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Diamond SE, Martin RA, Bellino G, Crown KN, Prileson EG. Urban evolution of thermal physiology in a range-expanding, mycophagous fruit fly, Drosophila tripunctata. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
In Drosophila spp., their often high number of annual generations, large population sizes and large amounts of standing genetic variation should predispose them to undergo contemporary adaptation to climatic warming. However, a number of laboratory experimental evolution studies in this group of organisms suggest strong limits on the rate and magnitude of contemporary thermal adaptation. Here, we explore this discrepancy by examining the potential for rapid evolutionary divergence between wild populations of Drosophila tripunctata Loew, 1862 from rural and urban sites. We performed a multi-generation common garden study and found evidence for the evolution of higher heat tolerance (critical thermal maximum) in flies from urban populations. We also detected evolutionary divergence in cold resistance (chill coma recovery time), with diminished cold resistance in flies from urban populations, although the effect was weaker than the shift in heat tolerance. Our study provides evidence of contemporary urban thermal adaptation, although the magnitude of phenotypic change lagged the magnitude of environmental temperature change across the urbanization gradient, suggesting potential limits on the evolution of urban thermal physiology.
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Affiliation(s)
- Sarah E Diamond
- Department of Biology, Case Western Reserve University , Cleveland, OH 44106 , USA
| | - Ryan A Martin
- Department of Biology, Case Western Reserve University , Cleveland, OH 44106 , USA
| | - Grace Bellino
- Department of Biology, Case Western Reserve University , Cleveland, OH 44106 , USA
| | - K Nicole Crown
- Department of Biology, Case Western Reserve University , Cleveland, OH 44106 , USA
| | - Eric G Prileson
- Department of Biology, Case Western Reserve University , Cleveland, OH 44106 , USA
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2
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Jørgensen DB, Ørsted M, Kristensen TN. Sustained positive consequences of genetic rescue of fitness and behavioural traits in inbred populations of Drosophila melanogaster. J Evol Biol 2022; 35:868-878. [PMID: 35532930 PMCID: PMC9325394 DOI: 10.1111/jeb.14015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 04/10/2022] [Accepted: 04/12/2022] [Indexed: 11/30/2022]
Abstract
One solution to alleviate the detrimental genetic effects associated with reductions in population size and fragmentation is to introduce immigrants from other populations. While the effects of this genetic rescue on fitness traits are fairly well known, it is less clear to what extent inbreeding depression and subsequent genetic rescue affect behavioural traits. In this study, replicated crosses between inbred lines of Drosophila melanogaster were performed in order to investigate the effects of inbreeding and genetic rescue on egg-to-adult viability and negative geotaxis behaviour-a locomotor response used to measure, e.g. the effects of physiological ageing. Transgenerational effects of outcrossing were investigated by examining the fitness consequences in both the F1 and F4 generation. The majority of inbred lines showed evidence for inbreeding depression for both egg-to-adult viability and behavioural performance (95% and 66% of lines, respectively), with inbreeding depression being more pronounced for viability compared with the locomotor response. Subsequent outcrossing with immigrants led to an alleviation of the negative effects for both viability and geotaxis response resulting in inbred lines being similar to the outbred controls, with beneficial effects persisting from F1 to F4 . Overall, the results clearly show that genetic rescue can provide transgenerational rescue of small, inbred populations by rapidly improving population fitness components. Thus, we show that even the negative effects of inbreeding on behaviour, similar to that of neurodegeneration associated with physiological ageing, can be reversed by genetic rescue.
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Affiliation(s)
| | - Michael Ørsted
- Department of Chemistry and Bioscience, Aalborg University, Aalborg E, Denmark.,Department of Biology, Aarhus University, Aarhus C, Denmark
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Detecting purging of inbreeding depression by a slow rate of inbreeding for various traits: the impact of environmental and experimental conditions. Heredity (Edinb) 2021; 127:10-20. [PMID: 33903740 PMCID: PMC8249611 DOI: 10.1038/s41437-021-00436-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 04/08/2021] [Accepted: 04/08/2021] [Indexed: 02/02/2023] Open
Abstract
Inbreeding depression (ID) has since long been recognized as a significant factor in evolutionary biology. It is mainly the consequence of (partially) recessive deleterious mutations maintained by mutation-selection balance in large random mating populations. When population size is reduced, recessive alleles are increasingly found in homozygous condition due to drift and inbreeding and become more prone to selection. Particularly at slow rates of drift and inbreeding, selection will be more effective in purging such alleles, thereby reducing the amount of ID. Here we test assumptions of the efficiency of purging in relation to the inbreeding rate and the experimental conditions for four traits in D. melanogaster. We investigated the magnitude of ID for lines that were inbred to a similar level, F ≈ 0.50, reached either by three generations of full-sib mating (fast inbreeding), or by 12 consecutive generations with a small population size (slow inbreeding). This was done on two different food media. We observed significant ID for egg-to-adult viability and heat shock mortality, but only for egg-to-adult viability a significant part of the expressed inbreeding depression was effectively purged under slow inbreeding. For other traits like developmental time and starvation resistance, however, adaptation to the experimental and environmental conditions during inbreeding might affect the likelihood of purging to occur or being detected. We discuss factors that can affect the efficiency of purging and why empirical evidence for purging may be ambiguous.
