Population biology: The ecology of inbreeding depression

Po, Cheptou

doi:10.1038/sj.hdy.6800768

Cited by 7 publications

(8 citation statements)

References 10 publications

(10 reference statements)

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“…In the present study the effect of inbreeding is clearly evident although the sample size is relatively small as the rough terrain on Isabela Island prohibited more crossings. Also, under natural growth conditions inbreeding depression is likely to be even higher than that found here due to a stressful environment (Armbruster and Reed 2005;Cheptou 2006). There was no significant among-family variation in inbreeding depression as previously documented in various studies (e.g.…”

Section: Discussionmentioning

confidence: 79%

Inbreeding depression in the partially self-incompatible endemic plant species Scalesia affinis (Asteraceae) from Galápagos islands

2006

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A previous study showed that some individuals of the tetraploid Galápagos endemic Scalesia affinis were able to produce offspring after selfing. The present study compares the fitness of self-pollinated offspring with the fitness of cross-pollinated offspring. Germination success, seedling survival, and four different growth parameters was measured. In most of the studied characters selfed offspring were significantly inferior to outcrossed progeny. The effect was very clear in germination and survival. Outcrossed embryos were 3.4 times more likely to germinate than those that were selfed-fertilized, and the mortality was 84% higher among selfed individuals. Also, there was no genetic variation in inbreeding depression. The present study is based on material from a large population on Isabela Island, Galápagos. At other localities in the archipelago, populations have been through recent dramatic bottlenecks due to the grazing of introduced mammals. Considering the significant inbreeding depression found in the large population and the presence of a partial self-incompatibility system, these small populations are likely to be highly vulnerable and their future survival critically threatened.

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Section: Discussionmentioning

confidence: 79%

Inbreeding depression in the partially self-incompatible endemic plant species Scalesia affinis (Asteraceae) from Galápagos islands

2006

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“…However, the correlation between the measured selfing rate and the proportion of viable seed was not significant in this study, which may be due to the variation of inbreeding depression adjusted by patch openness (Selfing and Open%, = 0.524, P = 0.018, Table 4). For a light loving species like Chinese pine, higher patch openness means more available light within the patch, which may reduce the abortion rate of selfed offspring (Armbruster and Reed, 2005;Cheptou, 2005) and thus more selfed offspring can survive to the filled seed stage to be measured. Nonetheless, the improvement does not change the trend of smaller patches having fewer viable seeds.…”

Section: Discussionmentioning

confidence: 99%

Effect of patch size and isolation on mating patterns and seed production in an urban population of Chinese pine (Pinus tabulaeformis Carr.)

Wang

Sork

et al. 2010

Forest Ecology and Management

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“…It has been repeatedly noted that the impact of individual inbreeding depression varies with environment [46,47], and the negative effects of high levels of inbreeding may be masked by permissive environments or when a direct comparison with outbred individuals is not possible [6,12,48]. In experimental settings, inbreeding depression is usually, but not universally, stronger in stressful environments [46].…”

Section: Discussionmentioning

confidence: 99%

Population genetic diversity and fitness in multiple environments

et al. 2010

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BackgroundWhen a large number of alleles are lost from a population, increases in individual homozygosity may reduce individual fitness through inbreeding depression. Modest losses of allelic diversity may also negatively impact long-term population viability by reducing the capacity of populations to adapt to altered environments. However, it is not clear how much genetic diversity within populations may be lost before populations are put at significant risk. Development of tools to evaluate this relationship would be a valuable contribution to conservation biology. To address these issues, we have created an experimental system that uses laboratory populations of an estuarine crustacean, Americamysis bahia with experimentally manipulated levels of genetic diversity. We created replicate cultures with five distinct levels of genetic diversity and monitored them for 16 weeks in both permissive (ambient seawater) and stressful conditions (diluted seawater). The relationship between molecular genetic diversity at presumptive neutral loci and population vulnerability was assessed by AFLP analysis.ResultsPopulations with very low genetic diversity demonstrated reduced fitness relative to high diversity populations even under permissive conditions. Population performance decreased in the stressful environment for all levels of genetic diversity relative to performance in the permissive environment. Twenty percent of the lowest diversity populations went extinct before the end of the study in permissive conditions, whereas 73% of the low diversity lines went extinct in the stressful environment. All high genetic diversity populations persisted for the duration of the study, although population sizes and reproduction were reduced under stressful environmental conditions. Levels of fitness varied more among replicate low diversity populations than among replicate populations with high genetic diversity. There was a significant correlation between AFLP diversity and population fitness overall; however, AFLP markers performed poorly at detecting modest but consequential losses of genetic diversity. High diversity lines in the stressful environment showed some evidence of relative improvement as the experiment progressed while the low diversity lines did not.ConclusionsThe combined effects of reduced average fitness and increased variability contributed to increased extinction rates for very low diversity populations. More modest losses of genetic diversity resulted in measurable decreases in population fitness; AFLP markers did not always detect these losses. However when AFLP markers indicated lost genetic diversity, these losses were associated with reduced population fitness.

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Population biology: The ecology of inbreeding depression

Cited by 7 publications

References 10 publications

Inbreeding depression in the partially self-incompatible endemic plant species Scalesia affinis (Asteraceae) from Galápagos islands

Inbreeding depression in the partially self-incompatible endemic plant species Scalesia affinis (Asteraceae) from Galápagos islands

Effect of patch size and isolation on mating patterns and seed production in an urban population of Chinese pine (Pinus tabulaeformis Carr.)

Population genetic diversity and fitness in multiple environments

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