Listen to a conversation between a student and his biology professor.
Hi, Dennis! You're right on time. Come on in and have a seat.
So, like I told you in class, I just wanted to take a few minutes to meet with everyone, to make sure your class presentations for next week are all in order and coming along well.
And as you know, you're supposed to report on some area of recent research in genetics-something, you know…original.
Well,I think I've found just the thing.
It actually occurred to me a couple nights ago, while I was eating dinner in the cafeteria…
Tell me, Professor…do you like broccoli?
[taken aback] Broccoli? You mean, the vegetable broccoli?
[hesitantly] Well… I guess, not really…
Me neither. I've never liked it-or most other vegetables, for that matter: brussels sprouts, asparagus, cauliflower-you name it.
They just taste bitter and…well,nasty to me. My mother always called me a picky eater.
[wondering where this might be leading] O-kayyy…and?
And so I got to wondering… I mean, I’m obviously not the only person like this.
So is this just because of some, like, trauma from our childhoods-some bad experience we've had with vegetables- or could there be some genetic explanation for why some people are picky eaters and others aren't?
[catching on now] OK, I see. Well, I suppose it’s a possibility…
Actually, it turns out it's more than a possibility.
I started doing some research in the library that night. And I found out that a biologist at the National Institutes of Health has been looking at that very question recently.
Well, I guess that's not too surprising-and this is great stuff, actually! So what's the verdict?
Well, this guy seems to have discovered a particular gene that actually makes it possible for people to taste the bitterness in certain green vegetables!
But people who have a mutation in that gene cannot taste the bitterness.
[mulling it over] Well, that’s…certainly fascinating…
But…so this biologist is basically claiming that people who like to eat these vegetables actually have some sort of sensory deficit?
[humorously] Sorta makes us picky eaters the normal ones, doesn’t it? I mean, that's kinda turning things on their head, isn't it?
[matter-of-factly, not snidely] Well, then again, it wouldn’t be the first time, would it? Think of it this way…
Humans originally needed to have a stronger sensitivity to bitter-tasting foods, so they could learn what plants were good for them and which ones might be poisonous.
But at some point, as people figured out what they could safely eat, this need became less crucial,and a segment of the population lost that ability.
OK,well-you make a compelling case! I can't wait to hear more about this when you deliver your report.