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4
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Jensen C, Ørsted M, Kristensen TN. Effects of genetic distance on heterosis in a Drosophila melanogaster model system. Genetica 2018; 146:345-359. [PMID: 29761415 DOI: 10.1007/s10709-018-0026-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 05/08/2018] [Indexed: 11/27/2022]
Abstract
Habitat fragmentation and small population sizes can lead to inbreeding and loss of genetic variation, which can potentially cause inbreeding depression and decrease the ability of populations to adapt to altered environmental conditions. One solution to these genetic problems is the implementation of genetic rescue, which re-establishes gene flow between separated populations. Similar techniques are being used in animal and plant breeding to produce superior production animals and plants. To optimize fitness benefits in genetic rescue programs and to secure high yielding domestic varieties in animal and plant breeding, knowledge on the genetic relatedness of populations being crossed is imperative. In this study, we conducted replicated crosses between isogenic Drosophila melanogaster lines from the Drosophila Genetic Reference Panel. We grouped lines in two genetic distance groups to study the effect of genetic divergence between populations on the expression of heterosis in two fitness components; starvation resistance and reproductive output. We further investigated the transgenerational effects of outcrossing by investigating the fitness consequences in both the F1- and the F3-generations. High fitness enhancements were observed in hybrid offspring compared to parental lines, especially for reproductive output. However, the level of heterosis declined from the F1- to the F3-generation. Generally, genetic distance did not have strong impact on the level of heterosis detected, although there were exceptions to this pattern. The best predictor of heterosis was performance of parental lines with poorly performing parental lines showing higher hybrid vigour when crossed, i.e. the potential for heterosis was proportional to the level of inbreeding depression. Overall, our results show that outcrossing can have very strong positive fitness consequences for genetically depauperate populations.
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Affiliation(s)
- Charlotte Jensen
- Section of Biology and Environmental Science, Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220, Aalborg E, Denmark
| | - Michael Ørsted
- Section of Biology and Environmental Science, Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220, Aalborg E, Denmark.
| | - Torsten Nygaard Kristensen
- Section of Biology and Environmental Science, Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220, Aalborg E, Denmark.,Section of Genetics, Ecology and Evolution, Institute of Bioscience, Aarhus University, Ny Munkegade 114, 8000, Aarhus C, Denmark
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5
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Rosche C, Hensen I, Lachmuth S. Local pre-adaptation to disturbance and inbreeding-environment interactions affect colonisation abilities of diploid and tetraploid Centaurea stoebe. PLANT BIOLOGY (STUTTGART, GERMANY) 2018; 20:75-84. [PMID: 28921779 DOI: 10.1111/plb.12628] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 09/13/2017] [Indexed: 05/28/2023]
Abstract
Primary colonisation in invasive ranges most commonly occurs in disturbed habitats, where anthropogenic disturbance may cause physical damage to plants. The tolerance to such damage may differ between cytotypes and among populations as a result of differing population histories (adaptive differentiation between ruderal verus natural habitats). Moreover, founder populations often experience inbreeding depression, the effects of which may increase through physical damage due to inbreeding-environment interactions. We aimed to understand how such colonisation processes differ between diploid and tetraploid Centaurea stoebe populations, with a view to understanding why only tetraploids are invasive. We conducted a clipping experiment (frequency: zero, once or twice in the growing season) on inbred versus outbred offspring originating from 37 C. stoebe populations of varying cytotype, range and habitat type (natural versus ruderal). Aboveground biomass was harvested at the end of the vegetation period, while re-sprouting success was recorded in the following spring. Clipping reduced re-sprouting success and biomass, which was significantly more pronounced in natural than in ruderal populations. Inbreeding depression was not detected under benign conditions, but became increasingly apparent in biomass when plants were clipped. The effects of clipping and inbreeding did not differ between cytotypes. Adaptive differentiation in disturbance tolerance was higher among populations than between cytotypes, which highlights the potential of pre-adaptation in ruderal populations during early colonisation on anthropogenically disturbed sites. While the consequences of inbreeding increased through clipping-mediated stress, they were comparable between cytotypes, and consequently do not contribute to understanding the cytotype shift in the invasive range.
