Genes are strange, and science has barely scratched the surface when it comes to determining which genes are responsible for what. Many are responsible for multiple characteristics, and some can switch roles depending on the situation. A pair of curious new studies give a rather weird example of this – by switching off a certain gene in horned dung beetles, their central horn turns into a compound eye instead, effectively turning them into cyclops beetles.
The first study, published in the Proceedings of the Royal Society B, found that the orthodenticle genes in horned beetles of the genus Onthophagus completely changed their head structure, with the replacement of their combat-ready horns being particularly strange. Weirder still, the physical consequences of this gene knockout were specific to this genus. When the same technique was applied to the hornless flour beetles (genus: Tribolium), nothing of the sort happened.
“We were amazed that shutting down a gene could not only turn off development of horns and major regions of the head, but also turn on the development of very complex structures such as compound eyes in a new location,” lead author Eduardo Zattara, a postdoctoral researcher at Indiana University Bloomington (IUB), said in statement.
“The fact that this doesn’t happen in Tribolium is equally significant, as it suggests that orthodenticle genes have acquired a new function: to direct head and horn formation only in the highly modified head of horned beetles.”
At this point, it isn’t clear why this change does occur when these genes are knocked out, which is where the second study, published in the Journal of Experimental Zoology, comes into play. Instead of focusing on dung beetles’ adult lives, the team of researchers focused on their development as larvae.
A close-up of the strange compound eyes in the center of the head. Indiana University Bloomington