Two weeks ago I wrote about mutant biology in a way I thought was clarifying. However, in a way not uncommon for science, explanation yielded as many questions as answers, which is great! There’s nothing a scientifically inclined person enjoys more than having another avenue of inquiry to explore, so let’s do just that!
I think the biggest issue with my previous article was that I didn’t get nitpicky enough, guess that makes me a bad comic book fan. I talked about the how mutants are a subspecies of Homo sapiens, but then talked about how different species are formed. Well what’s the difference between a species and a subspecies?
The answer is actually kind of fuzzy and gray, which is commonly the case in ecology and evolutionary biology. Evolution is complex and messy, so cut and dry answers tend to be few and far between. I found that most people learning these concepts were dissatisfied by that reality when I had to teach it to students anxious about a test, so I will reassure you now: there is no test, we’re just speculating for fun.
To define a subspecies we’ll have to remember how we defined species. In my previous article I defined a species using the Biological Species Concept (BSC) stating that a species is a group of interbreeding or potentially interbreeding organisms that produce viable fertile offspring. So a subspecies is defined as two groups within a species that fit all those criteria, but aren’t mating with each other for some other reason. Like if the mutants had their own country or island keeping them isolated from humanity.
After doing a little research (aka I called my buddy Jesse, who is an X-Men nerd) I was actually able to find some evidence supporting the subspecies not separate species hypothesis. My contention before was that mutants should be a separate species if hybrids of human and mutant were sterile. The example I keep going back to is the Scarlet Witch and Quicksilver (human mother, mutant father). For the most part, we don’t know if mutants are fertile (defined as capable of having offspring) even though Brian K. Vaughn mentions fertility issues for mutants in Runaways. But Jesse reminded me that Quicksilver did in fact have a kid with the Inhuman Crystal. I actually had known they were married but didn’t realize about the kid, named Luna and pictured at the right. At first I resisted the idea because Crystal is hardly a baseline Homo sapien sapien (which begs the question of what species an Inhuman would be? Maybe they’re like mules and just have a genus). But Jesse was able to convince me that the criterion is simply “Can Quicksilve produce children” and it shouldn’t matter if he does so with a human or anything else.
This means that mutants are more properly classified as a subspecies and not a separate species, but the only thing a subspecies needs to become a new species is time, space and a reproductive isolating mechanism (potential subject for yet another column, I'll never run out).
This brings me to the next question from the comments of the previous article, are all mutants themselves the same species? This is also a bit tricky but if we say that a mutant is defined as a person with a genotype containing the X-gene then they should be classified as a mutant. How the X-gene expresses itself (aka it’s phenotype) can still vary from individual to individual, as we all know, some variation within a species is normal. However, I think the broad classes of powers like telepaths, bestial types, elementals could be classified as breeds or races (although both those terms are kind of loaded) because breeds or races are just groups within the same species that are so similar they don’t even count as subspecies.
Why then do some parents pass on similar powers to their offspring and not others? I think that comes down to some environmental stochasticity. The way some genes express is affected by the environment. It can lead to a bit of extra randomness within what the gene does. So perhaps the X-gene in an individual has a few possible powers that could manifest, and whichever power is the most relevant in the stressful moment of express is the one that becomes active. This could explain why Cyclops and Havok have slightly different but very similar powers.
That being said, I think certain power sets would tend to dominate the population given enough time because of their inherent usefulness in many different situations. Wolverine can heal very fast and will live for a long time; it makes sense that his kids would develop those powers; just as Rachel Summers is better served by telepathy than energy projection (or the X-gene from the X chromosome of the mother is more dominant).
I think it’s totally possible that if mutants only mated with other mutants within a few generations there’d be nothing but telepaths and fast-healers, even ignoring the associated image. But I guess I won’t elaborate on that further in case Marvel asks me for a pitch.
At the end of the day, the Marvel mutants were not created with sound genetics in mind. I know this, obviously, but like many columns I write the fun is trying to see how real science could possibly fit within these fantastic stories. And I have no problem just accepting that the rules for genetics and speciation in 616 might be a little bit different than here. If anything it means there will always be another column waiting to be written about the whacky science behind mutants. What about hybrid vigor? Are some mutants reproductively isolated due to their powers? Are bald telepaths more powerful? In the meantime, give me some more fodder to work with in the comments!