唾液會出賣你的年齡
Saliva contains many useful components. Lubricants. Enzymes for breaking down food. And now, compounds that can reveal a person's age. That's according to a study in the journal Public Library of Science ONE. [Sven Bocklandt et al., "Epigenetic Predictor of Age"]
唾液中含有很多有用的化學成分。比如用來降解食物的潤滑劑、酶等。而剛剛發現，唾液中還含有能揭示人體年齡的化學成分。這個結論來自于《公共科學圖書館·綜合》期刊的一項研究。
During normal development, DNA in your body gets what's called methylated. Small chemicals called methyl groups bind to the DNA, helping to determine which genes become active. But the patterns of methylation change as we grow older. Which was a clue that measuring methylation might give away age.
在正常情況下，人體中的DNA會被甲基化。甲基基團會和DNA結合，幫助確認哪個基因要被激活。但是甲基化的類型會隨著人的年齡而改變。這樣就提供了一個思路：通過測量甲基化情況或許能揭示年齡的大小。
The researchers studied DNA in saliva contributed by 34 pairs of male identical twins, ages 21 to 55. They found 88 sites on the men's DNA where the amount of methylation correlated with their ages. The scientists next verified that finding in 60 men and women, ages 18 to 70.
研究人員對34對年齡在21到55歲的男性雙胞胎所提供的唾液樣品里的DNA進行了研究。他們發現男性DNA上88個位點的甲基化程度會隨著他們的年齡而變化。科學家之后又在60位年齡在18歲到70歲的男性和女性身上證實了這點。
Then they narrowed in on two genes that had the strongest age-related correlation. And using just that data, they found that they could estimate the ages of their saliva contributors to within five years.
隨后，他們將研究范圍縮窄至兩個與年齡密切相關的基因上。他們發現只用這些數據，就能夠估算出唾液提供者的年齡，誤差在5歲之內。
This technique might help in crime scene investigations-recovered saliva could tell the age of a perpetrator. So if you're worried about anyone knowing how old you are, be careful where you spit.
這項技術可能有助于犯罪現場調查--獲取的唾液能揭示犯罪嫌疑人的年齡。所以，如果你擔心有人知道你的年齡，吐唾沫的時候可要小心咯。
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