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Affiliation(s)
- C Rosche
- Institute of Biology/Geobotany and Botanical Garden, Martin Luther University Halle-Wittenberg, Halle, Germany
- UfU - Independent Institute for Environmental Issues, Berlin, Germany
| | - I Hensen
- Institute of Biology/Geobotany and Botanical Garden, Martin Luther University Halle-Wittenberg, Halle, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - S Lachmuth
- Institute of Biology/Geobotany and Botanical Garden, Martin Luther University Halle-Wittenberg, Halle, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
- Department of Plant Biology, University of Vermont, Burlington, VT, USA
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6
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Kristensen TN, Henningsen AK, Aastrup C, Bech-Hansen M, Bjerre LBH, Carlsen B, Hagstrup M, Jensen SG, Karlsen P, Kristensen L, Lundsgaard C, Møller T, Nielsen LD, Starcke C, Sørensen CR, Schou MF. Fitness components of Drosophila melanogaster developed on a standard laboratory diet or a typical natural food source. INSECT SCIENCE 2016; 23:771-779. [PMID: 25989059 DOI: 10.1111/1744-7917.12239] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/27/2015] [Indexed: 06/04/2023]
Abstract
Drosophila melanogaster is often used as a model organism in evolutionary biology and ecophysiology to study evolutionary processes and their physiological mechanisms. Diets used to feed Drosophila cultures differ between laboratories and are often nutritious and distinct from food sources in the natural habitat. Here we rear D. melanogaster on a standard diet used in our laboratory and a field diet composed of decomposing apples collected in the field. Flies developed on these two diet compositions are tested for heat, cold, desiccation, and starvation resistance as well as developmental time, dry body mass and fat percentage. The nutritional compositions of the standard and field diets were analyzed, and discussed in relation to the phenotypic observations. Results showed marked differences in phenotype of flies from the two types of diets. Flies reared on the field diet are more starvation resistant and they are smaller, leaner, and have lower heat resistance compared to flies reared on the standard diet. Sex specific effects of diet type are observed for several of the investigated traits and the strong sexual dimorphism usually observed in desiccation resistance in D. melanogaster disappeared when rearing the flies on the field diet. Based on our results we conclude that care should be taken in extrapolating results from one type of diet to another and especially from laboratory to field diets.
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Affiliation(s)
- Torsten Nygaard Kristensen
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Aalborg East, DK-9220, Denmark.
| | - Astrid Kallestrup Henningsen
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Aalborg East, DK-9220, Denmark
| | - Christian Aastrup
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Aalborg East, DK-9220, Denmark
| | - Mads Bech-Hansen
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Aalborg East, DK-9220, Denmark
| | - Lise B Hoberg Bjerre
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Aalborg East, DK-9220, Denmark
| | - Benjamin Carlsen
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Aalborg East, DK-9220, Denmark
| | - Marie Hagstrup
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Aalborg East, DK-9220, Denmark
| | - Sofie Graarup Jensen
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Aalborg East, DK-9220, Denmark
| | - Pernille Karlsen
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Aalborg East, DK-9220, Denmark
| | - Line Kristensen
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Aalborg East, DK-9220, Denmark
| | - Cecillie Lundsgaard
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Aalborg East, DK-9220, Denmark
| | - Tine Møller
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Aalborg East, DK-9220, Denmark
| | - Lise D Nielsen
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Aalborg East, DK-9220, Denmark
| | - Camilla Starcke
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Aalborg East, DK-9220, Denmark
| | - Christine Riisager Sørensen
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Aalborg East, DK-9220, Denmark
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7
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Kristensen TN, Hoffmann AA, Pertoldi C, Stronen AV. What can livestock breeders learn from conservation genetics and vice versa? Front Genet 2015; 6:38. [PMID: 25713584 PMCID: PMC4322732 DOI: 10.3389/fgene.2015.00038] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 01/26/2015] [Indexed: 11/17/2022] Open
Abstract
The management of livestock breeds and threatened natural population share common challenges, including small effective population sizes, high risk of inbreeding, and the potential benefits and costs associated with mixing disparate gene pools. Here, we consider what has been learnt about these issues, the ways in which the knowledge gained from one area might be applied to the other, and the potential of genomics to provide new insights. Although there are key differences stemming from the importance of artificial versus natural selection and the decreased level of environmental heterogeneity experienced by many livestock populations, we suspect that information from genetic rescue in natural populations could be usefully applied to livestock. This includes an increased emphasis on maintaining substantial population sizes at the expense of genetic uniqueness in ensuring future adaptability, and on emphasizing the way that environmental changes can influence the relative fitness of deleterious alleles and genotypes in small populations. We also suspect that information gained from cross-breeding and the maintenance of unique breeds will be increasingly important for the preservation of genetic variation in small natural populations. In particular, selected genes identified in domestic populations provide genetic markers for exploring adaptive evolution in threatened natural populations. Genomic technologies in the two disciplines will be important in the future in realizing genetic gains in livestock and maximizing adaptive capacity in wildlife, and particularly in understanding how parts of the genome may respond differently when exposed to population processes and selection.
