology arose as an attempt to answer the questions regarding the mechanisms of genetic inheritance and the structure of a gene. In 1953, James Watson and Francis Crick published the double helical structure of DNA courtesy of the X-ray crystallography work done by Rosalind Franklin and Maurice Wilkins. Watson and Crick described the structure of DNA and the interactions within the molecule. This publication jump-started research into molecular biology and increased interest in the subject Polymerase chain reaction (PCR) is an extremely versatile technique for copying DNA. In brief, PCR allows a specific DNA sequence to be copied or modified in predetermined ways. The reaction is extremely powerful and under perfect conditions could amplify one DNA molecule to become 1.07 billion molecules in less than two hours. The PCR technique can be used to introduce restriction enzyme sites to ends of DNA molecules, or to mutate particular bases of DNA, the latter is a method referred to as site-directed mutagenesis. PCR can also be used to determine whether a particular DNA fragment is found in a cDNA library. PCR has many variations, like reverse transcription PCR (RT-PCR) for amplification of RNA, and, more recently, quantitative PCR which allow for quantitative measurement of DNA or RNA molecules.Citations are important for a journal to get impact factor. Impact factor is a measure reflecting the average number of citations to recent articles published in the journal. The impact of the journal is influenced by impact factor, the journals with high impact factor are considered more important than those with lower ones. To increase the visibility and ease of use of open access scientific and scholarly journals PrimeOA Publications top online publishing journals are indexed in different indexing and archiving services. Indexing provides easy access of the article online.