Gene flow is the source of genetic variation. Gene flow can be defined as the, introduction of new alleles to a population. Normally, this is because of simple migration. In this, new individuals of similar species enter into a population. Environmental conditions in their already existing home may have favored different forms of traits. Alleles belongs to these traits would be different from the alleles present in host population. When the new individuals interbreed with the host population, they produce new form of genes which is responsible for particular traits. The impact factor of journal provides quantitative assessment tool for grading, evaluating, sorting and comparing journals of similar kind. It reflects the average number of citations to recent articles published in science and social science journals in a particular year or period, and is frequently used as a proxy for the relative importance of a journal within its field. It is first devised by Eugene Garfield, the founder of the InstPharmacologyitute for Scientific Information. The impact factor of a journal is evaluated by dividing the number of current year citations to the source items published in that journal during the previous two years. 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.