title: Inbreeding-stress interactions: evolutionary and conservation consequences.
abstract: The effect of environmental stress on the magnitude of inbreeding depression has a long history of intensive study. Inbreeding-stress interactions are of great importance to the viability of populations of conservation concern and have numerous evolutionary ramifications. However, such interactions are controversial. Several meta-analyses over the last decade, combined with omic studies, have provided considerable insight into the generality of inbreeding-stress interactions, its physiological basis, and have provided the foundation for future studies. In this review, we examine the genetic and physiological mechanisms proposed to explain why inbreeding-stress interactions occur. We specifically examine whether the increase in inbreeding depression with increasing stress could be due to a concomitant increase in phenotypic variation, using a larger data set than any previous study. Phenotypic variation does usually increase with stress, and this increase can explain some of the inbreeding-stress interaction, but it cannot explain all of it. Overall, research suggests that inbreeding-stress interactions can occur via multiple independent channels, though the relative contribution of each of the mechanisms is unknown. To better understand the causes and consequences of inbreeding-stress interactions in natural populations, future research should focus on elucidating the genetic architecture of such interactions and quantifying naturally occurring levels of stress in the wild.
authors.affiliation: Department of Biology, University of Louisville, Louisville, Kentucky, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Reed
authors.forename: Charles W
authors.initials: CW
authors.lastname: Fox
authors.forename: Laramy S
authors.initials: LS
authors.lastname: Enders
authors.forename: Torsten N
authors.initials: TN
authors.lastname: Kristensen
mesh_terms: D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D003247:Conservation of Natural Resources; D004777:Environment; D040741:Genetic Load; D014644:Genetic Variation; D007178:Inbreeding; D008957:Models, Genetic; D010641:Phenotype; D013312:Stress, Physiological