P.C. Shannon

Recently I was watching the ST:TNG episode “Genesis“. The science in this episode is all on the level of the Heisenberg compensator, which is to say, laughably bad. (Someone did point out once that a Heisenberg compensator doesn’t necessarily mean one can determine both a particle’s speed and position, it just compensates for the fact that you can’t.) But Dr. Crusher’s estimation of the number of genes in the human genome was pretty accurate, at least for 1994.

Estimations of the number of genes make for an amusing measure of scientific progress. I’ve heard that in the 60’s, the number was estimated in the millions. According to Star Trek, it was down to 100,000 by the mid-nineties. (It’s also interesting to note that at that time, the Human Genome Project would have been considered to be only a third of the way into it’s fifteen year lifespan, but it actually finished in 2001, four years ahead of schedule, because the technology improved so drastically during the project.) I noticed recently that my genetics textbook, which was probably written in 2001, estimates the genome to be between 40,000 and 60,000. The current estimate is much more like 27,000.

For comparison’s sake, the fruit fly Drosophila melanogaster has about 12,000 genes. The bacterium E. coli, which is famous for killing people at Jack in the Box but also thrives in your intestines, has about 3000 genes.

We’re far more than twice as complex as a fruit fly, or nine times as complex as a lowly bacterium. Clearly there are other mechanisms that contribute to complexity, so that it doesn’t scale linearly with gene number. We already know about several, but we’re also finding new ones.

The picture is somewhat more complicated because the idea of a gene has changed over time, and, in my opinion, is fairly nebulous. The word “gene” actually has two different meanings, even in the halls of science. In one sense, it means “allele.” Alleles are different types (or flavors) of one gene. So when someone says, “he has the gene for sickle cell anemia,” they really mean he has the allele for it. The average person has the non-sickle cell allele.

The other meaning is “locus,” which is the physical position of the gene in the genome. You might hear, for example, that the gene for color blindness is on the X-chromosome, which really means that the locus is there.

When we talk about how many genes there are in the genome, we’re really talking about loci and not alleles. Some of the recent discoveries about gene regulation—the mechanisms that make us so much more complex than fruit flies even though we only have about twice as many genes—turn traditional notions about these mechanisms on their ear. They may even require another revision to the number of genes in the human genome.

I'm amazed at how the brain works. For instance, there's a word that I've been trying to remember for the better part of a year. I'll want to use it in a conversation, because it perfectly captures what I want to say, but I can't, because I can never remember it. This word means “that which is directly observed” and is frequently used in high school discussions of the scientific method (which makes this problem all the more embarassing). I've actually come across it once or twice in this quest, but I can't seem to hang on to it. I keep thinking it is or is similar to “epistemological” because the first sound is the same and they both have to do with knowledge.

How can I know that? How can I know what a word means and what it sounds like but not know the word itself? It's really quite amazing.

I looked the word up before I started writing this, but now I've forgotten it again. Which leads me to my real conclusion: I'm just getting old.

That word, by the way, is “empirical.”

I first noticed this phenomenon with the rise of shows like Battle Bots. The combatants on that program are sophisticated remote controlled vehicles, not robots. A robot is an automaton. The word itself, with all of the sci-fi implications behind it, is sexy, and that’s why they use it.

I was watching a program — Science Times, I think — yesterday on The National Geographic channel, and they had a segment on “rat bots.” These are rats that have had three electrodes inserted into their brains that allow them to be lead around remotely, sort of the high-tech equivalent of dangling a piece of cheese. The idea is that you can get them easily into a building that has collapsed or been taken over by terrorists. The segment also featured competing technology in the form of remote controlled vehicles, referred to on the program as robots.

Netiher the rats nor the “robots” are autonomous. Both require a remote operator to guide them to their destination. Roomba, the robot vaccuum cleaner, is a real robot because you turn it on and without any further input from you, it will clean your room. It is autonomous. Imagine what a crappy product it would be if you had to sit at your computer and guide it around the room.

Eventually we will have real robots that can search for survivors in the aftermath of an earthquake wihtout direct control by a person out of harms way. The current crop of search-and-rescue robots are a good place to start. They’re just not actually robots.