The inbreeding depression cost of selfing: Importance of flower size and population size inCollinsia parviflora(Veronicaceae)

2008 ◽  
Vol 95 (12) ◽  
pp. 1596-1605 ◽  
Author(s):  
Brad F. Kennedy ◽  
Elizabeth Elle
Keyword(s):  
Population Size ◽  
Inbreeding Depression ◽  
Flower Size

scholarly journals Lethals in subdivided populations

2005 ◽  
Vol 86 (1) ◽  
pp. 41-51 ◽  
Author(s):  
SYLVAIN GLÉMIN
Keyword(s):  
Population Structure ◽  
Population Size ◽  
Inbreeding Depression ◽  
Deleterious Mutations ◽  
Mutation Load ◽  
General Picture ◽  
Analytical Approximations ◽  
Size Population ◽  
Subdivided Populations ◽  
Numerical Approaches

The fate of lethal alleles in populations is of interest in evolutionary and conservation biology for several reasons. For instance, lethals may contribute substantially to inbreeding depression. The frequency of lethal alleles depends on population size, but it is not clear how it is affected by population structure. By analysing the case of the infinite island model by numerical approaches and analytical approximations it is shown that, like population size, population structure affects the fate of lethal alleles if dominance levels are low. Inbreeding depression caused by such alleles is also affected by the population structure, whereas the mutation load is only weakly affected. Heterosis also depends on population structure, but it always remains low, of the order of the mutation rate or less. These patterns are compared with those caused by mildly deleterious mutations to give a general picture of the effect of population structure on inbreeding depression, heterosis, and the mutation load.

scholarly journals Inbreeding depression due to mildly deleterious mutations in finite populations: size does matter

2000 ◽  
Vol 75 (1) ◽  
pp. 75-81 ◽  
Author(s):  
THOMAS BATAILLON ◽  
MARK KIRKPATRICK
Keyword(s):  
Population Size ◽  
Inbreeding Depression ◽  
Deleterious Mutation ◽  
Large Population ◽  
Genetic Load ◽  
Breeding Systems ◽  
Deleterious Mutations ◽  
Single Locus Analysis ◽  
Population Sizes ◽  
Inbreeding Rate

We studied the effects of population size on the inbreeding depression and genetic load caused by deleterious mutations at a single locus. Analysis shows how the inbreeding depression decreases as population size becomes smaller and/or the rate of inbreeding increases. This pattern contrasts with that for the load, which increases as population size becomes smaller but decreases as inbreeding rate goes up. The depression and load both approach asymptotic limits when the population size becomes very large or very small. Numerical results show that the transition between the small and the large population regimes is quite rapid, and occurs largely over a range of population sizes that vary by a factor of 10. The effects of drift on inbreeding depression may bias some estimates of the genomic rate of deleterious mutation. These effects could also be important in the evolution of breeding systems in hermaphroditic organisms and in the conservation of endangered populations.

Reduced population size can induce quick evolution of inbreeding depression in the invasive ladybird Harmonia axyridis

2016 ◽  
Vol 18 (10) ◽  
pp. 2871-2881 ◽  
Author(s):  
Guillaume J. M. Laugier ◽  
Gilles Le Moguédec ◽  
Wang Su ◽  
Ashraf Tayeh ◽  
Laurent Soldati ◽  
...  
Keyword(s):  
Population Size ◽  
Inbreeding Depression ◽  
Harmonia Axyridis

scholarly journals Population structures and seasons affected flowering, pollination and reproductive outputs of sandalwood in Gunung Sewu, Java, Indonesia

2018 ◽  
Vol 10 (1) ◽  
pp. 12-26 ◽  
Author(s):  
YENI W.N. RATNANINGRUM ◽  
SAPTO INDRIOKO ◽  
ENY FARIDAH ◽  
ATUS SYAHBUDIN
Keyword(s):  
Population Size ◽  
Inbreeding Depression ◽  
Rainy Season ◽  
Flowering Period ◽  
Reproductive Parameters ◽  
The South ◽  
South Eastern ◽  
Population Structures