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Affiliation(s)
- Torsten N. Kristensen
- Section of Biology and Environmental Science, Department of Chemistry and Bioscience, Aalborg UniversityAalborg, Denmark
| | - Ary A. Hoffmann
- Department of Zoology and Department of Genetics, Bio21 Institute, The University of MelbourneMelbourne, VIC, Australia
| | - Cino Pertoldi
- Section of Biology and Environmental Science, Department of Chemistry and Bioscience, Aalborg UniversityAalborg, Denmark
- Aalborg ZooAalborg, Denmark
| | - Astrid V. Stronen
- Section of Biology and Environmental Science, Department of Chemistry and Bioscience, Aalborg UniversityAalborg, Denmark
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8
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Lanzavecchia SB, Juri M, Bonomi A, Gomulski L, Scannapieco AC, Segura DF, Malacrida A, Cladera JL, Gasperi G. Microsatellite markers from the 'South American fruit fly' Anastrepha fraterculus: a valuable tool for population genetic analysis and SIT applications. BMC Genet 2014; 15 Suppl 2:S13. [PMID: 25471285 PMCID: PMC4255783 DOI: 10.1186/1471-2156-15-s2-s13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background Anastrepha fraterculus Wiedemann is a horticultural pest which causes significant economic losses in the fruit-producing areas of the American continent and limits the access of products to international markets. The use of environmentally friendly control strategies against this pest is constrained due to the limited knowledge of its population structure. Results We developed microsatellite markers for A. fraterculus from four genomic libraries, which were enriched in CA, CAA, GA and CAT microsatellite motifs. Fifty microsatellite regions were evaluated and 14 loci were selected for population genetics studies. Genotypes of 122 individuals sampled from four A. fraterculus populations were analyzed. The level of polymorphism ranged from three to 13 alleles per locus and the mean expected heterozygosity ranged from 0.60 to 0.64. Comparison between allelic and genotypic frequencies showed significant differences among all pairs of populations. Conclusions This novel set of microsatellite markers provides valuable information for the description of genetic variability and population structure of wild populations and laboratory strains of A. fraterculus. This information will be used to identify and characterize candidate strains suitable to implement effective pest control strategies and might represent a first step towards having a more comprehensive knowledge about the genetics of this pest.
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Vermeulen CJ, Sørensen P, Gagalova KK, Loeschcke V. Flies who cannot take the heat: genome-wide gene expression analysis of temperature-sensitive lethality in an inbred line of Drosophila melanogaster. J Evol Biol 2014; 27:2152-62. [PMID: 25233925 DOI: 10.1111/jeb.12472] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/16/2014] [Accepted: 07/22/2014] [Indexed: 11/29/2022]
Abstract
Fitness decreases associated with inbreeding depression often become more pronounced in a stressful environment. The functional genomic causes of these inbreeding-by-environment (I × E) interactions, and of inbreeding depression in general, are poorly known. To further our understanding of I × E interactions, we performed a genome-wide gene expression study of a single inbred line that suffers from temperature-sensitive lethality. We confirmed that increased differential expression between the thermosensitive line and the control line occurs at the restrictive temperature. This demonstrates that I × E interactions in survival are reflected in similar I × E interactions at the gene expression level. To make an impression of the cellular response associated with the lethal effect, we analysed all functional annotation terms that were overrepresented among the differentially expressed genes. Some sets of differentially expressed genes function in the general stress response, and these are more likely to also be differentially expressed in other studies of inbreeding, inbreeding depression, immunity and heat stress. Other sets of differentially expressed genes are shared with studies of gene expression in inbred lines, but not studies of the response to extrinsic stress, and represent a general transcriptomic signature of inbreeding. Finally, some sets of genes have an annotation that is not reported in other studies. These we consider to be candidates for the genes harbouring the mutations responsible for the thermosensitive phenotype, as these mutations are expected to be unique to this line. These genes may also serve as candidate QTL in studies of thermal tolerance and heat resistance.
