Clark University biology professor receives NSF grant to study lizard limb re-evolution

Philip Bergmann Philip Bergmann

Philip Bergmann, assistant professor in the Department of Biology at Clark University, has been awarded a $153,155 grant from the National Science Foundation for his three-year project "Developmental and functional mechanisms of complex trait re-evolution: limb loss and gain in skink lizards."

"This grant is a wonderful opportunity to address some fundamental questions in evolutionary biology," says Bergmann, who will travel to the Philippines to conduct his research. "It also allows me to collaborate with other scientists with expertise different from my own." The NSF grant will make it possible for Bergmann to include students more closely in his research.

Studying skink behavior Studying skink behavior

"Grad students will have the opportunity to accompany me to the Philippines to collect data, and undergraduates will participate in the study of the high-speed videos and other data collected in the field," he explains. "This involvement allows students to gain hands-on research experience that will help prepare them to be successful scientists."

A widely accepted hypothesis introduced in 1893 as Dollo's Law states that once an organism loses a trait (an inherited characteristic like fur or a tail) during the course of its evolutionary development, that trait cannot re-appear subsequently through evolution. But a growing list of examples to the contrary, including some species of skink lizard, is causing scientists like Bergmann to reevaluate that law. Bergmann explains that no one has considered how or why evolution would seemingly reverse course in a way that leads to the re-evolution of complex traits. His research team will be the first to address these questions.

A skink with five digits on each limb A skink with five digits on each limb


A skink with reduced limbs A skink with reduced limbs


Bergmann's project will focus on an example of apparent re-evolution occurring among a group of skink lizards belonging to the genus Brachymeles. While these skinks have evolved to be snake-like, with elongated bodies and no limbs, some species within the genus have subsequently re-evolved their limbs and shortened their bodies. The team will examine how these traits of body length and limbs evolve, how they can be lost and then subsequently re-evolve. The researchers will explore questions surrounding whether the same genes are involved in the development of both "ancestral" limbs and re-evolved limbs, and how well skinks with ancestral limbs run and burrow, compared to those with re-evolved limbs.

Professor Bergmann's research takes a broadly integrative approach to studying the evolution and diversification of functional morphological systems. A central research focus is the evolution of body shape and function and how this influences locomotion and habitat use.