Stress Resistance and Environmental Dependency of Inbreeding Depression in Drosophila melanogaster

Abstract

Both inbreeding and environmental stress can have adverse effects on fitness that affect the conservation of endangered species. Two important issues are whether stress and inbreeding effects are independent as opposed to synergistic, and whether inbreeding effects are general across stresses as opposed to stress‐specific. We found that inbreeding reduced resistance to acetone and desiccation in adult Drosophila melanogaster, whereas resistance to knockdown heat stress was not affected. Inbred flies, however, experienced a greater proportional decrease in productivity than outbreds following heat stress. Correlations using line means indicated that all resistance traits were uncorrelated in the inbred as well as in the outbred flies. Recessive, deleterious alleles therefore did not appear to have any general deleterious effects on stress resistance. Inbreeding within a specific environment and selection for resistant genotypes may therefore purge a population of deleterious genes specific to only one environmental stress.

Environmental quality and evolutionary potential: lessons from wild populations

“…While investigating the relationship between inbreeding and environmental stress through laboratory tests on Drosophila melanogaster, Dahlgaard & Hoffmann (2000) illustrated that influences of different types of stresses are not always genetically correlated. Differences between environments in table 1 are variable (e.g.…”

“…When discussing differences between studies on agricultural animals (controlled breeding) and studies on Drosophila, Hoffmann & Parsons (1991) argued that extreme environmental stresses in the latter (e.g. ethanol combined with cold shock and low nutrition in Sgro & Hoffmann (1998a) and acetone or desiccation resistance in Dahlgaard & Hoffmann (2000)) could result in drastic changes such as expressions of new sets of genes, whereas mild changes in the latter would trigger different changes.…”

Changes in the expression of genetic characteristics across cohorts in skeletal deformations of farmed salmonids

“…Although speculative, the most likely reason is that different stressors are present during different years, and thus, deformations at different generations do not share common genetic determination. Likewise, work on a fruit fly Drosophila melanogaster has illustrated that effects of different types of stress are not always strongly genetically correlated [5]. In fish, genetic correlations between multiple diseases, in turn, have been either positive, negative or approximately zero [9,11,13].…”

“…The factors causing deformations do not need to be the same in all cohorts, and deformations induced by different stressors need not share common genetic origin. Thus, there may even be genetic trade-offs (i.e., negative genetic correlations) between resistance mechanisms against alternative stressors [5].…”

Analysis of the effects of inbreeding on lifespan and starvation resistance in Drosophila melanogaster

“…In general, because of their decreased overall fitness and genetic variability inbred individuals are expected to be more sensitive to changing environmental conditions than their outbred conspecifics (see e.g. Bijlsma et al 1999Bijlsma et al , 2000Dahlgaard and Hoffmann 2000;Kristensen et al 2003Kristensen et al , 2010Reed et al 2003;Armbruster and Reed 2005;Swindell and Bouzat 2006b;Liao and Reed 2009). This has also been suggested to decrease survival and lifespan under most circumstances (Vermeulen and Bijlsma 2004).…”