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More people are diagnosed with skin cancer in the US than any other cancer combined.
在美国，人们被诊断出患有皮肤癌的几率比其他任何癌症加起来都要高。
In fact, melanoma--a highly dangerous type of skin cancer--is estimated to claim one life every hour.
事实上，据估计，黑色素瘤——一种高危皮肤癌——每小时都会夺去一条生命。
So what if you could lower your risk of skin cancer by changing the color of your skin?
那么，如果你可以通过改变皮肤的颜色降低自己患皮肤癌的几率会怎样？
Ok, this is a big subject, so let's start with the science.
好吧，这个问题有点大，所以我们还是从科学依据开始说起吧。
Everyone has something in their skin called melanin, a biological pigment that gives us the color of our skin, hair, and eyes.
每个人的皮肤里都有一种叫作“黑色素”的东西，正是这种生物色素赋予了我们皮肤、头发和眼睛的颜色。
The cells in our epidermis that make this pigment are called melanocytes,
人体的表皮中产生这种色素的细胞叫做黑色素细胞，
and everyone has the same number of them,
而不同种族的人的黑色素细胞个数都是相同的，
but everyone's melanocytes make different amounts of melanin, and different kinds.
但每个人的黑色素细胞产生的黑色素的量不同，种类也不同。
Melanin serves a few very important purposes besides giving your skin its color.
除了赋予皮肤颜色外，黑色素还有几个非常重要的作用。
When you're outside, your skin is being exposed to the ultraviolet rays of the sun.
比如，当你在室外的时候，你的皮肤会暴露在太阳的紫外线下。
UV radiation is just that radiation and prolonged exposure can damage the DNA of your skin cells.
紫外线辐射就是那种辐射，长时间的暴晒就会损害我们皮肤细胞的DNA。
With enough damage, that DNA can start to malfunction and the life cycle of your skin cells is disrupted,
当损伤到了一定程度，DNA就会开始失灵，皮肤细胞的生命周期就会被打乱，
potentially causing uncontrolled replication and leading to cancerous growths.
就可能导致细胞的复制失去控制，进而导致细胞的癌变。
Your body's lookin' out for you though,
不过，我们还有身体的保护，
and has a couple of defense mechanisms in place--one of which is your melanocytes.
我们的身体有着随时准备就位的防御机制——其中一种机制就是黑色素细胞。
Inside your melanocytes are little melanin-producing factories called melanosomes.
黑色素细胞内有一些小的黑色素制造工厂，叫做黑素小体。
If the mitochondria is the powerhouse of the cell, the melanosome is the powerhouse of the melanocyte.
如果说线粒体是细胞的马达，那么黑素小体就是黑素细胞的马达。
And there are two kinds of melanin produced by these melanosomes--eumelanin, a darker pigment, and pheomelanin, a light-colored pigment.
这些黑素小体会产生两种黑色素——真黑色素，一种颜色较深的色素，和类黑色素，一种颜色较浅的色素。
Eumelanin blocks UV photons from damaging the skin,
真黑色素能阻止紫外线光子对皮肤的伤害，
so those without a lot of it--people with lighter skin--are at higher risk of sun damage.
所以那些皮肤内缺乏大量真黑色素的人——也就是皮肤颜色较浅的人——会更容易受到阳光的伤害。
So when your skin is exposed to more sun,
总而言之，你暴露在太阳下的皮肤面积越大，
your melanocytes are ‘turned on' to produce more of this UV-blocking melanin to protect your cells.
你的黑色素细胞“启动”后产生的这种阻挡紫外线，保护细胞的黑色素就越多。
How much melanin--and which kind--your skin makes is controlled by your genes.
你的皮肤产生多少黑色素——以及哪种黑色素——是由你的基因决定的。
That's why some people's skin tone deepens--or is making more melanin--when exposed to sunlight.
这也是为什么有些人在晒过太阳以后皮肤颜色会变深——或者说会产生更多黑色素的原因。
Others can't produce more than a certain amount of melanin, and so find their skin exposed to more damage, resulting in sunburn!
而其他人产生的黑色素则无法突破一定的量，他们的皮肤受到的伤害就会更大，最后就会导致晒伤！
So, more melanin equals darker skin tone and equals more protection from the sun's harmful rays.
