Letter From The Editor - Issue 69 - June 2019

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  Science Fact-ion by Randall Hayes
October 2016

I've Got a Mathy Model by this Russian Guy at NIMBios

I'm very well acquainted, too, with matters mathematical,
I understand equations, both the simple and quadratical,
About binomial theorem I'm teeming with a lot o' news,
With many cheerful facts about the square of the hypotenuse.
I'm very good at integral and differential calculus;
I know the scientific names of beings animalculous:

-Gilbert & Sullivan, “The Modern Major General”

I live in North Carolina, where the small-government legislature has (with no apparent irony) decided to regulate where people go to the bathroom, supposedly to prevent cross-dressing sexual predators from molesting unguarded females. Clearly, this has more to do with scaring people to the polls than it does with actually preventing any real abuse, since relatives and “family friends” molest so many more children than strangers do. Here we have an example of a classic finding from psychology, that humans under-react to common dangers and over-react to uncommon ones.

Science fiction has likewise traditionally focused on the taboo aspects of human or alien sexual behavior. Up through the 1980s, it was mostly involved in reinforcing those taboos by having bad things happen to people who violated them, although there was also some gentle, usually humorous, tweaking. Starting in the 1950s, though, with Philip Jose Farmer's “The Lovers,” and building since then, there's been a consistent effort by some SF authors to break all of those taboos. This debate is still reverberating through fandom, to the extent that our former editor felt it necessary to turn down a Hugo nomination because he didn't agree with the fans who nominated him.

I was trained as a biologist before I got into neuroscience as a specialty, and biologists approach sex in a different way. As best we can, we simply describe how living things act, without inserting our personal feelings. We measure, and we count, and we experiment. Sometimes we use the data we have collected to build mathematical models to try and explain or predict the actions of living things. In a few paragraphs I'll describe one of those models to you. But first, a quick tour.

The first purpose of sex was not reproduction, per se. By that statement, I mean that reproduction does not necessarily require sex. The majority of Earth's species, which are single cells, can get along perfectly well through simply cloning themselves. They do this so quickly and so often that they don't really care about fatal mistakes, which remove themselves from the population. Minor mistakes (mutations) are the source of the genetic diversity microbes use to adapt to Earth's constantly changing environment. Some are so efficient they can divide in as little as 20 minutes. It's a perfect strategy for simple creatures.

Unfortunately, if your body (and the genome that it carries in every cell) is larger and more complicated, it takes longer to copy it. Although being big is an advantage in terms of individuals eating and being eaten, this slower reproduction is a serious liability in evolutionary terms, because the microbes don't wait; they just keep dividing and evolving. Some of those microbes can trade individual genes or small chunks of their genomes, making them even more adaptable, but sex allows for large-scale shuffling of the entire genetic deck every generation. Thus generations can be longer, and bodies have time to grow larger and more complicated. The microbes are still a danger, but they can be held at bay.

As soon as this system of gene shuffling was firmly in place several hundred million years ago, we started fiddling with it. Many plants and fungi, and lots of the earliest animals, were both male and female, capable of trading genes with any neighbor they came across, or in some cases with themselves if nobody else was around. Later creatures started to specialize in being either male or female, though that was pretty flexible, and there are still many species of fish that switch gender like the people from Ursula LeGuin's The Left Hand of Darkness or Greg Egan's “Oceanic.”

Now, “fiddling” is probably too friendly a term. If a system exists, it can be hacked for personal advantage—to get more out of a sexual transaction, in terms of genetic offspring, than one puts into it, in terms of time and energy, which biologists call parental investment. The story of evolution is one long dynamic, shifting compromise between cooperation and competition, the study of which biologists call game theory. Both cooperation and competition are enhanced by communication. The form of the communication doesn't matter. Chemical signals, sounds, and visual display behaviors can all be hacked during honest competition, or dishonest cooperation, or any other combination. If you can imagine it, some species probably beat you to it.

What does any of this have to do with HB2 and human behavior, or the behavior of aliens? Well, I promised you a mathematical model, and it's time to deliver. Sergey Gavrilets at the University of Tennessee has written an elegant paper on testosterone signaling inside the developing fetus. Testosterone is an ancient steroid hormone that acts directly on the genome, turning on genes that males use and turning off genes that females use. Technically, male and female are distinctions that don't even make sense at the genome level, but we'll continue to use the labels for the sake of convenience. That's right; the shuffling process (as it exists on Earth) requires that you, as a male, have female genes so that you can pass them along to your daughters, and vice versa. Turning those unused genes off involves a process of attaching chemical tags to the DNA during development, as the gendered body is being built, and of stripping them off again in the gonads during meiosis, which is the biologist's polite word for making sperm or eggs.

Your body is complicated, with many different organs, including all those tiny brain regions, which have to be separately regulated by the same hormone (testosterone) circulating in the blood. Gavrilets proposes separate brain regions for gender identity and sexual attraction, among many other traits that you'd expect to be testosterone-sensitive (like parenting, for instance, or aggression—especially aggression). Differently tagged genes in different regions could respond differently to exactly the same level of testosterone, with no changes to the genetic sequences themselves. Gavrilets doesn't know where those circuits might be, but for a mathematical model he doesn't need to know. He just places them into his model and assigns numbers to them for parameters like how many cells in those circuits have their DNA chemically tagged, and thus how sensitive to testosterone they are. He can generate a surprising amount of behavioral diversity without affecting secondary sex characteristics like body size or hairiness or whatever.

This is a cool idea because science has been searching for “gay genes” for decades, and hasn't found them, which has left the culture in another endless and useless Nature vs. Nurture debate. Some people want “gay genes” because they believe that if we find them, gay people can't be blamed for a biological trait, as opposed to a personal lifestyle choice. This paper, as well as the entire history of the X-Men, suggests this is a vain hope; humans can blame one another for anything. Other people want “gay genes” because they hope to “cure” transgender body issues, or homosexuality, or whatever. These are issues SF has played with in a loose metaphorical fashion for a long time, but adding specifics as Gavrilets has done (whether he's right or not) makes your story more concrete. You can propose new ways to hack the system, real or fictional, and the debate moves to a new level, beyond simple scare tactics, maybe all the way to figuring out—as a society—what we actually want, and how to get there.

Randall Hayes presents as male—genetically, behaviorally and fashionably (right down to his naturally bushy eyebrows)—but he does own the entire George Perez run on Wonder Woman. In between watching episodes of The Gilmore Girls he runs Agnosia Media, LLC and recruits speakers for the Greensboro Science Cafe.













Scroll down not just for this story, but for any of Mr. Egan’s other freely available work.



Shoot me again! I enjoy it! I love the smell of burnt feathers, and gun powder, and cordite! I'm an elk! Shoot me, go on! It's elk season! I'm a fiddler crab! Why don't you shoot me? It's fiddler crab season!”









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