scholarly journals Distance between pollen donor and recipient influences fruiting success in slickspot peppergrass, Lepidium papilliferum

2004 ◽  
Vol 82 (12) ◽  
pp. 1705-1710 ◽  
Author(s):  
Ian C Robertson ◽  
Amy Colleen Ulappa
Keyword(s):  
Genetic Diversity ◽  
Spatial Structure ◽  
Inbreeding Depression ◽  
Reproductive Performance ◽  
Sagebrush Steppe ◽  
Suitable Habitat ◽  
Plant Populations ◽  
Pollen Donor ◽  
Hand Pollination ◽  
Limited Dispersal

Plant populations are often spatially structured owing to limited dispersal of pollen and seed. Mating between neighboring individuals in such populations often leads to reduced reproductive performance relative to matings between distant individuals. This response, which may be a result of inbreeding depression or prezygotic mating barriers, was investigated for slickspot peppergrass, Lepidium papilliferum L. (Brassicaceae), a rare insect-pollinated mustard endemic to sagebrush–steppe habitat in southwestern Idaho. Through hand pollination experiments we found that individual plants receiving pollen from distant sources (75–100 m and 6.5–20 km away) had significantly higher percent fruit sets than those relying on pollen from neighboring plants (<1 m away). Self pollinated plants produced little or no fruit. These results suggest that L. papilliferum relies primarily, if not exclusively, on outcrossed pollination, and that its populations are spatially structured. Conservation efforts should therefore strive to protect sufficiently large areas of suitable habitat to ensure maintenance of genetic diversity and preserve or enhance connectivity between populations.Key words: Brassicaceae, inbreeding, outbreeding, population spatial structure, rare species.

scholarly journals Spatial structure and inbreeding depression in slickspot peppergrass, Lepidium papilliferum (Brassicaceae)

Botany ◽  
2008 ◽  
Vol 86 (9) ◽  
pp. 1002-1008 ◽  
Author(s):  
Stephanie A. Billinge ◽  
Ian C. Robertson
Keyword(s):  
Spatial Structure ◽  
Inbreeding Depression ◽  
Reproductive Performance ◽  
Fruit Set ◽  
Leaf Length ◽  
Small Populations ◽  
Hand Pollination ◽  
Large Populations ◽  
Pollen And Seed Dispersal ◽  
Close Relatives

In plants with limited pollen and seed dispersal, populations are often spatially structured such that neighboring individuals are more closely related to one another than to distant individuals. Mating among close relatives, including selfing, may lead to a reduction in reproductive performance through the effects of prezygotic mating barriers and inbreeding depression. Studying 11 populations of slickspot peppergrass, Lepidium papilliferum (L.F. Hend.) A. Nels. and J.F. Macbr (Brassicaceae), a rare mustard endemic to southwestern Idaho, we investigated whether small populations (16–746 flowering individuals) exhibit spatial structure as previously reported for large populations (>3000 flowering individuals). Through hand-pollination experiments we found that percent fruit set increased with increasing distance between parents up to a distance of 3 m, and declined slightly but nonsignificantly at greater outcrossing distances. Self-pollinated plants produced little or no fruit. Germination of seeds from the hand-pollination experiment revealed signs of inbreeding depression in the offspring. Specifically, leaf length of developing seedlings increased significantly as a function of outcrossing distance. Total leaf number showed a similar, yet statistically nonsignificant, response to outcrossing distance. Overall, our experiments reveal spatial structuring and suggest the occurrence of inbreeding depression in small populations of L. papilliferum.

Inter-parent distance affects reproductive success in two clonal dwarf shrubs, Vaccinium myrtillus and Vaccinium vitis-idaea (Ericaceae)

2002 ◽  
Vol 80 (8) ◽  
pp. 875-884 ◽  
Author(s):  
Carolin Nuortila ◽  
Juha Tuomi ◽  
Kari Laine
Keyword(s):  
Reproductive Success ◽  
Natural Populations ◽  
Vaccinium Myrtillus ◽  
Seed Number ◽  
Genetic Population ◽  
Pollen Donor ◽  
Hand Pollination ◽  
Population Structures ◽  
Limited Dispersal ◽  
Vaccinium Myrtillus L

