Phylogeny of the elves illustrates why we need to sample elf DNA immediately

Maybe not sister taxa, but these are definitely members of the same clade.

Last year for Christmas Eve, Dominic Evangelista reconstructed the evolutionary history of elves and elf-like fantasy creatures in a tour-de-force of nerd crossover. Seriously, go read that piece if you haven’t. It has an alternate abstract in Elvish.

As with all phylogenetic studies, which reconstruct the historical relationships among living and extinct species that share common ancestors, Evangelista’s goal is to understand those relationships. To do this, he recorded a long list of characteristics for each species in his elf-tree — how tall are they? are they stocky or slim? do they like music? He then used a program called Mesquite to identify a set of evolutionary relationships that minimized the number of times those traits would have had to change, which we call the most parsimonious evolutionary tree.

This analysis produces at least one big surprise: it concludes that the closest relatives of the elves working in Santa’s workshop isn’t another type of elves, but dwarves.

A proposed phylogeny of elves and allied fantastical anthropoids (Evangelista 2015: Fig. 2)

Commenting on Evangelista (2015), Brian Maloney argues that this actually makes a lot of sense:

It has long been verified that the primary activity of the Christmas “Elf” is the mass crafting of intricate and durable playthings. This is highly reminiscent of the Dwarf compulsion to hand-craft durable but non-exquisite weapons and armor.

But really what Evangelista (2015) demonstrates is the limits of character-based phylogenetic reconstruction. He and most of the commenters on his article are trying to make conclusions about the evolution of traits using an evolutionary tree reconstructed from those traits, or traits closely related to them. Evangelista rated his taxa on “dexterity,” for instance, which for Christmas elves is basically identical to “crafting intricate and durable playthings.”

Moreover, we know that convergent evolution happens. Natural or artificial selection can shape distantly related species in similar ways, if they lead similar lifestyles. Extreme examples are the wings of bats and birds, or the streamlined, finned bodies of dolphins and fish. We know that bats and dolphins are mammals because of characteristics separate from flight and swimming ability, like fur or milk provision. In subtler cases, we more often identify convergent evolution of traits using a phylogeny based on DNA sequences. DNA-based phylogenies can be estimated from regions of the genome that we know have nothing to do with the traits we’re interested in, so they reflect evolutionary history (largely) independent of selection for potentially convergent traits.

As Evangelista notes, we have records of artificial selection in at least one group — the orcs, which were elves “selected” by Morgoth to be more useful for evil ends. We also know there’s a possibility of interbreeding — “lateral transfer” in the terms of one commenter — which can muddle relationships among groups we consider separate species. We have specific records of hybridization events with non-fanstastical hominoids for both elves and orcs, which implies broader inter-fertilty. DNA sequence data, preferably from many different parts of the genome, can also identify the probability and timing of those past “admixture” events.

Based on my own knowledge of the natural history of these species, I’d expect DNA data to resolve orcs as more closely related to the “True Elves,” and possibly place Christmas elves among the diminutive, mostly helpful Pixies. Dwarves, having a separate origin from Elves and Humans, might not even be properly placed on the same phylogeny, but at the very least I’d expect them to share a common ancestor with the Elves (sensu lato) near the base of the tree. Unfortunately, DNA samples from most of these taxa are not likely to be forthcoming any time soon. Though apparently one elf species is enjoying a population boom after colonizing a new habitat, shelves, most others are extirpated from human realms, or rare to the point that they may be extinct.

We have just a few nights left to prepare sticky-tape hair snares for the rooftops of Christmas-celebrating households, and maybe we can obtain usable DNA from swabs of ancient artifacts of power. Until someone manages all that, though, Evangelista (2015) will remain the best available reconstruction of these relationships.

Happy holidays from all of us molecular ecology nerds, and my sincerest apologies to Dominic Evangelista.

About Jeremy Yoder

Jeremy B. Yoder is an Associate Professor of Biology at California State University Northridge, studying the evolution and coevolution of interacting species, especially mutualists. He is a collaborator with the Joshua Tree Genome Project and the Queer in STEM study of LGBTQ experiences in scientific careers. He has written for the website of Scientific American, the LA Review of Books, the Chronicle of Higher Education, The Awl, and Slate.
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