Photo credit: Eduardo Zattara/Indiana University

Scientists have managed to genetically modify a common beetle to develop a third functional eye, right in the middle of its forehead. 

Such a study builds on previous research, whereby the team caused a beetle to grow a third eye accidentally. Both studies were led by Indiana University postdoctoral researcher Eduardo Zattara. The results of the study have been published in the journal PNAS.

Armin Moczec, researcher at at Indiana University, explained, “Instead, thousands of individual genes and dozens of developmental processes come together to enable the formation of each of these traits. We’ve also learned that evolving a novel physical trait is much like building a novel structure out of Lego bricks, by re-using and recombining ‘old’genes and developmental processes within new contexts.”

In the original research, the team switched off a gene that is involved in the development of the heads of dung beetles, which caused quite drastic changes to the structure of their heads. 

The work of Zattara’s team, was much simpler. Instead, they set out to intentionally grow a third eye in two types of scarab beetle, Onthophagini and Oniticellini, by wiping out just a single gene, the same head development gene from their earlier research. 

The third eye that was formed was in fact a result of a fused pair of eyes. They also lost their horns, or grew smaller ones, consistent with the earlier research. The team carried out a number of multiple tests to confirm that the new eye had the same cell types, genes, nerves connections and behavioural responses as a normal eye.

Moczek concluded, “This study experimentally disrupts the function of a single, major gene. And, in response to this disruption, the remainder of head development reorganises itself to produce a highly complex trait in a new place: a compound eye in the middle of the head.”

The research has the potential to enable researchers to further understand how organs develop and become part of a body, and such knowledge could prove useful in the development of artificial lab-grown organs, both research, as well as medical purposes.