Distribution of core biological functions conserved in Halobacterium sp. NRC-1 and four other halophiles. Core biological functions shared between H. sp. NRC-1 and each halophile were classified into twelve classes and the number of genes in each category is plotted. Most of the functions are conserved with respect to H. sp. NRC-1. Mechanisms common to halophiles, such as active ion transporter system to maintain osmotic balances in and outside of the cells and DNA repair mechanism in response to possible UV – irradiation, seem well preserved.