Epigenetic modifications are the cause for the disease developments, environmental exposure, drug treatment and aging. Epigenetic changes can be reversible and are potentially targeted by the pharmacological intervention. Epigenetic changes are the factors of human diseases, including Fragile X syndrome, Angelman’s syndrome, Prader-Willi syndrome, and various cancers. About 80% of brain disorders are related to multiple genomic defects in conjunction with environmental factors and epigenetic phenomena.The significant role of epigenetics in brain development and disease is due to the several factors like plasticity of epigenetics during all periods of brain development and aging as well as dynamic regulation in neurons.

Cancer epigenetics is consider as the study of actual heritable changes to molecular processes which influence the flow of information between the DNA of cancer cells and their gene expression patterns. This includes comparison between tumor cell and normal cell and investigation of nuclear organization, DNA methylation, histone modification and the consequences of genetic mutations in genes encoding epigenetic regulators. DNA methylation patterns undergo complex changes in cancer. Many medicines which having a epigenetic impact are now used in several of diseases like cancer.

Behavioral epigenetics is referring to the study the role of epigenetics in shaping animal and human behavior. It is an observational science that explores that how the nurture shapes the biological heredity, where nurture refers to virtually all things that occur during the life-span like social-experience, diet and nutrition, and exposure to toxins. Behavioral epigenetics is giving a structure to know about how the expression of genes is altered by experiences and environment for forming the differences in behavior, cognition, personality, and mental health of everyone.

Epigenetic and transgenerational epigenetic inheritance research are performed on a multiple number of mammal, insect, and plant. A lack of research into these topics using farm animal models (bovine, porcine, ovine, and gallus) exists. Research into epigenetic transgenerational inheritance is limited because much of the work has focused on the direct effects of environmental submission to toxicants and nutrients. Pesticides are the cause of having dramatic transgenerational epigenetic effects on many of the animal models which affecting the nervous system, reproductive and endocrine systems, and even causing cancer. Changes in the epigenome induced by the environment have been documented in diverse animal phyla, ranging from insects to rodents to humans.

Plants are mainly depending on epigenetic processes for their proper functions. Plant epigenomes are more susceptible to environmental influence than those in animals. Epigenetic mechanisms are required for proper regulation while epi-alleles and epi-mutants, much like their genetic complements, describe changes in phenotype associated with distinct epigenetic circumstance. The study of epigenetics in plants is scientifically enthusiasm because epigenetics have long-standing importance in agriculture.

Cytogenetics is defined as the study of chromosomal structure, chromosome location and function in cells. Modern cytogenetic approaches are enable to precisely label the chromosomal location of any gene using different colored dots, examine cells from any type of tissue (even tumor cells), identify cells that have lost or gained a specific chromosome and determine whether specific regions of chromosomes have been lost or gained without ever looking at the chromosomes under a microscope.

A chromosome is a DNA molecule in which either part or all of the genetic material is present. The condensation of chromatin is used to form the chromosome. Chromatin structure depends on several factors. The overall structure depends on the stage of the cell cycle. Human chromosomes can be divided into two type’s autosomes and allosome.

Medical Epigenetics provides a comprehensive study of the importance of epigenetics to health management. Medical epigenetics is focusing on human systems, epigenetic diseases and treatments based on epigenetics-disorders and diseases. Medical epigenetics will cover all human systems relevant to epigenetic maladies. After the collection of genomic information and related data such as the levels of RNA, proteins and various metabolites that are crucial factors in medical, the genomic or personalized medicines are given to patients.

Epigenetic therapy is meant to use the drugs or epigenome-influencing techniques to treat medical states. Histone deactylases (HDACs), which modify histones, and DNA methyltransferases (DNMTs), which methylate DNA are the two enzymes that are important in epigenetic modifications and key targets for therapy with pharmaceutical drugs. Successful clinical studies carried out for both the enzymes. Epigenetic therapy has shown a strong effectiveness against hematological malignancies and solid tumors, gaining FDA approval for cutaneous T-cell lymphoma, ER-positive metastatic breast cancer, myelodysplastic syndrome, multiple myeloma, and peripheral T-cell lymphoma. Epigenetic therapy has proven successful for several types of cancer, including lung cancer, breast cancer, and lymphoma.

Epigenetics in the nervous system is the study of the interaction between epigenetic process, which regulates gene expression without changing the deoxyribonucleic acid sequence, and the development, physiology and functions of the nervous system.

Many of the computational, mathematical and statistical methods, ranging from data mining, sequence analysis, molecular interactions, to complex system-level simulations, have been reported in the literature. Efforts have been channeled into the text mining of epigenetic information, though development in this field is still at an early stage.

The study of epigenetic modifications on the genetic material of a cell is known as the epigenome. The field is parallel to genomics and proteomics, which are the study of the genome and proteome of a cell. Epigenomic maintenance (continuous process) is having an important role in maintaining the stability of eukaryotic genomes by taking part in crucial biological mechanisms. The plant flavones are the inhibiting epigenomic marks that cause cancers.

Epigenetic changes have a large number of effects on the aging process. At various levels these epigenetic changes occur, including decreasing the levels of the core histones, changes in the patterns of histone post-translational modifications and DNA methylation, substitution of canonical histones with histone variants and changes the noncoding RNA expression (during both organismal aging and replicative senescence). The reversible nature of epigenetic information provides exciting path for therapeutic intervention in aging and age-associated diseases, including cancer.

Transgenerational epigenetic inheritance is the transfer of information in organisms from parents to child that affects the characteristics of future generation without altering of the primary structure of DNA that is epigenetically. The term "epigenetic inheritance" may be used to describe information transfer in both the between cell and cell or organism and organism in organisms. Although in unicellular organisms these two levels of epigenetic inheritance are equivalent, they may have distinct mechanisms and evolutionary distinctions in multicellular organisms.

As per the current excitement of field of genomics, we can easily forget that genes are simply small sections of DNA and part of much larger structures known as chromosomes.

Epigenetic mechanisms of pathological process have been implicated in several Central nervous system diseases, containing neurodevelopmental disorders of cognition where interruption in learning and memory are the primary clinical abnormality. Cognition generally refers to the mental processes comprising the gain of knowledge and the ability to comprehend the same. There are about 86 billion neurons in the human brain, which are from sets of large and small scale synaptic networks. These networks form structures that function as networks for learning and cognition.

Occasionally in genetic studies or in plant breeding there is advantage in manipulating no single genes but large arrays of associated genes. Such arrays may consist of all of the genes in a set of chromosomes, or on a single chromosome, or on a segment of chromosome.

Epigenetics methylation refers to the addition of a methyl group (CH3) to the base cytosine (C) using covalently bond in the dinucleotide 5´-CpG-3´. Mostly the CpG dinucleotides in the human genome are methylated and the unmethylated CpGs are not distributed randomly, but are usually clumped together in ‘CpG islands, which are in the -region that facilitates transcription of a particular gene.

Genome compaction is one the universal feature of cells which has emerged as a global regulator of gene expression. Compaction is maintained by multiple numbers of architectural proteins, long non-coding RNAs (lncRNAs), and regulatory DNA.