Ratnaningrum YWN, Indrioko S, Faridah E, Syahbudin A. 2018. Population structures and seasons affected flowering, pollination and reproductive outputs of sandalwood in Gunung Sewu, Java, Indonesia. Nusantara Bioscience 10: 12-26. Sandalwood was the origin to the south-eastern islands of Indonesia, but is recently occurred as new landraces in Gunung Sewu Geopark, Java, Indonesia. This study compared flowering and pollination, and their effect on reproductive outputs, among sandalwood populations in Gunung Sewu, during the dry and rainy season of 2016 flowering period. Flowering and pollination rate differed significantly between seasons but were similar among sites. Oppositely, reproductive outputs differed significantly among sites, but were similar between seasons. The rainy season produced more flowers and pollination. Pollination was less correlated to flowers abundance, but more affected by population size. The higher and cooler population visited more by Dipterans (31.8% to 32.6%) and Hymenopterans (28.2% to 30%), while the warmer, lower sites dominated by Lepidopterans (37.2% to 43%) and Dipterans (32.9% to 38.2%). Higher population received fewer visits, but more visitors diversity (28 families). In contrast, lower sites received more visits, but with less diversity (20 families). Most insect families were considered “Rare” and “Occasional”. However, pooled altogether, the whole families of Lepidopterans and Dipterans considered “Frequent” and “Effective”. The Hymenopterans considered “Frequent” and “Effective” at Nglanggeran and Wanagama. The Cicadellidae of Coleopterans, along with arachnids and grasshoppers, were considered robbers. All of the agents were diurnal. However, the time of activity was varied. Rainy season gained more flowers and visits, but in contrast, resulted in fewer fruits at all sites. Both flowers abundance and pollination were negatively correlated to the reproductive parameters. Populations might gain more flowers and visits, but the reproductive outputs were significantly lower. Particularly in the clonalized and lower heterozygosity populations, more flowers increased geitonogamy which may lead to inbreeding depression.

scholarly journals Slow recovery from inbreeding depression generated by the complex genetic architecture of segregating deleterious mutations

2019 ◽  
Author(s):  
Paula E. Adams ◽  
Anna L. Crist ◽  
Ellen M. Young ◽  
John H. Willis ◽  
Patrick C. Phillips ◽  
...  
Keyword(s):  
Population Size ◽  
Inbreeding Depression ◽  
Evolutionary Biology ◽  
Large Population ◽  
Genomic Diversity ◽  
List Type ◽  
Reproductive Systems ◽  
Genomic Changes ◽  
Deleterious Alleles ◽  
Sister Mating

AbstractThe deleterious effects of inbreeding have been of extreme importance to evolutionary biology, but it has been difficult to characterize the complex interactions between genetic constraints and selection that lead to fitness loss and recovery after inbreeding. Viruses, bacteria, and the selfing nematode Caenorhabditis elegans have been shown to be capable of rapid recovery from the fixation of novel deleterious mutation, however the potential for fitness recovery from fixation of segregating variation under inbreeding in outcrossing organisms is poorly understood. C. remanei is an outcrossing relative of C. elegans with high polymorphic variation and extreme inbreeding depression. Here we sought to characterize changes C. remanei in patterns of genomic diversity after ∼30 generations of inbreeding via brother-sister mating followed by several hundred generations of recovery at large population size. As expected, inbreeding led to a large decline in reproductive fitness, but unlike results from mutation accumulation experiments, recovery from inbreeding at large populations sizes generated only very moderate recovery in fitness after 300 generations. At the genomic level, we found that while 66% of ancestral segregating SNPs were fixed in the inbred population, this was far fewer than expected under neutral processes. Under recovery, 36 SNPs across 30 genes involved in alimentary, muscular, nervous and reproductive systems changed reproducibly across all replicates, indicating that strong selection for fitness recovery does exist but is likely mutationally limited due to the large number of potential targets. Our results indicate that recovery from inbreeding depression via new compensatory mutations is likely to be constrained by the large number of segregating deleterious variants present in natural populations, limiting the capacity for rapid evolutionary rescue of small populations.Impact SummaryInbreeding is defined as mating between close relatives and can have a large effect on the genetic diversity and fitness of populations. This has been recognized for over 100 years of study in evolutionary biology, but the specific genomic changes that accompany inbreeding and the loss of fitness are still not known. Evolutionary theory predicts that inbred populations lose fitness through the fixation of many deleterious alleles and it is not known if populations can recover fitness after prolonged periods of inbreeding and deleterious fixations, or how long recovery may take. These questions are particularly important for wild populations experiencing declines. In this study we use laboratory populations of the nematode worm Caenorhabditis remanei to analyze the loss of fitness and genomic changes that accompany inbreeding via brother-sister mating, and to track the populations as they recover from inbreeding at large population size over 300 generations. We find that: Total progeny decreased by 65% after inbreedingThere were many nucleotides in the genome that remained heterozygous after inbreedingThere was an excess of inbreeding-resistant nucleotides on the X chromosomeThe number of progeny remained low after 300 generations of recovery from inbreeding30 genes changed significant in allele frequency during recovery, including genes involved in the alimentary, muscular, nervous and reproductive systemsTogether, our results demonstrate that recovery from inbreeding is difficult, likely due to the fixation of numerous deleterious alleles throughout the genome.

