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Transgenerational epigenetic inheritance is the transmittance of information from one generation of an organism to the next (e.g., parent–child transmittance) that affects the traits of offspring without alteration of the primary structure of DNA (i.e., the sequence of nucleotides). The less precise term "epigenetic inheritance" may be used to describe both cell–cell and organism–organism information transfer. Although these two levels of epigenetic inheritance are equivalent in unicellular organisms, they may have distinct mechanisms and evolutionary distinctions in multicellular organisms. Four general categories of epigenetic modification are known:〔Jablonka E and MJ Lamb (2010). Transgenerational epigenetic inheritance. In: M Pigliucci and GB Müller Evolution, the expanded synthesis〕 # self-sustaining metabolic loops, in which a mRNA or protein product of a gene stimulates transcription of the gene; e.g. ''Wor1'' gene in ''Candida albicans'' # structural templating in which structures are replicated using a template or scaffold structure on the parent; e.g. the orientation and architecture of cytoskeletal structures, cilia and flagella, prions, proteins that replicate by changing the structure of normal proteins to match their own # chromatin marks, in which methyl or acetyl groups bind to DNA nucleotides or histones thereby altering gene expression patterns; e.g. ''Lcyc'' gene in ''Linaria vulgaris'' described below # RNA silencing, in which small RNA strands interfere (RNAi) with the transcription of DNA or translation of mRNA; known only from a few studies, mostly in ''Caenorhabditis elegans'' For some epigenetically influenced traits, the epigenetic marks can be induced by the environment〔 and some marks are heritable,〔 leading some to view epigenetics as a relaxation of the rejection of soft inheritance of acquired characteristics.〔 == Major controversies in the history of inheritance == Humans have recognized that traits of the parents are often seen in offspring. This insight led to the practical application of selective breeding of plants and animals, eventually leading to domestication, but did not address the central question of inheritance: how are these traits conserved between generations, and what causes variation? 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Transgenerational epigenetic inheritance」の詳細全文を読む スポンサード リンク
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