你知道嗎? 我們超過一半的身體不是人類!

More than half of your body is not human, say scientists.
科學家們稱，人身體裏超過一半的組成“不是人類”。

Human cells make up only 43% of the body's total cell count. The rest are microscopic colonists.
人體只有43%的細胞屬於人類，而其他的部分則是由非人類的微生物細胞羣組成。

Understanding this hidden half of ourselves -- our microbiome -- is rapidly transforming understanding of diseases from allergy to Parkinson's.
理解關於我們的隱藏的一半，即我們的微生物羣，正在迅速轉變人們對過敏和帕金森病的認識。

The field is even asking questions of what it means to be "human" and is leading to new innovative treatments as a result.
該領域甚至提出了“人類”意味着什麼的問題，並導致了新的創新療法。

"They are essential to your health," says Prof Ruth Ley, the director of the department of microbiome science at the Max Planck Institute, "your body isn't just you".
馬克斯普朗克研究所微生物羣系科學部主管魯斯·萊教授稱：“它們對你的健康至關重要，你的身體不僅僅是你的。”

No matter how well you wash, nearly every nook and cranny of your body is covered in microscopic creatures.
無論你把自己洗得多幹淨，在你的身體幾乎每個角落和縫隙中，仍然都生長着微生物。

This includes bacteria, viruses, fungi and archaea (organisms originally misclassified as bacteria). The greatest concentration of this microscopic life is in the dark murky depths of our oxygen-deprived bowels.
這些微生物包括細菌、病毒、真菌和古細菌（最初被誤分類爲細菌的生物體）。這種微生命最集中的地方是我們黑暗渾濁的、缺氧的腸道的深處。

Prof Rob Knight, from University of California San Diego, told the BBC: "You're more microbe than you are human."
加州大學聖地亞哥分校的羅布·奈特教授向BBC透露：“與其說你是人類，不如說你更多是微生物。”

Originally it was thought our cells were outnumbered 10 to one.
原先的認識是，我們人體中人類細胞的數量和微生物的比例超過了10比1。

"That's been refined much closer to one-to-one, so the current estimate is you're about 43% human if you're counting up all the cells," he says.
他說道：“這一數字已經更新爲接近一比一了，所以目前的估計是，如果你將所有的細胞計算在內，你大約有43%的部分是人類細胞。”

But genetically we're even more outgunned.
但從遺傳角度看，人類甚至要被甩得更遠。

The human genome -- the full set of genetic instructions for a human being -- is made up of 20,000 instructions called genes.
人類基因組--人類的全套基因指令--由20,000個稱爲基因的指令組成。

But add all the genes in our microbiome together and the figure comes out between two and 20 million microbial genes.
但如果把人體內所有微生物的基因數目加起來，這個數字將會達到200萬到2000萬之間。

Prof Sarkis Mazmanian, a microbiologist from Caltech, argues: "We don't have just one genome, the genes of our microbiome present essentially a second genome which augment the activity of our own.
加州理工學院的微生物學家薩爾基斯·馬茲曼尼亞教授認爲：“我們不只有一個基因組，我們微生物組的基因基本上是第二個基因組，它增加了我們自己的活動。”

"What makes us human is, in my opinion, the combination of our own DNA, plus the DNA of our gut microbes."
“在我看來，是什麼讓我們成爲了人類，就是我們自己的DNA和我們腸道內微生物DNA的結合。”