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Affiliation(s)
- C J Vermeulen
- Genetics, Ecology and Evolution, Department of Bioscience, Aarhus University, Aarhus C, Denmark; Evolutionary Genetics, Centre for Ecological and Evolutionary Studies, University of Groningen, Groningen, The Netherlands
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10
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Franke K, Fischer K. Inbreeding interferes with the heat-shock response. Heredity (Edinb) 2014; 114:80-4. [PMID: 25074571 DOI: 10.1038/hdy.2014.72] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 05/26/2014] [Accepted: 06/04/2014] [Indexed: 11/09/2022] Open
Abstract
Inbreeding is typically detrimental to individual fitness, with negative effects being often exaggerated in stressful environments. However, the causal mechanisms underlying inbreeding depression in general and the often increased susceptibility to stress in particular are not well understood. We here test whether inbreeding interferes with the heat-shock response, comprising an important component of the stress response which may therefore underscore sensitivity to stress. To this end we subjected the tropical butterfly Bicyclus anynana to a full-factorial design with three temperatures and three levels of inbreeding, and measured the expression of heat-shock protein (HSP) 70 via qPCR. HSP70 expression increased after exposure to heat as compared with cold or control conditions. Most strikingly, inbreeding strongly interfered with the heat-shock response, with inbred individuals showing a very weak upregulation of HSP70 only. Our results thus indicate that, in our study organism, interference with the heat-shock response may be one mechanism underlying reduced fitness of inbred individuals, especially when exposed to stressful conditions. However, these indications need to be corroborated using a broader range of different temperatures, genes and taxa.
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Affiliation(s)
- Kristin Franke
- Zoological Institute and Museum, University of Greifswald, Greifswald, Germany
| | - Klaus Fischer
- Zoological Institute and Museum, University of Greifswald, Greifswald, Germany
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11
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Jensen P, Overgaard J, Loeschcke V, Schou MF, Malte H, Kristensen TN. Inbreeding effects on standard metabolic rate investigated at cold, benign and hot temperatures in Drosophila melanogaster. JOURNAL OF INSECT PHYSIOLOGY 2014; 62:11-20. [PMID: 24456661 DOI: 10.1016/j.jinsphys.2014.01.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 12/23/2013] [Accepted: 01/09/2014] [Indexed: 06/03/2023]
Abstract
Inbreeding increases homozygosity, which is known to affect the mean and variance of fitness components such as growth, fecundity and mortality rate. Across inbred lines inbreeding depression is typically observed and the variance between lines is increased in inbred compared to outbred lines. It has been suggested that damage incurred from increased homozygosity entails energetic cost associated with cellular repair. However, little is known about the effects of inbreeding on standard metabolic rate. Using stop-flow respirometry we performed repeated measurements of metabolic rate in replicated lines of inbred and outbred Drosophila melanogaster at stressful low, benign and stressful high temperatures. The lowest measurements of metabolic rate in our study are always associated with the low activity period of the diurnal cycle and these measurements therefore serve as good estimates of standard metabolic rate. Due to the potentially added costs of genetic stress in inbred lines we hypothesized that inbred individuals have increased metabolic rate compared to outbred controls and that this is more pronounced at stressful temperatures due to synergistic inbreeding by environment interactions. Contrary to our hypothesis we found no significant difference in metabolic rate between inbred and outbred lines and no interaction between inbreeding and temperature. Inbreeding however effected the variance; the variance in metabolic rate was higher between the inbred lines compared to the outbred control lines with some inbred lines having very high or low standard metabolic rate. Thus genetic drift and not inbreeding per se seem to explain variation in metabolic rate in populations of different size.
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Affiliation(s)
- Palle Jensen
- Department of Bioscience, Aarhus University, Ny Munkegade 116, DK-8000 Aarhus C, Denmark; Department of Molecular Biology and Genetics, Aarhus University, Blichers Allé 20, DK-8830 Tjele, Denmark.
| | - Johannes Overgaard
- Department of Bioscience, Aarhus University, Ny Munkegade 116, DK-8000 Aarhus C, Denmark
| | - Volker Loeschcke
- Department of Bioscience, Aarhus University, Ny Munkegade 116, DK-8000 Aarhus C, Denmark
| | - Mads Fristrup Schou
- Department of Bioscience, Aarhus University, Ny Munkegade 116, DK-8000 Aarhus C, Denmark
| | - Hans Malte
- Department of Bioscience, Aarhus University, Ny Munkegade 116, DK-8000 Aarhus C, Denmark
| | - Torsten Nygaard Kristensen
- Department of Biotechnology, Chemistry and Environmental Engineering, Section of Biology and Environmental Science, Aalborg University, Sohngaardsholmsvej 57, DK-9000 Aalborg, Denmark
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12
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Pekkala N, Knott KE, Kotiaho JS, Nissinen K, Puurtinen M. The effect of inbreeding rate on fitness, inbreeding depression and heterosis over a range of inbreeding coefficients. Evol Appl 2014; 7:1107-19. [PMID: 25553071 PMCID: PMC4231599 DOI: 10.1111/eva.12145] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 12/20/2013] [Indexed: 11/28/2022] Open
Abstract
Understanding the effects of inbreeding and genetic drift within populations and hybridization between genetically differentiated populations is important for many basic and applied questions in ecology and evolutionary biology. The magnitudes and even the directions of these effects can be influenced by various factors, especially by the current and historical population size (i.e. inbreeding rate). Using Drosophila littoralis as a model species, we studied the effect of inbreeding rate over a range of inbreeding levels on (i) mean fitness of a population (relative to that of an outbred control population), (ii) within-population inbreeding depression (reduction in fitness of offspring from inbred versus random mating within a population) and (iii) heterosis (increase in fitness of offspring from interpopulation versus within-population random mating). Inbreeding rate was manipulated by using three population sizes (2, 10 and 40), and fitness was measured as offspring survival and fecundity. Fast inbreeding (smaller effective population size) resulted in greater reduction in population mean fitness than slow inbreeding, when populations were compared over similar inbreeding coefficients. Correspondingly, populations with faster inbreeding expressed more heterosis upon interpopulation hybridization. Inbreeding depression within the populations did not have a clear relationship with either the rate or the level of inbreeding.
