Evolution of genome organization and epigenetic machineries

Abstract

The unit content of DNA in a living organism containing all of its genes is referred to as ‘genome’, which forms the basis of life and heredity. In the path of evolution from a single-cellular prokaryotic life to multi-cellular eukaryotic system, the genome has become more and more complex not only in the context of size but also in sequence and content. Although the size of the genome does not directly correlate with the complexity and hierarchy of a living organism, in the eukaryotic system with restricted nuclear size, disproportionately higher size of DNA is packed into a highly ordered manner (Kumari et al., in Kundu (eds) Epigenetics: development and disease. Subcellular biochemistry, Springer, Dordrecht, 2013). This packaging of genome with the assistance of protein and RNA is not a unique feature of the eukaryotic system alone. In fact, even in a tiny prokaryotic cell, to reduce the volume and to restrict the signal dependent availability of the genomic material (DNA), packing of genome is essential. In this brief article, we shall try to put forward a concept of genome organization and epigenetic machineries to assist the functional ability of the genomic material in the evolutionary perspective.