Pan-genomics: Unmasking the gene diversity hidden in the bacteria species

The dramatic increase in genome sequencing during the last years has changed our ideas about bacterial diversity, from single gene to whole community DNA surveys; we have learned that nature's lagest gene repository resides in bacteria resides in bacteria. Comparison of bacteria genomes has contributed to understand the flexibility in size and gene content as well as the gene movement due to gene family expansions and Horizontal Gene Transfer. Bacteria species are currently defined by means of 16S rRNA sequence comparisons and some limited phenotypic traits. There is an ongoing debate about the biological and evolutive significance of the bacteria species, and thus the need to refine the definition of it using the most of the genomic shared information across any taxonomic range. When comparing multiple genomes of related strains we can distinguish a set of common shared features which are known as the core genome. In the other hand, the set of strain specific genes are known as accessory genome. The accessory and core genome conform the total of the genetic composition, and are known as pan-genome. Here we present the possibilities using pan-genomics as a workhorse to describe both taxonomical and functional diversity within bacteria.