Hologenome$ , [Holo Greek, from holos, whole;] a term borrowed from evolutionary biology is defined as the sum of the genetic information of an organism, or in rather words, the organism and its microbiota. The Hologenome thus signifies a mixed population of genomes. Hologenomics deals with the genomics of a hologenome of mixed populations of genomes, as in the case of interacting populations in host-pathogen and commensals. Hologenome differs from the widely popular term Metagenome, which involves the study of communities of microbes directly in their natural environments.
The availability of next-generation sequencing (NGS) technology has enabled the scale and ease of addressing biological questions on a genomics perspective. The throughput of sequencing enables deep sequencing of nucleic acids, adequate to provide for enough reads of the pathogen, even while the interference of the host genetic material is very high. Metagenomics has been one of the major applications of NGS technology for understanding the composition and dynamics of mixed population of organisms.
-Footnotes$This definition of hologenome is not entirely in sync with the definition as proposed by Rosenberg and Rosenberg (Zilber-Rosenberg I, Rosenberg E FEMS Microbiol Rev 2008, 32:723-735) which limits the definition to microbial symbionts, but conceptually similar and encompasing a whole range of other possibilities including microbial pathogens.
Genomics of Infectious Diseases Lecture at Christian Medical College Ludhiana on 6th March 2021