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July 24, 2013


Scientists Discover How Epigenetic Information Could Be Inherited: Mechanism of Epigenetic Reprogramming Revealed

Science Dailyより





New research reveals a potential way for how parents’ experiences could be passed to their offspring’s genes. The research was published today, 25 January, in the journal Science.


Epigenetics is a system that turns our genes on and off. The process works by chemical tags, known as epigenetic marks, attaching to DNA and telling a cell to either use or ignore a particular gene.


The most common epigenetic mark is a methyl group. When these groups fasten to DNA through a process called methylation they block the attachment of proteins which normally turn the genes on. As a result, the gene is turned off.


Scientists have witnessed epigenetic inheritance, the observation that offspring may inherit altered traits due to their parents’ past experiences. For example, historical incidences of famine have resulted in health effects on the children and grandchildren of individuals who had restricted diets, possibly because of inheritance of altered epigenetic marks caused by a restricted diet.


epigenetic inheritance エピジェネティック遺伝

However, it is thought that between each generation the epigenetic marks are erased in cells called primordial gene cells (PGC), the precursors to sperm and eggs. This ‘reprogramming’ allows all genes to be read afresh for each new person – leaving scientists to question how epigenetic inheritance could occur.


epigenetic inheritance エピジェネティック遺伝
primordial germ cell 始原生殖細胞
primordial gene cells 始原遺伝子細胞

The new Cambridge study initially discovered how the DNA methylation marks are erased in PGCs, a question that has been under intense investigation over the past ten years. The methylation marks are converted to hydroxymethylation which is then progressively diluted out as the cells divide. This process turns out to be remarkably efficient and seems to reset the genes for each new generation. Understanding the mechanism of epigenetic resetting could be exploited to deal with adult diseases linked with an accumulation of aberrant epigenetic marks, such as cancers, or in ‘rejuvenating’ aged cells.


hydroxymethylation ヒドロキシメチル化

However, the researchers, who were funded by the Wellcome Trust, also found that some rare methylation can ‘escape’ the reprogramming process and can thus be passed on to offspring – revealing how epigenetic inheritance could occur. This is important because aberrant methylation could accumulate at genes during a lifetime in response to environmental factors, such as chemical exposure or nutrition, and can cause abnormal use of genes, leading to disease. If these marks are then inherited by offspring, their genes could also be affected.


aberrant methylation 異常メチル化

Dr Jamie Hackett from the University of Cambridge, who led the research, said: “Our research demonstrates how genes could retain some memory of their past experiences, revealing that one of the big barriers to the theory of epigenetic inheritance – that epigenetic information is erased between generations – should be reassessed.”

研究を主導したケンブリッジ大学、博士ジェイミーハケットは述べました: "我々の研究は遺伝子が彼らの過去の経験の幾つかの記憶をどのようにして保持できたかを示して、エピジェネティクス情報が世代間で消去されるとのエピジェネティック遺伝の理論への大きな障壁の一つは再評価されるべきであることを明らかにした。“

“It seems that while the precursors to sperm and eggs are very effective in erasing most methylation marks, they are fallible and at a low frequency may allow some epigenetic information to be transmitted to subsequent generations. The inheritance of differential epigenetic information could potentially contribute to altered traits or disease susceptibility in offspring and future descendants.”



形質(けいしつ、trait, character)とは、生物のもつ性質や特徴のこと[1]。 遺伝によって子孫に伝えられる形質を特に遺伝形質と呼ぶが、単に形質と言えば遺伝形質のことを指すことが多い

Disease Susceptibility り病性; 罹病性

However, it is not yet clear what consequences, if any, epigenetic inheritance might have in humans. Further studies should give us a clearer understanding of the extent to which heritable traits can be derived from epigenetic inheritance, and not just from genes. That could have profound consequences for future generations."


heritable traits 遺伝形質

Professor Azim Surani from the University of Cambridge, principal investigator of the research, said: “The new study has the potential to be exploited in two distinct ways. First, the work could provide information on how to erase aberrant epigenetic marks that may underlie some diseases in adults. Second, the study provides opportunities to address whether germ cells can acquire new epigenetic marks through environmental or dietary influences on parents that may evade erasure and be transmitted to subsequent generations, with potentially undesirable consequences.”

ケンブリッジ大学、本研究の主任研究員、Azim Suran教授は述べた:“新研究は2つの異なる方法で役立てる可能性を有しています。第一に、本研究は幾つかの成人病の根底にあるかもしれない異常なエピジェネティック・マークを消去する方法についての情報を提供することができるだろう。第二に、本研究は生殖細胞が両親に影響する環境または食事の影響を通して、消去を逃れて次世代に遺伝子し、潜在的に望ましくない結果をもたらす新たなエピジェネティック・マーク取得できるかどうかを言及する機会を提供する。


*哺乳類初期発生における「エピジェネティック制御」の謎を解明! ―たった1つの受精卵から細胞が分化する神秘の解明に大きな貢献―大阪大学より








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