Penn Biologists Find that Evolution is Unpredictable and Irreversible

In a paper published in the Proceedings of the National Academy of Sciences, University of Pennsylvania researchers show that evolution is both unpredictable and irreversible. Using simulations of an evolving protein, the researchers found that genetic mutations accepted via the process of evolution are usually dependent on prior mutations, and that once the mutations are accepted they become increasingly difficult to reverse. The team was comprised of postdoctoral researchers Premal Shah and David M. McCandlish in the Department of Biology, and Professor of Biology Joshua B. Plotkin.

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Arts & Sciences News

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University of Pennsylvania, Neubauer Family Foundation, and Philadelphia Police Department Partner to Support Police Leadership Education

The first-of-its-kind graduate degree in the U.S. for police leaders launches this fall at the School of Arts & Sciences.

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Marisa C. Kozlowski Named Next Associate Dean for the Natural Sciences

Kozlowski, who joined the Penn faculty in 1997, succeeds Mark Trodden, who transitions to the Dean of Penn Arts & Sciences on June 1.

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One Fourth Year, One Alum Receive 2025 Hertz Fellowship

Eric Tao, C’25, Gr’25 (left), and Suraj Chandran, C’23, were awarded the honor, part of a group of 19 fellows selected this year. Each one receives five years of funding toward a doctoral program.

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Benjamin Nathans Wins 2025 Pulitzer Prize in General Nonfiction

Nathans, Alan Charles Kors Endowed Term Professor of History, won for his book “To the Success of Our Hopeless Cause: The Many Lives of the Soviet Dissident Movement.”

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Mark Devlin Elected to National Academy of Sciences

He joins three others from Penn to receive the honor this year, all recognized for “distinguished and continuing achievements in original research.”

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Michael Jones-Correa and Sophia Rosenfeld Elected to American Academy of Arts & Sciences

They join three others from the University of Pennsylvania, selected as part of the Academy’s mission to convene leaders from “every field of human endeavor to examine new ideas, address issues of importance to the nation and the world, and work together.”

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