One tenet of natural selection is a random walk of genes but nature may be more predictable than rolls of dice suggest. A new study of the mimicry of several distantly-related South American rainforest butterfly and moth species with similar wing color patterns that may warn away predators (it's not a costumed bluff, the moths and butterflies are actually toxic to birds) found that they reused the same two genes - ivory and optix - to evolve near identical color patterns.

Isn't that just convergent evolution? The link is not due to a common ancestor but in how the genes are switched on. The moth species used an inversion mechanism, DNA flipped backwards, like one of the butterflies. It's rare to lock in on how and even when unrelated species independently evolved the same trait. It means that evolution can be a lot more predictable than believed, and that butterflies and moths have been using the exact same genetic tricks repeatedly to achieve similar color patterns since dinosaurs roamed. 


Zoomed Manhattan plots of genome-wide association for wing pattern variation involving (A) ivory and (B) optix. SNPs above the Bonferroni-corrected significance threshold (orange dashed line) are colored according to the strength of correlation (ρ2, squared Spearman’s rank correlation coefficient) between genotype and the phenotypes compared as shown in the wing images. Black points represent SNPs fully associated with the phenotypes. The bottom Manhattan plot shows the wider ~1 Mb region of high association in Chetone histrio around the ivory region. The results for Heliconius numata were retrieved from [28]. Heliconius pardalinus results are based on QTL mapping (S16 Fig). E230: cis-regulatory element 230 [29]; ivory pro.: ivory promoter; hyd. like: hydrolyze like; LRR1: Leucine Rich Repeat Protein 1. Association plots across the whole-genome are shown in S2 Fig. The ~ 400 kb P1 inversion (orange segment) is associated with color pattern variation in Heliconius numata [28,30] and corresponds closely in location to the Chetone histrio inversion as shown by the red segment (S24 Fig).

“Here, we show that these warning colors are particularly ideal as it seems quite easy to evolve these same color patterns due to the highly conserved genetic basis over 120 million years,” said Professor Joana Meier from the Wellcome Sanger Institute. 

Knowing that nature follows a particular route, and is not as ‘random’ as once thought, helps scientists predict how other species might adapt to their environments.

Citation: Ben Chehida Y, van der Heijden ESM, Page E, Salazar C PA, Rosser N, Córdova KGG, et al. (2026) Genetic parallelism underpins convergent mimicry coloration in Lepidoptera across 120 million years of evolution. PLoS Biol 24(4): e3003742. https://doi.org/10.1371/journal.pbio.3003742