But, when the team mapped the regions of the genome controlling the jaw-opening system, they found that these levers are controlled by different chromosomes.
In another part of the study, researchers showed that the gene bmp4 is a major factor in controlling the jaw-closing system. When the team injected bmp4 protein into the developing embryos of another fish species, the zebrafish, they saw that the mechanical advantage (and thus the biting power) of the jaw increased.
"This experiment fuses the traditional disciplines of developmental genetics and evolutionary biology," said Streelman. "We've demonstrated that important functional differences operating in adult organisms are elicited by changes in early development. Our next goal is to understand the genetic bases underlying the differences between the simple biomechanical system of the lower jaw and complex systems of the anterior jaw in these fish."