two hours wasn’t long enough.”
As Kinrais walked away, Vanessa leaned back down to the kid, “Okay,” she said brightly, “what would you like to do now?”
The kid’s eyes narrowed a little as if he were regarding her suspiciously, then he said, “Can you show me around the lab first? I’ve never even seen a culture plate. I’d like to see your incubators, autoclaves, bioreactors, laminar flow cabinets, centrifuges, chromatographs, DNA sequencers, PCR equipment, microarray readers, and anything else you use frequently. Reading about this equipment hasn’t really given me any feel for what it’s actually like.”
Vanessa’s eyes had widened during this recitation. Now her own eyes narrowed as she studied the child. Can he really be three years old? ‘Cause if he is, “precocious” doesn’t even begin to describe how freaky he is! After a second she smiled at him, stood up, and said, “Sure! Let’s start down on this end.”
The kid climbed up on stools to peer into, over, and around each of the pieces of equipment. She offered him a culture plate and had him touch it with his fingers, telling him he could take it home and see the bacterial colonies that formed from his touch by the next day. The questions he asked, though, were almost scary. He knew the names of many of the common species of microorganisms found in the intestine and wanted to know what she thought would happen if the balance of the microbiota shifted one way or another.
He seemed especially interested in Dr. Turner’s research on the effects of gut microflora on mouse obesity. The kid might only be three years old, but he knew what Turner’s papers said better than she did. “So what do you think? Does changing the microflora make people gain or lose weight? Or do you think that eating the kind of food that makes you fat changes the microflora?”
Vanessa studied him while she considered her answer.
Evidently the kid thought that she wasn’t just “thinking,” because he said, “Yeah, I’m fat. And I’m wondering if I’m fat because of the bacteria in my gut, not just because I eat too much. I don’t think that’s a crime.”
Vanessa managed not to wince at how close the kid had come to some of the thoughts that had passed through her consciousness. Instead of admitting her guilt, she lied by saying, “Oh no, I wasn’t thinking about your weight. It’s just that you asked a very difficult question.” She shrugged, “It’s a really hard question to answer in people because they don’t follow diets very well. We know from mice that are raised germ free—so that they don’t have any microflora in their intestines—that if we then populate their gut with bacteria they rapidly gain a lot of weight. The general belief is that the organisms in your intestines help you harvest more energy from your food so that you can gain weight. We also know that if we put bacteria from obese mice into the guts of these germ-free mice that they don’t just gain weight up towards normal, they become obese. This suggests that the bacteria in the intestines do have a significant effect on obesity.”
The kid frowned at her, “So what about in people?”
“When we study people, we find that obese people have different microflora in their intestines than people of normal weight. But if we put obese people on a diet, assuming they follow it, their microflora changes from what it was when they ate whatever they wanted.” She shrugged, “So, it’s really hard to tell which is cause, and which is effect.”
After a moment in which the boy seemed to be thinking, he said, “So if you wanted to find out what kind of bacteria were growing in someone’s intestines, you’d have to do a culture of their stool?”
“Well, we don’t have to do a culture anymore. DNA microarrays will identify most of the microorganisms and give us a good idea of their prevalence. It’s actually much more accurate than a culture. But if we do a