2018医学考博英语阅读理解文章精析：社会地位与身心健康

　　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).

　　博士东和吉拉德，用 49 个中等地位等级的女性猴子做实验，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。

　　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.

　　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.

　　研究结果有很多。

　　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.

　　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，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。

　　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%.

　　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.

　　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。

　　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).

　　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。

　　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.

　　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.

　　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。

　　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.

　　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.

　　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。

　　Dr Tung and Dr Gilad found that methylation patterns were systematically different in high- and low-ranking animals.

　　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。

　　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.

　　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。

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