由此可见，更多的黑色素就等于更黑的肤色，也就等于更大程度地保护皮肤免受太阳有害射线的伤害。
The big takeaway from all this detail is that those with more melanin, particularly eumelanin, are at decreased risk for skin cancer.
所有这些细节归结起来得出的一个重要结论就是，那些黑色素较多的人，尤其是真黑色素较多的人，患皮肤癌的风险会更低。
And now, researchers have explored how that level of protection can be artificially induced for those who don't have it naturally.
现在，研究人员已经开始探索如何人为地为那些无法自然获得这种程度的保护的人提供这样保护。
It turns out that the melanosomes that produce the two different types of melanin have different pHs,
事实证明，产生两种不同类型黑色素的黑素小体具有不同的ph值，
and remember the melanosome is that little pigment making machine inside your melanocytes.
记住，黑素小体是黑色素细胞内的色素制造机器。
Eumelanin, the dark, highly protective pigment, is produced by melanosomes that are less acidic than the melanosomes that produce pheomelanin.
真黑色素，就是那种颜色更深，保护能力更大的色素，是由比产生类黑色素的黑素小体酸性更弱的黑素小体产生的。
So researchers have posited--and now shown--that they can actually change the relative amounts of which kind of melanin your melanosomes produce.
因此，研究人员就假设——但现在已经证明了——他们实际上能够改变黑素小体产生的黑色素的相对数量。
Inhibiting a certain enzyme, called sAC, can make melanosome pH less acidic and allows those cells to produce more eumelanin,
抑制一种叫做sAC的酶，可以降低黑素小体pH值的酸性，允许这些细胞产生更多的真黑色素——
meaning darker pigmentation and increased protection from skin cancer.
这就意味着较深的色素沉淀和保护皮肤远离皮肤癌的能力的提升。
We're still not exactly sure why pH influences what kind of melanin your melanosomes produce,
虽然我们仍然无法确定为什么pH值会影响黑素小体产生何种黑色素，
and this is an area that researchers are hoping to explore further.
研究人员们也希望能进一步探索这一领域。
It's important to note that this is different from regulating melanin production by changing the way your genes are expressed, it's not genetic editing.
需要注意的是，这种手段和通过改变基因的表达方式来调节黑色素的产生是不一样的，这不是基因编辑。
This new research could instead result in a pharmaceutical drug that induces pigment production-
这项新研究可能促成某种能够诱导色素生成的药物的研发，
potentially for use by populations vulnerable to skin cancer, or those with pigmentation conditions that they'd like to treat.
或许能就此造福于易患皮肤癌的人群，或者那些有色素沉淀问题但可能因此得到治疗的人群。
This is still in the very early stages though, being tested in mice and human skin cells in petri dishes.
尽管这方面的研究目前仍处于非常初级的阶段，因为目前还在对小鼠和皮氏培养皿环境下的人类皮肤细胞进行测试。
It's a long way away from practical applications in humans.
距离真正应用到人体身上还有很长的路要走。
Ok, so the science is super cool.
也就是说呢，这方面的科学设想是非常酷的。
But the color of someone's skin has been something that defines and often divides humans for millennia.
只是，几千年来，皮肤的颜色一直是定义和区分人与人的标志。
So if it becomes possible for us to change that color in a very fundamental way for medical purposes,
那么，如果我们真的有机会出于医学目的从根本上改变我们的肤色的话，
what does that mean for our conception of things like race?
这对“种族”之类的概念意味着什么呢?
Would its use be ethical?
这种应用又是否符合人伦呢？
The authors of the study note at the very top of their research that skin pigmentation has not only health implications,
该项研究的作者在研究的一开头就已经指出，皮肤的颜色不仅事关健康，
but also very important psychosocial ones
也有着十分重要的社会心理学含义，
a reminder that science doesn't happen in a vacuum
因为它提醒着我们科学并非是发生在真空里的，
and its results and takeaways go out into an imperfect world
其结果和要义都是会走向我们这个并不完美的社会的，
and that's something we need to consider.
这点是值得我们考虑的。
What do you think about this research?
小伙伴儿们，你们觉得这项研究怎么样?
Let us know in the comments below, and keep coming back to Seeker for all things science news.
请在下面的评论中告诉我们，并记得回来观看我们栏目的更多视频噢。
And, fun fact! The scientific word for sunburn is erythema solare.
有意思的是，晒伤的科学术语是“日晒性皮炎”。
Thanks for watching.
感谢大家的收看。