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Affiliation(s)
- Nina Pekkala
- Department of Biological and Environmental Science, University of Jyväskylä Jyväskylä, Finland
| | - K Emily Knott
- Department of Biological and Environmental Science, University of Jyväskylä Jyväskylä, Finland
| | - Janne S Kotiaho
- Department of Biological and Environmental Science, University of Jyväskylä Jyväskylä, Finland ; Natural History Museum, University of Jyväskylä Jyväskylä, Finland
| | - Kari Nissinen
- Finnish Institute for Educational Research, University of Jyväskylä Jyväskylä, Finland
| | - Mikael Puurtinen
- Department of Biological and Environmental Science, University of Jyväskylä Jyväskylä, Finland ; Centre of Excellence in Biological Interactions, University of Jyväskylä Jyväskylä, Finland
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13
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Vermeulen CJ, Sørensen P, Kirilova Gagalova K, Loeschcke V. Transcriptomic analysis of inbreeding depression in cold-sensitive Drosophila melanogaster
shows upregulation of the immune response. J Evol Biol 2013; 26:1890-902. [DOI: 10.1111/jeb.12183] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 04/08/2013] [Accepted: 04/09/2013] [Indexed: 11/28/2022]
Affiliation(s)
- C. J. Vermeulen
- Ecology and Genetics; Department of Biological Sciences; Aarhus University; Aarhus C Denmark
- Evolutionary Genetics; Centre for Ecological and Evolutionary Studies; University of Groningen; Groningen The Netherlands
| | - P. Sørensen
- Department of Genetics and Biotechnology; Danish Institute of Agricultural Sciences; Aarhus University; Tjele Denmark
| | - K. Kirilova Gagalova
- Evolutionary Genetics; Centre for Ecological and Evolutionary Studies; University of Groningen; Groningen The Netherlands
- Department of Pharmacy and BioTechnology; University of Bologna; Bologna Italy
| | - V. Loeschcke
- Ecology and Genetics; Department of Biological Sciences; Aarhus University; Aarhus C Denmark
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14
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Bilski DR, Pie MR, Passos FC. Variable inbreeding effects across life-history stages in a captive carnivorous mammal population. Anim Conserv 2013. [DOI: 10.1111/acv.12038] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- D. R. Bilski
- Programa de Pós-Graduação em Ecologia e Conservação; Universidade Federal do Paraná; Curitiba PR Brazil
| | - M. R. Pie
- Departamento de Zoologia; Universidade Federal do Paraná; Curitiba PR Brazil
| | - F. C. Passos
- Departamento de Zoologia; Universidade Federal do Paraná; Curitiba PR Brazil
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15
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Franke K, Fischer K. Effects of inbreeding and temperature stress on life history and immune function in a butterfly. J Evol Biol 2013; 26:517-28. [PMID: 23286274 DOI: 10.1111/jeb.12064] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 10/30/2012] [Accepted: 10/31/2012] [Indexed: 11/30/2022]
Affiliation(s)
- K. Franke
- Zoological Institute and Museum; University of Greifswald; Greifswald Germany
| | - K. Fischer
- Zoological Institute and Museum; University of Greifswald; Greifswald Germany
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16
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Mattila ALK, Duplouy A, Kirjokangas M, Lehtonen R, Rastas P, Hanski I. High genetic load in an old isolated butterfly population. Proc Natl Acad Sci U S A 2012; 109:E2496-505. [PMID: 22908265 PMCID: PMC3443129 DOI: 10.1073/pnas.1205789109] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We investigated inbreeding depression and genetic load in a small (N(e) ∼ 100) population of the Glanville fritillary butterfly (Melitaea cinxia), which has been completely isolated on a small island [Pikku Tytärsaari (PT)] in the Baltic Sea for at least 75 y. As a reference, we studied conspecific populations from the well-studied metapopulation in the Åland Islands (ÅL), 400 km away. A large population in Saaremaa, Estonia, was used as a reference for estimating genetic diversity and N(e). We investigated 58 traits related to behavior, development, morphology, reproductive performance, and metabolism. The PT population exhibited high genetic load (L = 1 - W(PT)/W(ÅL)) in a range of fitness-related traits including adult weight (L = 0.12), flight metabolic rate (L = 0.53), egg viability (L = 0.37), and lifetime production of eggs in an outdoor population cage (L = 0.70). These results imply extensive fixation of deleterious recessive mutations, supported by greatly reduced diversity in microsatellite markers and immediate recovery (heterosis) of egg viability and flight metabolic rate in crosses with other populations. There was no significant inbreeding depression in most traits due to one generation of full-sib mating. Resting metabolic rate was significantly elevated in PT males, which may be related to their short lifespan (L = 0.25). The demographic history and the effective size of the PT population place it in the part of the parameter space in which models predict mutation accumulation. This population exemplifies the increasingly common situation in fragmented landscapes, in which small and completely isolated populations are vulnerable to extinction due to high genetic load.
