科技。

　　Social status and health.

　　社会地位与健康。

　　Misery index.

　　贫困指数。

　　Low social status is bad for your health. Biologists are starting to understand why.

　　社会地位低对身体不好，生物学家开始理解此中的奥秘。

　　ONCE upon a time the overstressed executive bellowing orders into a telephone, cancelling meetings, staying late at the office and dying of a heart attack was a stereotype of modernity. That was before the Whitehall studies, a series of investigations of British civil servants begun in the 1960s. These studies found that the truth is precisely the opposite. Those at the top of the pecking order actually have the least stressful and most healthy lives. Cardiac arrest-and, indeed, early death from any cause-is the prerogative of underlings.

　　曾今，人们对现代化的一个根深蒂固的印象是，领导们在巨大压力的折磨之下，对着电话狂吼，下达命令，取消会议，待在办公室到很晚，最后死于心脏病。可是，自1960年代开始的英国白厅对英国政治家们展开的一系列调查之后，这种印象开始改变，因为调查发现事实却完全不是那么回事。实际上处于社会高层的人们承受的压力最小，生活最健康。心跳骤停——而且，确实是，不管是出于什么原因的早死——那都是做下属的才有的事。

　　Such results have since been confirmed many times, both in human societies and in other primate species with strong social hierarchies. But whereas the pattern is well-understood, the biological mechanisms underlying it are not. A study just published in the Proceedings of the National Academy of Sciences, however, sheds some light on the matter.

　　在人类社会，还有等级严格的其他的灵长类物种中，都已多次验证这种结果的正确性。但是，虽然这种模式很容易理解，潜在的生物学机制却并不这么认为。杂志《国家科学院》最新出版的专题里，对此现象有相关阐述。

　　In it, a group of researchers led by Jenny Tung and Yoav Gilad at the University of Chicago looked at the effects of status on rhesus macaques. Experience has shown that these monkeys display the simian equivalent of the Whitehall studies' findings. The high risk of disease among those at the bottom of the heap in both cases suggests that biochemical responses to low status affect a creature's immune system. Those responses must, in turn, depend on changes in the way the creatures' genes are expressed. To investigate this phenomenon means manipulating social hierarchies, but that would be hard (and probably unethical) if it were done to human beings. You can, however, do it to monkeys, and the researchers did.

　　专题里，詹妮东和要吉拉德领导的研究小组在芝加哥大学，研究地位之于恒河猴的影响。实验经过表明，这些猴子所表现出来的是英国白厅研究发现的猴子版本。社会地位低的患病风险高，这既适用于人类界也同样适用于猴子。这暗示了社会地位低的物种的生物化学反应影响其免疫系统。反过来，这种生物化学反应又取决于物种生物基因的变化方式。若要调查这种现象，那就意味着需要控制社会等级，在人类身上进行，很困难（而且很可能不道德）。但是，你可以在猴子身上做实验，而且研究人员也是这么做的。

　　Unhappy minds in unhealthy bodies.

　　不健康的身体，不快乐的心情。

　　Dr Tung and Dr Gilad took 49 middle-ranking female macaques (females were chosen because a lot of previous work on animal hierarchies has been done on female macaques) and split them into groups of four or five. The researchers were able to control where in a group an individual ranked by the order in which it was introduced into its group (newly introduced monkeys almost always adopt a role subordinate to existing group members). The hierarchies thus established, the team conducted tests on cells in the monkeys' blood, in an attempt to determine the effect of a macaque's rank on her biochemistry and, in particular, on how rank influences the activity of various genes.

　　博士东和吉拉德，用49个中等地位等级的女性猴子做实验（用女性猴子的原因是，前期大量动物地位等级的准备工作都是在女性猴子身上做的），并把他们分为四到五组。根据猴子们加入研究群体的时间顺序，研究人员给她们的地位等级编号（新来的都是要听前辈的，这是潜规则）。等级于是得以建立。研究团队采集猴子血液做细胞研究，试图搞清楚恒河猴的地位等级对其生物化学的影响，特别是地位等级是如何对各种基因活动起作用的。

　　The answer is, a lot. Dr Tung and Dr Gilad looked at the expression in each animal of 6,097 genes (30% of the total number in a monkey genome-or, for that matter, in a human one). They were searching for correlations between social rank and gene activity, and in 987 genes they found one. Some genes were more active in high-ranking individuals; others were more active in low-ranking ones. The relationship was robust enough to work the other way round, too. Given a blood sample and no other information, it was possible to predict an individual's status within her group with an accuracy of 80%.

