Figure 2 Published 26 May, 2015 at 598 × 358 in Identification of the positively selected genes governing host-pathogen arm race in Vibrio sp. through comparative genomics approach Figure 2. Classification of Orthologous genes according to COG category. NCBI COG database was used to identify the COG category of every gene included as orthologous. All of the Vibrio cholerae genes were fallen into eighteen categories.