Dynamics of the B chromosome polymorphism in rye II. Estimates of parameters

Abstract

The computer simulation model presented in the first paper in this series identified six parameters which were considered to represent the main processes determining the transmission rates and distribution characteristics of the B chromosomes of rye. Basically it was found that a drive mechanism is provided by the directed nondisjunction of Bs at first pollen grain, and first egg cell, mitosis and that, the other parameters are largely concerned in modifying the drive and in regulating the final equilibrium B levels. The Bs were found to be “selfish” and to be capable of maintaining and dispersing themselves throughout populations even in the face of negative maladaptive effects upon reproductive and physiological fitness. In this paper estimates are presented, from published sources, of the real values of the parameters concerned. These estimates have been used to assess the application of the model and to determine the range and means of the parameters in relation to differing genetic and environmental influences. © 1983, The Genetical Society of Great Britain.