Transgenerational Epigenetic Inheritance

Transgenerational epigenetic inheritance is the transfer of epigenetic markers from one organism to the next (from parent to child) that affects the traits of the offspring without changing the primary structure of DNA.

Environmental factors can induce epigenetic markings for some traits that are influenced epigenetically, while some markers can be inherited, leading some to believe that with epigenetics, modern biology no longer resists the relentless inheritance of acquired traits.

Categories

• Self-sustaining metabolic loops in which a protein product or mRNA of a gene stimulates the transcription of the gene.
• Structural templates, in which the structures are replicated onto the main structure using a template or scaffold structure.
• Chromatin tags in which methyl or acetyl groups bind to nucleotides or histones of DNA and thus change gene expression patterns.
• RNA silencing, in which small strands of RNA disrupt the DNA transcription or the mRNA translation.

Inheritance

In all the sexually reproducing organisms, much of the epigenetic modification within cells is reestablished during meiosis, although they have been shown to be preserved some epigenetic responses. The different inheritance of epigenetic traits due to the paternal biases or underlying maternal in the mechanisms of elimination or retention can lead to epigenetic causality being assigned to some originating effects in plants and animals.

In mammals, epigenetic marks are erased in two phases. On the one hand in the development of primordial germ cells and on the other hand shortly after fertilization. During fertilization, female and male gametes combine in different stages of the cell cycle and with different configurations of genome. The epigenetic traits of the male are quickly diluted. The protamines which are associated with male DNA are replaced by histones from the female cytoplasm, most of which are acetylated due to a higher frequency of acetylated histones in the female cytoplasm. Also male DNA is systematically demethylated in many organisms. However, some epigenetic traits, particularly maternal DNA methylation, can escape this reprogramming which then leads to a paternal imprint.