The Taboo of Sympatic Speciation

My critique partner Leslie Dicken and her alter ego Jordanna Kay were recently interviewed by the Gotta Write Network. I even got a mention in the article as well for designing the cover of Taboo.

Taboo cover Taboo is the story of two societies who have lived apart on a remote planet for generations: the Aerotaun and the Marimar. The Aerotaun are a people who have built wings to help them fly; the Marimar are hearty swimmers who live and feed by the sea.

And now my inner science nerd wants to come out to play. Both Leslie’s story Taboo and my Silent Elegiac deal with the concept in Evolution called speciation.. If I understand the concept correctly, Taboo is an example of allopatric speciation:

During allopatric speciation, a population splits into two geographically isolated allopatric populations (for example, by habitat fragmentation due to geographical change such as mountain building or social change such as emigration).

I’ve read conflicting information as to whether with allopatric speciation the two populations in question can interbreed. The ability of coyotes and dogs to interbreed (“coydogs“) and the recent discovery of introgression between homo sapiens and homo neandertalis seem to indicate that interbreeding is possible.

Taboo demonstrates two populations that were once one, existing under separate but heavy environmental pressures. Initially, the parent population is stranded on a planet where they inhabit an existing structure that had been abandoned by a previous indigenous culture. I don’t know if Leslie intended it, but I had the Anasazi loosely in mind when I read the story. The structure itself is enormous and part of it has collapsed acting as a barrier between the two populations.

Silent Elegiac, on the other hand, is an example of a single population consisting of a subset with a genetic polymorphism (mutation), and so it may be an example of sympatic speciation where:

. . . homozygous individuals may, under particular environmental conditions, have a greater fitness than those with alleles heterozygous for a certain trait. Under the mechanism of natural selection, therefore, homozygosity would be favoured over heterozygosity, eventually leading to speciation.

In Silent Elegiac, the polymorphic population has enhanced hearing, specifically absolute pitch and a high ability to mimic sounds. This subgroup are called Minstrels. From their perspective, the “normal” part of the population, who they call the Avarecchio, are considered to possess “miser’s ears.” I think the two populations in this story are an example of sympatric speciation because the separation emerged from a genetic mutation that resulted in initial reproductive isolation while living side-by-side. The two populations eventually separated geographically, intensifying the differences. The heroine of the story, Auren, is from the Minstrel population and is homozygote for the trait, while the hero is at first thought to be an Avarecchio, but is in actuality heterozygote for the mutation and a latent Minstrel.

Both stories explore what happens when the two populations cross back together. Can they learn to live together or will they remain separate? What knowledge does each population have about their shared origins and their possible futures? What happens when people ignore established taboos?

Despite sharing scientific underpinnings, Taboo and Silent Elegiac are very different stories. Taboo explores the friction between sky-based and sea-based cultures and the secrets kept by both, while Silent Elegiac explores music-color synesthesia, the perception of reality, and the fate of people who challenge the absurdity of some social customs. I hope you enjoy both stories.