B-chromosome drive

Jones, RN,  American Naturalist,  137:430-442. 1991.

The view of B-chromosome polymorphisms that is coming into favor resembles the so-called “parasitic” model, which was first advanced 45 yr ago. Since that time, repeated and ongoing efforts have been made to ascribe an adaptive role to B’s (e.g., in terms of phenotypic advantage, effects of variability, etc.), but success in this direction has been singularly lacking. Consistently and repeatedly, the data indicate that harmful effects, or at best neutral or undetectable effects, are associated with B’s and provide evidence of the potency of accumulation mechanisms based on drive. Modeling exercises have proved useful in examining these polymorphisms, and of the ones that have been published to date, all have favored drive as the main force generating B-chromosome polymorphisms.