SF, DNA, and pondering

[den]

Something level_head wrote got me thinking. Proteins. Are there other bases and base pairs besides Adenine, Guanine, Thymine and Cytocine? I expect there are but I don't know where to start looking for them.

I always wonder about this when I watch SF shows. The Heroes land on an alien planet, meet the natives, get invited to dinner and start stuffing food into their faces. Why should the carbohydrates twist the same way as their enzymes? Why should the proteins have the same bases? Why don't they get sick? The only way the Heroes wouldn't die of malnutrition is if God created all the worlds using the same basic DNA template. Assuming life on all worlds started from the same primordial soup random-act-of-bindness, the chances of two worlds having the exact same DNA would be astronomical. Even proteins with the same bases but a right-handed twist would make the stuff unusable as food for us.

In my stories each character's medical records are linked to the food services databases. How else would food synthsizers know what a character can and can't eat? Different body chemestry could mean something that is a coffee sweetener for one alien could be a narcotic for another, and instand death for a third.

If you find me shouting "WHY AREN'T YOU BEING SICK" at an SF show on the telly, it's probably dinner time for them.

Comments

[hafoc.livejournal.com]

Very good. :) I run into the same thing in my writings, although I gloss over it.

Why couldn't life exist on a world with air pressure much higher than ours? Or with, say, three times the carbon dioxide? Yet such conditions would probably kill us. If such minor differences could be fatal, even on worlds where everything else was ideal, how is it possible that alien species could happily live together on the same planet? Then throw in all the other possible variations-- left-handed vs. right-handed proteins, different proteins, different genetic materials than DNA-- and the odds that we could live with alien animals, let alone eat them, seems vanishingly small.

But that would throw away all my plot ideas, so I ignore it. :)

As for SF films, I've come to believe there's a great conspiricy involved. I suspect that all those aliens are actually humans only PRETENDING to be aliens, in search of financial gain. If that's the case it's no wonder they can eat the same food we do, 'cuz they is us.

:)

[dewhitton.livejournal.com]

Yeah. Sometimes those aliens look like they have a big wad of latex on their face. I don't think they're aliens at all.