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Affiliation(s)
- Anniina L. K. Mattila
- Metapopulation Research Group, Department of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland
| | - Anne Duplouy
- Metapopulation Research Group, Department of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland
| | - Malla Kirjokangas
- Metapopulation Research Group, Department of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland
| | - Rainer Lehtonen
- Metapopulation Research Group, Department of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland
| | - Pasi Rastas
- Metapopulation Research Group, Department of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland
| | - Ilkka Hanski
- Metapopulation Research Group, Department of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland
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17
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Pekkala N, Emily Knott K, Kotiaho JS, Puurtinen M. Inbreeding rate modifies the dynamics of genetic load in small populations. Ecol Evol 2012; 2:1791-804. [PMID: 22957182 PMCID: PMC3433984 DOI: 10.1002/ece3.293] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 05/08/2012] [Accepted: 05/09/2012] [Indexed: 11/30/2022] Open
Abstract
The negative fitness consequences of close inbreeding are widely recognized, but predicting the long-term effects of inbreeding and genetic drift due to limited population size is not straightforward. As the frequency and homozygosity of recessive deleterious alleles increase, selection can remove (purge) them from a population, reducing the genetic load. At the same time, small population size relaxes selection against mildly harmful mutations, which may lead to accumulation of genetic load. The efficiency of purging and the accumulation of mutations both depend on the rate of inbreeding (i.e., population size) and on the nature of mutations. We studied how increasing levels of inbreeding affect offspring production and extinction in experimental Drosophila littoralis populations replicated in two sizes, N = 10 and N = 40. Offspring production and extinction were measured over 25 generations concurrently with a large control population. In the N = 10 populations, offspring production decreased strongly at low levels of inbreeding, then recovered only to show a consistent subsequent decline, suggesting early expression and purging of recessive highly deleterious alleles and subsequent accumulation of mildly harmful mutations. In the N = 40 populations, offspring production declined only after inbreeding reached higher levels, suggesting that inbreeding and genetic drift pose a smaller threat to population fitness when inbreeding is slow. Our results suggest that highly deleterious alleles can be purged in small populations already at low levels of inbreeding, but that purging does not protect the small populations from eventual genetic deterioration and extinction.
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Affiliation(s)
- Nina Pekkala
- Department of Biological and Environmental Science, University of JyväskyläFinland
| | - K Emily Knott
- Department of Biological and Environmental Science, University of JyväskyläFinland
| | - Janne S Kotiaho
- Department of Biological and Environmental Science, University of JyväskyläFinland
- Natural History Museum, University of JyväskyläFinland
| | - Mikael Puurtinen
- Department of Biological and Environmental Science, University of JyväskyläFinland
- Centre of Excellence in Biological Interactions, University of JyväskyläFinland
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18
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Enders LS, Nunney L. Seasonal stress drives predictable changes in inbreeding depression in field-tested captive populations of Drosophila melanogaster. Proc Biol Sci 2012; 279:3756-64. [PMID: 22719040 DOI: 10.1098/rspb.2012.1018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Recent meta-analyses conducted across a broad range of taxa have demonstrated a strong linear relationship between the change in magnitude of inbreeding depression under stress and stress level, measured as fitness loss in outbred individuals. This suggests that a general underlying response may link stress and inbreeding depression. However, this relationship is based primarily on laboratory data, and it is unknown whether natural environments with multiple stressors and fluctuating stress levels alter how stress affects inbreeding depression. To test whether the same pattern persists in the field, we investigated the effect of seasonal variation on stress level and inbreeding depression in a 3-year field study measuring the productivity of captive populations of inbred and outbred Drosophila melanogaster. We found cold winter temperatures were most stressful and induced the greatest inbreeding depression. Furthermore, these data, collected under natural field conditions, conformed to the same predictive linear relationship seen in Drosophila laboratory studies, with inbreeding depression increasing by 0.17 lethal equivalents for every 10 per cent increase in stress level. Our results suggest that under natural conditions stress level is a primary determinant of the magnitude of inbreeding depression and should be considered when assessing extinction vulnerability in small populations.
