58-61The reductive evolution provides a pathogen minimal gene set. Due to loss of genes, for drug target identification, biochemical techniques cannot be used since these pathogens are difficult to culture. Besides classical drug targets i.e. toxins, adhesions, some novel drug targets, using a molecular phylogeny approach, can be identified. Horizontally transferred genes in bacterial pathogen from their eukaryotic host has been classified as ‘Novel drug target’, and a reusable system for identifying horizontally transferred gene has been built using a molecular phylogeny approach. Using this system, two genes have been identified in Mycobacterium leprae, which have also been identified by other methods