　　研究结果有很多。每个动物有6097个基因，博士东和吉拉德观察每个动物的基因（一个猴子基因组总数的30%??——这也适用于人类），寻找社会等级与基因活动之间的相互关系。在987个基因中，他们找到了一个。某些基因在等级高的个体中更活跃，而其他的基因则活跃于等级低的个体中。这一结果很牢靠，倒过来看也成立。只提供血液样本而没有其他相关信息，就可以预测个体在群体里的地位等级，且精确度达到80%。

　　The next question was what all these genes actually do. Sure enough the answer, for a substantial fraction of them, was that they regulate aspects of the immune system. In particular, low-status individuals showed high levels of activity in genes associated with the production of various immune-related cells and chemical signalling factors, as well as those to do with inflammation (a general immune response that involves tissue swelling and increased immune-cell activity in the affected area). Although the researchers did not explicitly examine the health of their simian charges, chronic, generalised inflammation is a risk factor, in people, for a long list of ailments ranging from heart trouble to Alzheimer's disease.

　　下一个问题，所有这些基因，真正起的是什么作用。答案很显然，对大部分基因而言，它们起着调节着免疫系统的作用。这非常明显地体现在，社会地位低的个体，产生各种与免疫相关的细胞和化学信号基因的活动更为明显，还有那些有关于炎症的基因（一种普通的免疫反应，包括细胞组织的膨胀，还有增加免疫细胞在疫区免疫细胞活动）。虽然研究人员没有仔细分析参与实验的猴子们的健康状况，但是慢性的、全身性的炎症对猴子们来说是危险因素，人类的部分，就是从心脏病到老年痴呆症等一大长系列疾病。

　　Finally, the team investigated the mechanisms behind these differences in gene expression. In keeping with previous work, they found that high- and low-rank individuals showed different levels of responsiveness to a class of hormones called glucocorticoids, which regulate immune-system activity and response to stress. They also found changes in the mix of cells within the animals' immune system itself. But what is new, and intriguing, is that they discovered, for the first time, evidence that a phenomenon called epigenetic change is at work.

　　最后，研究小组用基因表达调查造成这些不同的机理原因。与之前工作结果一致，他们发现地位高和地位低的个体，对被称为糖皮质激素的一组基因，表现出的反应级别不一样。糖皮质激素控制免疫系统活动和对压力的反应。同时他们发现，在动物免疫系统自身，混合细胞有发生改变。但是最为新奇的是，他们头一次发现了后天改变在起作用的证据。

　　Epigenetics—currently one of molecular biology's hottest topics—is a process by which genes are activated or deactivated by the presence or absence of chemical structures called methyl and acetyl groups. Dr Tung and Dr Gilad found that methylation patterns were systematically different in high- and low-ranking animals. Crucially, these changes are generally passed on to the daughter cells produced when a cell divides, and are thus perpetuated throughout an animal's life. To the extent that epigenetic marking is involved in creating social status, then, status may be being maintained by the animal's cells as they replicate.

　　表现遗传学——目前分子生物学最热的话题之一——是这样一个过程，基因的激活或是失效取决于被称为甲基和乙酰基的化学结构的存在或是消失。博士东和吉拉德发现甲基模式在地位高级和地位低级的动物之间是不一样的，且这种不一样是系统性的不一样。至关重要的一点是，这些变化一般在细胞分裂的同时传递给子细胞，因此这些变化将贯穿动物的一生。从此意义上讲，后天标记参与社会地位的形成，社会地位的维持靠动物细胞的复制。

　　Destiny's child?

　　命运的产物？

　　Those who believe in progress will, however, be pleased to know that epigenetics is not necessarily destiny. Methyl groups may help maintain the status quo, but if that status quo is interrupted by outside events they can be wiped away and a new lot put in place.

　　但是，相信事物是发展变化的人们会很高兴，因为表现遗传学并不是上天注定，难以改变的。甲基或许可以帮助维持现状，但是如果外来事件打断了它，那么甲基将被移除，新的一批上任。

　　Dr Tung and Dr Gilad discovered this because a few of their monkeys did change status within their groups. When that happened, changes in gene expression appropriate to the new status quickly followed. Those who do break free from their lowly station, then, may begin to reap the health benefits almost immediately.

　　博士东和吉拉德能够发现了这一点，是因为，参与实验的几个猴子确实改变了她们在群体中的地位等级。地位等级一旦发生改变，与之相应的基因表达随即改变。那些确实改变了它们之前卑贱地位的猴子们，身体状况几乎都立刻获得改善。

　　As with any animal study, this one cannot simply be mapped straight onto humans. But it does provide pointers that researchers who work on people can use. In particular, the experiment ensured that social rank was the only factor being changed, providing strong evidence that the chain of causality runs from low social status, through a disrupted immune system to worse health, and not the other way around. The best medicine, then, is promotion. Prosper, and live long.

　　不管以什么动物为研究对象，结果都不能直接简单地运用于人类，这个也不例外。但它确实给研究人类的学者们提供了一些建议。该实验的独特之处是，它确保了实验中社会等级是唯一发生改变的因素。它为因果关系链的正确模式提供了一个强有力的证据，正确模式是低等的社会等级通过被破坏了的免疫系统损害健康。而不是反过来的顺序。晋升是疗效最好的药物。因为成功，所以活得长久。