Multi-omics and male infertility: status, integration and future prospects.

Within the cell, gene expression analysis is the key to gain information about  different cellular and physiological events. The multifaceted route of fertilization is a combination of different processes, which include production, maturation and ejaculation of the sperm, its travel through the female genital tract, followed by the ultimate fusion of the fertile sperm with the egg. Early embryogenesis and gametogenesis as well as gene expression at tissue level and global gene silencing are under different levels of stringent epigenetic checks. Moreover, transcriptome (expressed segment of the genome in form of RNA) and the proteome (expressed set of genomic proteins) contribute uniformly to the overall cellular gene expression. In both normal and pathophysiological environments, this gene expression is altered across various levels viz., genome variations, post-transcriptional modifications, protein expression and post translational modifications. Consequently, more informative conclusions can be drawn through a new 'omics' approach of system biology, which takes into account all the genomics, epigenomics, proteomics, and metabolomics findings under one roof, thus computing the alterations in all the entities (genes, proteins, metabolites) concurrently.