PITTSBURGHDetermining the evolution of pigmentation patterns on mollusk seashellswhich could aid in the understanding of ancient nervous systemshas proved to be a challenging feat for researchers. Now, however, through mathematical equations and simulations, University of Pittsburgh and University of California, Berkeley, researchers have used 19 different species of the predatory sea snail Conus to generate a model of the pigmentation patterns of mollusk shells.
"There is no evolutionary record of nervous systems, but what you're seeing on the surface of seashells is a space-time record, like the recording of brain-wave activity in an electroencephalogram (EEG)," said project coinvestigator G. Bard Ermentrout, Pitt Distinguished University Professor of Computational Biology and a professor in the Kenneth P. Dietrich School of Arts and Sciences' Department of Mathematics.
Seashells differ substantially between the closely related Conus species, and the complexity of the patterns makes it difficult to properly characterize their similarities and differences. It also has proven difficult to describe the evolution of pigmentation patterns or to draw inferences about how natural selection might affect them. In a paper published in the Jan. 3 issue of the Proceedings of the National Academy of Sciences (PNAS) Online, Ermentrout and his colleagues attempt to resolve this problem by combining models based on natural evolutionary relationships with a realistic developmental model that can generate pigmentation patterns of the shells of the various Conus species.
In order for UC Berkeley scientists to create simulations, Ermentrout and his collaborators developed equations and a neural model for the formation of the pigmentation patterns on shell surfaces. With the equations in hand, Zhenquiang Gong, a UC Berkeley graduate student in engineering, used a computer to simulate the patterns on the shells, hand
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University of Pittsburgh