虽然我们经常认为“实验大鼠”和“豚鼠”是大部分实验的对象，但在实验室研究中最广泛流行的其实是不起眼的小鼠。小鼠之所以在实验室这么受欢迎也不是毫无道理，其中最主要的原因便是它们不仅廉价而且很容易繁殖。
But the researchers of the world aren't just choosing mice because they're a cheap date that you can buy in bulk. Consider that the mouse's DNA looks startlingly like ours; in fact, we share more than 90 percent of the same genes as a mouse [source: Koshland Science Museum]. This means that when it comes to the ways our molecules work, you're going to find that mice and people aren't all that different.
但是，科研人员并不仅仅是因为廉价才选择小鼠作为实验对象的。令人吃惊的是，小鼠的DNA看起来和我们人类的差不多。事实上，我们人类和小鼠的基因有90%是相同的。这也就意味着，当涉及到分子水平时，你会发现小鼠和我们人类并没有那么不同。
Now understand that there are animals that are even closer to us genetically: primates, dogs, pigs. (Yup, you and bacon are practically siblings.) But working with those animals presents more problems. Obviously, they're bigger and more difficult to house and feed. But they also present larger ethical problems that some people are more comfortable dismissing when it comes to our rodent pals. In other words, mice might not be the closest animals to us genetically, but they are one of the closest that we feel comfortable using in studies.
当然了，有些动物在基因上更接近人类，比如灵长类动物、狗以及猪。但是和这些动物一起工作会带来更多的问题：首先，这些动物的体型都比较大，更加难以饲养。另一方面，使用它们进行实验也存在更大的伦理问题。而涉及到我们的啮齿类动物伙伴时，有些人更愿意置之不理。换句话说，小鼠可能不是基因与我们最相近的动物，但在适合用于研究的动物中，小鼠的基因确实更接近人类。
How can studies on mice translate to humans? While we'd like to think that we'd never stoop to running a maze for a treat, the truth is that much of our underlying behavior isn't that different from the behavior of a mouse. There's a reason that tests that measure addiction, reward and learning are conducted on mice: They exhibit the same motivations that we do.
对小鼠的研究为何适用于人类?虽然我们人类决不会屈尊通过走迷宫来获得治愈，但事实是我们的大部分潜在行为与小鼠的行为并没有太大的不同。也就是说，在小鼠身上进行一些测试是有原因的：它们常常表现出和我们人类一样的动机。
The scope of mice-to-human studies is becoming even broader as we learn more about the mouse genome -- and how to manipulate it. Genetically engineered mice might sound like the stuff of horror films, but consider them a scientist's dream. "Knockout" mice are those that have been manipulated so a certain gene is turned off or inactivated; transgenic mice have foreign DNA incorporated into their genome [source: The Jackson Laboratory]. These kind of mice are an extraordinary resource for modeling human disease; for instance, research has found that mice that are genetically mutated to carry the BRCA1 gene (a human breast cancer gene) behave more similarly to human cancer patients than those mice who have had a tumor physically transplanted in. Also, knocking out the leptin gene in mice showed that this hormone regulated appetite. Now, leptin is used in treating some people who are obese .
随着人类对小鼠基因组的了解越来越多，小鼠对人类的研究也更加重要了。基因改造鼠听起来像是恐怖电影里的东西，但它们其实是一些科学家的梦想。例如，研究发现，携带人类乳腺癌基因的小鼠比那些只是移植了肿瘤细胞的小鼠表现得更像癌症病人。同时，在小鼠体内“敲除”掉瘦素基因也表明这种激素被用于调节食欲。现在，瘦素已经被用来治疗一些肥胖病人。
