Int.J.Curr.Microbiol.App.Sci (2020) 9(5): 2961-2971 2961 Review Article https://doi.org/10.20546/ijcmas.2020.905.339 Epigenetics Mechanisms in Insects: A Review U. Pirithiraj 1 , R. P. Soundararajan 2 * and C. Gailce Leo Justin 1 1 Anbil Dharmalingam Agricultural College and Research Institute, Tiruchirappalli-620 027, India 2 Horticultural College and Research Institute (Women), Tiruchirappalli-620 027, India *Corresponding author ABSTRACT Introduction The growing population and degrading environment are two major problems at international level. Satisfying the growing population‘s requirement is somewhat difficult. Although there were legal and social constrains in utilizing the biotechnology researches in field level, these tools improve agriculture and human life to a great extent (Ahmad et al., 2012). Genetically modified mosquitoes created possibilities for controlling diseases like malaria (Catteruccia et al., 2003). In 1994, the ―flavr savr‖ (first GM tomato) was commercialized (Yang et al., 2005). Bt cotton was the first GM crop approved for use in India (Kapur et al., 2010). Almost in the entire living organism‘s gene-modification International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 9 Number 5 (2020) Journal homepage: http://www.ijcmas.com Epigenetics is the study of heritable changes in gene expression that do not involve changes in the underlying DNA sequence (or) a change in phenotype without a change in genotype. Phenotype is the observable or measurable characteristics of an organism i.e., height, behaviour, colour, shape, and size. Insects are being examined for their epigenetic phenomena and the underlying mechanism behind it. Epigenetics is well studied in fruit fly, Drosophila melanogaster. Gene is segments of the DNA sequence that store the information to synthesize proteins or RNAs that carry out specific functions. Epigenetics is important in cellular differentiation which is responsible for the phenotypic plasticity. Epigenetics is been investigated in plants and animals. On comparing other organisms insects possess a high degree of phenotypic variation. This variation is due to switch on and off mechanism of gene. Gene expression and repression in insects is regulated through epigenetic mechanisms i.e. DNA Methylation, Histone modification and Noncoding RNAs which influence the phenotypic modification. In recent days insects are used as models in studying epigenetics. RNA interference (RNAi), also known as RNA silencing, refers to a set of molecular processes in which noncoding RNA molecules target and silence the expression of specific nucleic acids. Silencing Dnmt3 expression in newly hatched honeybee larvae mimics the effect of royal jelly, namely, the larvae destined to become workers develop into queens with fully developed ovaries. The detailed mechanisms of epigenetics in insect were discussed in the paper. Keywords Epigenetics, Insects, DNA methylation, Histone modification and RNAi Accepted: 23 April 2020 Available Online: 10 May 2020 Article Info