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Affiliation(s)
- Laramy S Enders
- Department of Biology, University of California, Riverside, CA 92507, USA.
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19
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Affiliation(s)
- Anneke Dierks
- Zoological Institute and Museum, University of Greifswald, J.-S.-Bachstraße 11/12, D-17489 Greifswald, Germany.
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20
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Dierks A, Hoffmann B, Bauerfeind SS, Fischer K. Effects of inbreeding on life history and thermal performance in the tropical butterfly Bicyclus anynana. POPUL ECOL 2011. [DOI: 10.1007/s10144-011-0291-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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21
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Willett CS. Hybrid breakdown weakens under thermal stress in population crosses of the copepod Tigriopus californicus. ACTA ACUST UNITED AC 2011; 103:103-14. [PMID: 22016434 DOI: 10.1093/jhered/esr109] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The outcome of hybridization can be impacted by environmental conditions, which themselves can contribute to reproductive isolation between taxa. In crosses of genetically divergent populations, hybridization can have both negative and positive impacts on fitness, the balance between which might be tipped by changes in the environment. Genetically divergent populations of the intertidal copepod Tigriopus californicus have been shown to differ in thermal tolerance at high temperatures along a latitudinal gradient. In this study, a series of crosses were made between pairs of genetically divergent populations of T. californicus, and the thermal tolerance of these hybrids was tested. In most cases, the first-generation hybrids had relatively high thermal tolerance and the second-generation hybrids were not generally reduced below the less-tolerant parental population for high temperature tolerance. This pattern contrasts with previous studies from crosses of genetically divergent populations of this copepod, which often shows hybrid breakdown in these second-generation hybrids for other measures of fitness. These results suggest that high temperature stress could either increase the positive impacts of hybridization or decrease the negative impacts of hybridization resulting in lowered hybrid breakdown in these population crosses.
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Affiliation(s)
- Christopher S Willett
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280, USA.
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22
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Analysis of the effects of inbreeding on lifespan and starvation resistance in Drosophila melanogaster. Genetica 2011; 139:525-33. [PMID: 21505760 DOI: 10.1007/s10709-011-9574-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Accepted: 04/02/2011] [Indexed: 10/18/2022]
Abstract
Because of their decreased overall fitness and genetic variability inbred individuals are expected to show reduced survival and lifespan under most environmental conditions as compared with outbred individuals. Whereas evidence for the deleterious effects of inbreeding on lifespan has been previously provided, only a few studies have investigated effects of inbreeding on survival under starved conditions. In the present study we compared the abilities of inbred and outbred adult Drosophila melanogaster to survive under starved and fed conditions. We found that inbreeding reduced lifespan but had no effect on starvation resistance. The results indicate highly trait specific consequences of inbreeding. Possible mechanisms behind the observed results are discussed.
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23
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Slow inbred lines of Drosophila melanogaster express as much inbreeding depression as fast inbred lines under semi-natural conditions. Genetica 2011; 139:441-51. [PMID: 21416261 DOI: 10.1007/s10709-011-9563-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 03/07/2011] [Indexed: 10/18/2022]
Abstract
Selection may reduce the deleterious consequences of inbreeding. This may be due to purging of recessive deleterious alleles or balancing selection favouring heterozygote offspring. Such selection is expected to be more efficient at slower compared to at faster rates of inbreeding. In this study we tested the impact of inbreeding and the rate of inbreeding on fitness related traits (egg productivity, egg-to-adult viability, developmental time and behaviour) under cold and benign semi-natural thermal conditions using Drosophila melanogaster as a model organism. We used non-inbred control and slow and fast inbred lines (both with an expected inbreeding level of 0.25). The results show that contrary to expectations the slow inbred lines do not maintain higher average fitness than the fast inbred lines. Furthermore, we found that stressful environmental conditions increased the level of inbreeding depression but the impact of inbreeding rate on the level of inbreeding depression was not affected by the environmental conditions. The results do not support the hypothesis that inbreeding depression is less severe with slow compared to fast rates of inbreeding and illustrate that although selection may be more efficient with slower rates of inbreeding this does not necessary lead to less inbreeding depression.
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