Epigenetic modifications and its basic mechanism

Abstract

Heritable changes in the plant's phenotype are attributed to genomic sequence change and also by epigenetic variations. These epigenetic variations are involved in controlling plants' developmental processes. Intense and close breeding has reduced the genetic variations in crop increasing their susceptibility to the changing environment. Epigenetic diversity has now emerged as a new source of variation for coping with changing environmental stresses in plants. Epigenetic modifications like DNA methylation, post-translational histone modifications, histone variants, and involvement of non-coding RNAs have played a major role in gene expression and regulation in plants. These epigenetic modifications have created the variability in phenotypic expression by selective turning on and turning off of the genomic sequence. These variabilities are created in plants in response to the environmental factors to which plants are exposed. These phenotypic variations accumulated by epigenetic modification are transferred and expressed in the next generation as they are heritable. DNA methylation and methylation of histone tails on the lysine 4, 9, and 27 positions are among the best-characterized epigenetic marks observed in both plants and animals. These modifications marks have altered the physical state of the DNA. The alternation in the physical state of DNA has changed the way cell reads the genes. This is the potential new area of the research as it creates phenotypic variability in response to stress factors without changing the chemical properties of the DNA. In this paper, we have presented the epigenetic modifications and the way they controlled the gene expression in plants and animals.