fitness flux & ubiquity of adaptive evolution -- Dinosauria implications?
Ville Mustonen & Michael Laessig, 2010. Fitness flux and ubiquity of adaptive evolution. Proc. National Academy of Sciences 107(9):4248-4253 + Corrected Supporting Information. ABSTRACT. Natural selection favors fitter variants in a population, but actual evolutionary processes may decrease fitness by mutations and genetic drift. How is the stochastic evolution of molecular biological systems shaped by natural selection? Here, we derive a theorem on the fitness flux in a population, defined as the selective effect of its genotype frequency changes. The fitness-flux theorem generalizes Fisher’s fundamental theorem of natural selection to evolutionary processes including mutations, genetic drift, and time-dependent selection. It shows that a generic state of populations is adaptive evolution: there is a positive fitness flux resulting from a surplus of beneficial over deleterious changes. In particular, stationary nonequilibrium evolution processes are predicted to be adaptive. Under specific nonstationary conditions, notably during a decrease in population size, the average fitness flux can become negative. We show that these predictions are in accordance with experiments in bacteria and bacteriophages and with genomic data in Drosophila. Our analysis establishes fitness flux as a universal measure of adaptation in molecular evolution.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~STEPHAN PICKERING / Chofetz Chayim ben-AvrahamJewish dinosaurologist / Heretic spiritistTHE DINOSAUR FRACTALS PROJECT2333 Portola Drive # 4Santa Cruz, California 95062-4250IN PROGRESS: Mutanda Dinosaurologica: in memory of Samuel Paul Welles (9 November 1909--6 August 1997)IN PROGRESS: Dialects of a synaesthetic heart: poetics for Faline Pickering (23 January 1949--24 August 2008)IN PROGRESS: Alfred Russel Wallace's KING KONG: the semioptics of Willis O'BrienPARTNER IN THE UNIVERSE TO: FALINE PICKERING, MY BELOVED QUANTUM PISCESMEMBER 13853: Society of Vertebrate PaleontologyOne concept corrupts and confuses the others. I am not speaking of the Evil whose limited sphere is ethics; I am speaking of the infinite. -- J.L. BORGESYou never know what's comin' for you. -- QUEENIE in ERIC ROTH'S The curious case of Benjamin ButtonWhat if G-d didn't say it? -- BART EHRMAN