The beautiful Heliconius butterflies from Central and South Africa are known for their colorful wing patterns. Some of their wing patterns mimic that of other species to protect them from their predators. There is one species of these evolutionary marvels, Heliconius cydno, that scientists have found that the activation of a single gene can determine whether the butterfly expresses white or yellow spots. To come to this conclusion scientists created a genetic map of H.cydno with both white and yellow coloring.
Through examining the genetic maps, the researchers found that the gene al1 was switched on in the white colored butterflies which would mean that al1 gene was correlated to the production of yellow pigmentation. To test this the researchers used CRISPR (a gene editing tool) to switch off the al1 gene in what was supposed to be white spotted butterfly embryo. They found that by switching off that gene the butterflies developed with yellow spots.
The researchers that carried out this experiment also looked into the evolutionary history of these butterflies since this experiment didn’t add pigmentation to the butterflies but changed an ancestrally present pigment by switching off a gene through CRISPR. They studied the al1 gene to butterflies that are closely related to the Heliconius species and found that white version of the spots is a recent development and that H.cyndo was first species to develop the white spots.
After further examination, there was evidence that the white version of the spots corresponds to matting patterns. So, the white spotted H.cydno males preferred to mate with the white spotted H.cyndo females and vise versa with the yellow spotted H.cydno males to H.cydno females. Which begs the question of what roles does the activation of al1 play in not only the coloration of these butterflies but also evolutionarily going forward? If gene activation through CRISPR continues how will that also affect the future mating patterns of these butterflies but possible of other species too?