This chapter’s going to address mutation, and also to reply to the question raised by Tears of Crimson, and, earlier, by Another Rogue. But before I get into all that, I’ll answer some of the scattered smaller points in the reviews.

First, WarugiKaiu made an excellent point—technically, the theory of evolution only addresses changes in existing organisms. Therefore, it is possible to believe in Creation and evolution, if you’re flexible with your beliefs. The only problem here, of course, is the age of the world. Radioactive dating, geological and astronomical evidence, and the fossil record all point to an Earth that is billions of years old. I say that it’s tough to argue that carbon dating, geology, astronomy, and paleontology are all completely wrong. I suppose there’s another way out of this for the enterprising Creationist, a nice little logical twist that I find absolutely delightful, and which has no technical flaws. I’ve heard some arguments for “God created the universe already made.” I say, hey, sure. If you’re an omnipotent being, and you want to whip up some dinosaur bones, I say more power to you. And if you’re omniscient, I know you aren’t going to screw up. It’d be completely within the Judeo-Christian God’s power to create a pre-aged universe. And there’d be no way to test it, right or wrong. Heck, God could’ve set up the universe yesterday, and just slapped a whole bunch of wacky memories into your head. So believe away.

Second, as for the beginning of life—there are a number of lovely scientific hypotheses for this, all substantiated by some preliminary evidence. Nothing’s set in stone yet, but there’ve been tests demonstrating the creation of DNA chunks and self-replicating proteins using only the basic materials present in the baby Earth’s primordial atmosphere, with a lightning strike as a catalyst. So go for God if you’d like, but science is working on it.

Third, g21lto has two little comments. The first is that evolution takes a really long time. Damn straight. Evolution took billions of years to turn single-celled organisms into multi-celled organisms. (That’s American billions, by the way.) After the invention of sex, evolution sped up like a uranium racecar with square wheels powered by Shetland ponies—it now only took mere millions of years to grow an extra stomach.

G21lto also asked if my fish-to-frog example in the previous chapter was just a thought experiment, or if it’s supported by actual evidence. The answer is yes, it’s been substantiated by the fossil record and by numerous evolutionary biologists.

Now that’s taken care of, on to...

Mutation: Not Just for X-Men Anymore

Okay, reviewers. Some of you have wondered about mutation—how can random changes in DNA change an organism without killing it outright? Both Tears of Crimson and Another Rogue brought up the various ‘mutations’ we’re familiar with—most of them fatal in the first few hours of life.

But those aren’t all. Many mutations do nothing to change the fitness of an organism, and some even help it out—so first I’ll explain how mutation works.

Every creature has DNA. These long molecules encode all the information that makes our bodies our bodies—hair color, how much we grow, our build, our brains, everything. Every cell of our bodies has an exact copy.

Ah. What’s this I say? Copy. Are there microscopic fax machines running around in our innards? Well, yeah, pretty much. There are a fleet of special enzymes whose job is solely to replicate DNA strands, to make new cells, including gametes—those are cells with a randomly-determined half of your DNA which can combine with a special, lucky someone else’s gametes to produce babies. I’ll explain this process in more detail later, and how it helps evolution so much.

So there are little things in your body that copy DNA. Your body is like a computer—everything is documented and everything has a purpose, even the spleen. Everything ticks along like clockwork—but things are always screwing up. Nobody’s body is ever 100 on any given day. So naturally, those DNA-copiers mess up. And actually, they mess up a lot. So all of your cells have the exact same DNA. Pretty much. And those sperm (or eggs) floating around in your innards? They could have traits you’ve never even thought of.

See, DNA strands are packed with information. But still, for all that, they’re full of blank space, ‘filler’ space which are marked as useless and, as far as scientists can tell, have no effect on an organism. This stuff gets mixed up all the time. And if a copy-enzyme accidentally includes some of this “junk DNA” in with the real genes, things change.

“So things change,” you say. “But mutations are almost always fatal or debilitating, right?”

Not necessarily. Imagine ‘color’ genes—hair, eyes, skin. What if those get mixed? All that happens is your skin, hair, and irises get a bit of a dye job in the womb. And for an animal that might want camouflage, that can be a life-saver. There are lots of genes—thousands of genes—that can get flipped and mixed and jumbled with little ill effect on the finished product.

How about some examples?

Albino animals are sometimes caused by mutations. There are mutations all the time in the populations of disease-carrying bacteria that thwart our attempts to cure influenza. You can’t find a more successful organism than the flu virus! See, mutations in the really important genes are often destructive, but much of the other stuff really doesn’t matter.

Want a great one? Calico cats. You know why they’re always female? Because they have to be to secure a third X chromosome! The fur-color gene’s on the X, and so the extra one interferes in spots all over the body, making those tell-tale patches. Crazy, huh? All from a mistake during gamete formation.

Mutations are constant and omnipresent. Some are good, some are bad, some do nothing. But they change the gene pool, sometimes introducing things that mere gene-trading and natural selection would never have come up with. For billions of years before sexual reproduction, mutation was the only game in town.

Guess what the next chapter’s about.