As breeding between relatives often results in inbreeding depression, inbreeding avoidance is widespread in the animal kingdom. However, inbreeding avoidance may entail fitness costs. For example, dispersal away from relatives may reduce survival. How these conflicting selection pressures are resolved is challenging to investigate, but theoretical models predict that inbreeding should occur fre...

We examined the effects of inbreeding on the performance of wood frog (Rana sylvatica) larvae in the field and in the laboratory. We used microsatellite analysis to establish the parentage and degree of inbreeding of the larvae. Two different estimators of inbreeding were used. The first was based on average multilocus heterozygosity, and the second was based on a molecular relatedness estimato...

High inbreeding depression is thought to be one of the major factors preventing evolutionary transitions in hermaphroditic plants from self-incompatibility (SI) and outcrossing toward self-compatibility (SC) and selfing. However, when selfing does evolve, inbreeding depression can be quickly purged, allowing the evolution of complete self-fertilization. In contrast, populations that show interm...

Many species avoid inbreeding through dispersal of individuals away from their natal groups or sites. Benthic marine invertebrates with long free-living larval stages generally possess great dispersal potential and are therefore expected to have a small chance of inbreeding in the field. Species that lack such dispersive larval stages should have a higher likelihood of inbreeding. If such direc...

Inbreeding-environment interactions occur when inbreeding leads to differential fitness loss in different environments. Inbred individuals are often more sensitive to environmental stress than are outbred individuals, presumably because stress increases the expression of deleterious recessive alleles or cellular safeguards against stress are pushed beyond the organism's physiological limits. We...

AST and JONES (1919) and CASTLE (1930) reviewed the significant experiE ments with plants and laboratory animals that contributed to the formulation of the modern viewpoints concerning the effects of inbreeding. The phenomena associated with inbreeding: decline in vigor, increased uniformity within the inbred stock, increased prepotency in outside crosses, isolation of abnormal types, etc., wer...

Understanding the fitness consequences of inbreeding (inbreeding depression) is of importance to evolutionary and conservation biology. There is ample evidence for inbreeding depression in captivity, and data from wild populations are accumulating. However, we still lack a good quantitative understanding of inbreeding depression and what influences its magnitude in natural populations. Specific...

One key objective in evolutionary ecology is to understand the magnitude of inbreeding depression expressed across sex-specific components of fitness. One major component of male fitness is fertilization success, which depends on male gametic performance (sperm and pollen performance in animals and plants, respectively). Inbreeding depression in male gametic performance could create sex-specifi...

Inbreeding depression is assumed to be a central factor contributing to the stability of plant mating systems. Predicting the fitness consequence of inbreeding in natural populations is complicated, however, because it may be affected by the mating histories of populations generating variation in the amount of purging of deleterious alleles. Furthermore, the level of inbreeding depression may d...

Animals most related or least related to current members of their breed were revealed by calculating the expected inbreeding of their future progeny. A sample of potential mates was chosen by randomly selecting 600 females from a recent birth year (1995). Relationships among the sample were computed by the tabular method. Relationships of other animals to the sample population were computed qui...