Genetical Research

Dynamics of transposable elements under the selection model

A. TSITRONE a1p1, S. CHARLES a1 and C. BIÉMONT a1c1
a1 Laboratoire de Biométrie, Génétique, Biologie des populations, UMR CNRS 5558, Université Lyon 1, 69622 Villeurbanne Cedex, France


We examine an analytical model of selection against the deleterious effects of transposable element (TE) insertions in Drosophila, focusing attention on the asymptotic and dynamic characteristics. With strong selection the only asymptotically stable equilibrium point corresponds to extinction of the TEs. With very weak selection a stable and realistic equilibrium point can be obtained. The dynamics of the system is fast for strong selection and slow, on the human time scale, for weak selection. Hence weak selection acts as a force that contributes to the stabilization of mean TE copy number. The consequence is that under weak selection, and ‘out-of-equilibrium’ situation can be maintained for a long time in populations, with mean TE copy number appearing stabilized.

(Received December 10 1998)
(Revised March 5 1999)

c1 Corresponding author: Tel: (+33) 4 72 44 81 98. Fax: (+33) 4 78 89 27 19. e-mail:
p1 Present address: CEFE/CNRS, 1919, Route de Mende, 34293 Montpellier cedex 5, France.