It can be defined as a place of numerous related genes which is created by doubling a single novel gene with same biochemical functions. Genes are categorized into families on the basis of mutual nucleotide or protein sequences. If a gene of a gene family instructs proteins, the word protein family is frequently used in a similar manner to gene family. The top open access journals are peer reviewed scholarly journals of Family Medicine and Medical Science Research. The top open access journals are freely available on the public internet domain, allowing any end users to read, download, copy, distribute, prink, search or link to the full texts of the articles. These provide high quality, meticulously reviewed and rapid publication, to cater the insistent need of scientific community. These journals are indexed with all their citations noted. The top open access journals are indexed in MEDLINE, PUBMED, SCOPUS, COPERNICUS, CAS, EBSCO and ISI.