ディーゼル排気微粒子のDNA変異原性・遺伝子傷害性の研究である。わずか２時間の暴露で遺伝子のスイッチON/OFFが簡単に起こるらしい。大気粒子に含まれる多環芳香族炭化水素（PAH）類に起因するDNAのメチル化であろう。
DNAのメチル化は不必要な遺伝情報を隠したり出したり。DNAのメチル化および脱メチル化はこれまで考えられてきた以上にダイナミックにはたらいていると予想され。DNAのメチル化はDNAの配列の変化を伴わないで、メチル化されたDNAが子孫に伝達されたり修飾が除かれたりする（epigeneticsエピジェネチックス）。
タバコの煙も危険ではある。
昔の話ではあるがある博士論文審査会で偉い先生から
”君、メチル化ごときで何が変わるというのだ？”
と質問されたことがある。先生、水とメタノールの違いはどうでしょうか？と返答したかったが止めたことがある。
Methylation is one of several mechanisms for controlling gene expression, which is the focus of a rapidly growing field of study called epigenetics.
という。
Breathing in diesel exhaust leads to
changes 'deep under the hood'
Date:January 8, 2015
Source:University of British Columbia
Summary:Diesel exhaust switches some genes on, while switching others off, by altering the methylation of DNA, scientists say.
sciencedaily.com
Just two hours of exposure to diesel exhaust fumes can lead to fundamental health-related changes in biology by switching some genes on, while switching others off, according to researchers at the University of British Columbia and Vancouver Coastal Health.
The study involved putting volunteers in a polycarbonate-enclosed booth -- about the size of a standard bathroom -- while breathing in diluted and aged exhaust fumes that are about equal to the air quality along a Beijing highway, or a busy port in British Columbia.
The researchers examined how such exposure affected the chemical "coating" that attaches to many parts of a person's DNA.
That carbon-hydrogen coating, called methylation, can silence or dampen a gene, preventing it from producing a protein -- sometimes to a person's benefit, sometimes not.
Methylation is one of several mechanisms for controlling gene expression, which is the focus of a rapidly growing field of study called epigenetics.
図
scienceblogs.com/pharyngula/2008/07/22/epigenetics/
scienceblogs.com/pharyngula/2008/07/22/epigenetics/
The study, published this month in Particle and Fibre Toxicology, found that diesel exhaust caused changes in methylation at about 2,800 different points on people's DNA, affecting about 400 genes.
In some places it led to more methylation; in more cases, it decreased methylation.
How these changes in gene expression translate to health is the next step for researchers. But this study shows how vulnerable our genetic machinery can be to air pollution, and that changes are taking place even if there are no obvious symptoms.
"Usually when we look at the effects of air pollution, we measure things that are clinically obvious -- air flow, blood pressure, heart rhythm,"
said senior author Dr. Chris Carlsten, an associate professor in the Division of Respiratory Medicine.
"But asthma, higher blood pressure or arrhythmia might just be the gradual accumulation of epigenetic changes. So we've revealed a window into how these long-term problems arise. We're looking at changes 'deep under the hood.'"
The fact that DNA methylation was affected after only two hours of exposure has positive implications, said Carlsten, the AstraZeneca Chair in Occupational and Environmental Lung Disease.
"Any time you can show something happens that quickly, it means you can probably reverse it -- either through a therapy, a change in environment, or even diet,"
he said.
Carlsten's team, having catalogued the changes along the entire human genome, is now sharing its data with scientists who are further exploring the function of specific genes.
Nutrition and the Epigenome
learn.genetics.utah.edu/content/epigenetics/nutrition/
Unlike behavior or stress, diet is one of the more easily studied, and therefore better understood, environmental factors in epigenetic change.
The nutrients we extract from food enter metabolic pathways where they are manipulated, modified, and molded into molecules the body can use. One such pathway is responsible for making methyl groups - important epigenetic tags that silence genes.
Familiar nutrients like folic acid, B vitamins, and SAM-e (S-Adenosyl methionine, a popular over-the-counter supplement) are key components of this methyl-making pathway.
Diets high in these methyl-donating nutrients can rapidly alter gene expression, especially during early development when the epigenome is first being established.
atdbio.com/content/56/Epigenetics