scholarly journals Genetic Allee effects and their interaction with ecological Allee effects

2016 ◽  
Author(s):  
Meike J. Wittmann ◽  
Hanna Stuis ◽  
Dirk Metzler
Keyword(s):  
Population Size ◽  
Inbreeding Depression ◽  
Survival Probability ◽  
Allee Effect ◽  
Extinction Risk ◽  
List Type ◽  
Small Populations ◽  
Allee Effects ◽  
Deleterious Mutations ◽  
Lethal Equivalents

SummaryIt is now widely accepted that genetic processes such as inbreeding depression and loss of genetic variation can increase the extinction risk of small populations. However, it is generally unclear whether extinction risk from genetic causes gradually increases with decreasing population size or whether there is a sharp transition around a specific threshold population size. In the ecological literature, such threshold phenomena are called “strong Allee effects” and they can arise for example from mate limitation in small populations.In this study, we aim to a) develop a meaningful notion of a “strong genetic Allee effect”, b) explore whether and under what conditions such an effect can arise from inbreeding depression due to recessive deleterious mutations, and c) quantify the interaction of potential genetic Allee effects with the well-known mate-finding Allee effect.We define a strong genetic Allee effect as a genetic process that causes a population’s survival probability to be a sigmoid function of its initial size. The inflection point of this function defines the critical population size. To characterize survival-probability curves, we develop and analyze simple stochastic models for the ecology and genetics of small populations.Our results indicate that inbreeding depression can indeed cause a strong genetic Allee effect, but only if individuals carry sufficiently many deleterious mutations (lethal equivalents) on average and if these mutations are spread across sufficiently many loci. Populations suffering from a genetic Allee effect often first grow, then decline as inbreeding depression sets in, and then potentially recover as deleterious mutations are purged. Critical population sizes of ecological and genetic Allee effects appear to be often additive, but even superadditive interactions are possible.Many published estimates for the number of lethal equivalents in birds and mammals fall in the parameter range where strong genetic Allee effects are expected. Unfortunately, extinction risk due to genetic Allee effects can easily be underestimated as populations with genetic problems often grow initially, but then crash later. Also interactions between ecological and genetic Allee effects can be strong and should not be neglected when assessing the viability of endangered or introduced populations.

Minimum viable population size for lake sturgeon (Acipenser fulvescens) using an individual-based model of demographics and genetics

2011 ◽  
Vol 68 (1) ◽  
pp. 62-73 ◽  
Author(s):  
Amy M. Schueller ◽  
Daniel B. Hayes
Keyword(s):  
Population Size ◽  
Inbreeding Depression ◽  
Extinction Risk ◽  
Lake Sturgeon ◽  
Acipenser Fulvescens ◽  
Demographic Stochasticity ◽  
Individual Based Model ◽  
Viable Population ◽  
Minimum Viable Population Size ◽  
Minimum Viable Population

Population viability analysis is a useful tool to explore the relationship between extinction risk and population size, but often does not include genetic factors. Our objectives were to determine minimum viable population size (MVP) for lake sturgeon ( Acipenser fulvescens ) and examine how inbreeding depression may affect MVP. Our individual-based model incorporated inbreeding depression in two ways: individuals with inbreeding coefficients above a threshold experienced inbreeding depression (threshold), and individuals experienced inbreeding depression at a rate related to their inbreeding coefficient (gradual). Three mechanisms relating inbreeding to fitness were explored (young-of-the-year (YOY) viability, post-YOY viability, number of progeny). The criterion we used to determine MVP was a 5% chance of extinction over 250 years. The estimated MVP without inbreeding effects was 80 individuals. For some scenarios incorporating inbreeding, MVP did not change, but for others, MVP was substantially higher, reaching values up to 1800. Results demonstrate that extinction risk and MVP can be influenced by both demographic stochasticity and inbreeding depression. This research should inform management by determining MVP and how inbreeding, which is expected to accrue in remnant populations because of generations of low abundance, may affect MVP.

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