The effects of fine-grained variation on heterosis in the earthworm Eisenia andrei (Oligochaeta)

• Main Author: Hart, David Eugene
• Format: Dissertation
• Language: English
• Subjects: biology, ecology; biology, genetics
• ISBN: 9780599303522; 0599303522

Heterosis is a centuries-old phenomenon that has been detected at the level of the gene by positive correlations between allozyme heterozygosity and various fitness-related traits. This study examined the effects of constant and fluctuating environments on heterosis vs. heterozygote inferiority measured as potence for six polymorphic loci in the earthworm Eisenia andrei. Neither heterosis nor heterozygote inferiority was promoted consistently by a fluctuating environment. The six loci responded differently to altered levels of soil temperature and/or moisture in both the constant and fluctuating environments. Potence was affected by interactions between locus and environment in the constant environments but not in the fluctuating environments. Fluctuation of the environment reduced the variation in the potence index observed in the constant environments, but it could not synchronize environmental effects on single loci efficiently enough to produce multilocus heterosis.