2025年12月四级第3套仔细阅读 Passage 2 原文翻译及答案解析

Genetic tests are being used for a growing number of purposes, from diagnosing diseases to finding out about our ancestors. But how accurate are these tests? And what does accuracy even mean in this context? There are important things to understand about genetic testing accuracy.

基因测试的用途日益广泛，从诊断疾病到追溯祖先。但这些测试有多准确？在这个上下文中，准确性又意味着什么？关于基因测试的准确性，有一些重要事项需要理解。

The accuracy of a genetic test depends on the specific question being asked and how complex the genetics behind a trait are. For relatively simple genetic conditions where a single gene is responsible, tests tend to be quite reliable. For example, tests for conditions like cystic fibrosis (囊性纤维化) or sickle cell disease (镰状细胞病) are generally very accurate because we understand the genetic basis of these diseases well.

基因测试的准确性取决于所问的具体问题以及性状背后的遗传学复杂性。对于相对简单的遗传条件，即由单个基因负责的情况，测试往往相当可靠。例如，对于囊性纤维化或镰状细胞病等疾病的测试通常非常准确，因为我们很好地理解了这些疾病的遗传基础。

However, for most common diseases, the picture is more complicated. Conditions like heart disease, diabetes, and most cancers are influenced by hundreds of genes, each contributing a small amount of risk. They are also affected by environmental factors and lifestyle choices. For these multi-factorial conditions, genetic health tests can only identify a fraction of the potential disease risk on their own.

然而，对于大多数常见疾病，情况更为复杂。像心脏病、糖尿病和大多数癌症等疾病受到数百个基因的影响，每个基因贡献一小部分风险。它们还受环境因素和生活方式选择的影响。对于这些多因素疾病，基因健康测试本身只能识别一小部分潜在疾病风险。

What makes genetic tests for multi-factorial traits particularly tricky to interpret is the interaction between genes. Even if we know that hundreds of genes are involved in a trait, predicting how those genes will interact with each other is extremely difficult. The combined effect of multiple genes is not simply the sum of their individual effects.

使多因素性状的基因测试特别难以解释的是基因之间的相互作用。即使我们知道数百个基因参与了一个性状，预测这些基因将如何相互作用极其困难。多个基因的综合效应并非仅仅是它们各自效应的总和。

Some companies also offer DNA tests that claim to predict personality traits, athletic ability, or even help you find a romantic partner. At present, using DNA to predict such complex traits does not have a solid scientific basis. The genetics behind personality and talents involve thousands of genes and complex environmental interactions, making any predictions essentially meaningless with current technology.

一些公司还提供DNA测试，声称可以预测性格特征、运动能力，甚至帮助你找到浪漫伴侣。目前，使用DNA预测如此复杂的性状没有坚实的科学基础。性格和才能背后的遗传学涉及数千个基因和复杂的环境相互作用，使得任何预测在当前技术下本质上都毫无意义。