Clonal propagation and limited dispersal of seeds lead to genetic population structures in which most potential mates are relatives. If the species suffers from inbreeding depression or is self-incompatible, the number of seeds matured per fruit may be limited by the lack of outcrossing by unrelated pollen. We tested for distance-related genetic structure by hand-pollinating plants at increasing distances and measuring fruit set (berries/pollinated flowers) and seed number per fruit in natural populations of bilberry (Vaccinium myrtillus L.) and lingonberry (Vaccinium vitis-idaea L.). Bagging of the flower buds without natural (pollination by insects) or hand-pollination yielded almost no fruit or seed, suggesting that the species are obligately insect pollinated. Self-pollination led to a significant reduction in seed number per fruit and increased seed abortion compared with cross-pollination. Moreover, seed number increased with increasing distance between the pollen donor and pollen recipient. Flight distances of bumblebees were estimated for bilberry by monitoring between-flower and, for lingonberry, between-inflorescence flight distances. About 90% of all flights were at distances of less than 1 m. At this distance, we observed less than the maximum seed number per fruit in hand-pollinations in both study species. Consequently, clonal growth is likely to be an important factor that constrains fruit and seed number in these species.Key words: bumblebee forage distance, clonal, hand-pollination, inter-parent distance, reproductive success, Vaccinium.

scholarly journals Minimal loss of genetic diversity and no inbreeding depression in blueflag iris (Iris versicolor) on islands in the Bay of Fundy

Botany ◽  
2016 ◽  
Vol 94 (7) ◽  
pp. 543-554 ◽  
Author(s):  
Nathaniel T. Wheelwright ◽  
Elise Begin ◽  
Claire Ellwanger ◽  
Samuel H. Taylor ◽  
Judy L. Stone
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Inbreeding Depression ◽  
Leaf Tissue ◽  
Population Level ◽  
Bay Of Fundy ◽  
Isolated Populations ◽  
Tissue Samples ◽  
Island Populations ◽  
Hand Pollination

Isolated island plant populations founded by few individuals are often characterized by decreased genetic variation and increased inbreeding. Our aim was to measure population genetic diversity and inbreeding depression in blueflag iris (Iris versicolor L., Iridaceae), a native allotetraploid, on islands in the Bay of Fundy, Canada. Hand-pollination experiments (inbreeding, within-site outbreeding, between-island outbreeding) on Kent Island, New Brunswick, revealed no evidence for inbreeding depression across a broad array of morphological, physiological, and life-history traits. Leaf tissue samples collected from three mainland sites and 10 islands in the Bay of Fundy and genotyped using three microsatellite primer pairs showed that island populations were less genetically diverse than mainland populations. Island populations were genetically distinct from each other, indicating a bottleneck effect associated with colonization and continued isolation. Nonetheless, substantial genetic variation was maintained at the population level. Polyploidy and a history of self-fertilization may allow Iris versicolor to avoid inbreeding depression in isolated populations. Our study supports Anderson’s (1936) original hypothesis that substantial genetic diversity can be preserved within polyploid species, even with extensive inbreeding.

scholarly journals Trends in genetic diversity and the effect of inbreeding in American Angus cattle under genomic selection

2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Emmanuel A. Lozada-Soto ◽  
Christian Maltecca ◽  
Duc Lu ◽  
Stephen Miller ◽  
John B. Cole ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Beef Cattle ◽  
Genomic Selection ◽  
Inbreeding Depression ◽  
Growth Traits ◽  
Effective Population ◽  
Angus Cattle ◽  
Genomic Inbreeding ◽  
Chromosome Segments ◽  
The Impact

Abstract Background While the adoption of genomic evaluations in livestock has increased genetic gain rates, its effects on genetic diversity and accumulation of inbreeding have raised concerns in cattle populations. Increased inbreeding may affect fitness and decrease the mean performance for economically important traits, such as fertility and growth in beef cattle, with the age of inbreeding having a possible effect on the magnitude of inbreeding depression. The purpose of this study was to determine changes in genetic diversity as a result of the implementation of genomic selection in Angus cattle and quantify potential inbreeding depression effects of total pedigree and genomic inbreeding, and also to investigate the impact of recent and ancient inbreeding. Results We found that the yearly rate of inbreeding accumulation remained similar in sires and decreased significantly in dams since the implementation of genomic selection. Other measures such as effective population size and the effective number of chromosome segments show little evidence of a detrimental effect of using genomic selection strategies on the genetic diversity of beef cattle. We also quantified pedigree and genomic inbreeding depression for fertility and growth. While inbreeding did not affect fertility, an increase in pedigree or genomic inbreeding was associated with decreased birth weight, weaning weight, and post-weaning gain in both sexes. We also measured the impact of the age of inbreeding and found that recent inbreeding had a larger depressive effect on growth than ancient inbreeding. Conclusions In this study, we sought to quantify and understand the possible consequences of genomic selection on the genetic diversity of American Angus cattle. In both sires and dams, we found that, generally, genomic selection resulted in decreased rates of pedigree and genomic inbreeding accumulation and increased or sustained effective population sizes and number of independently segregating chromosome segments. We also found significant depressive effects of inbreeding accumulation on economically important growth traits, particularly with genomic and recent inbreeding.

scholarly journals Genetic melting pot and importance of long-distance dispersal indicated in the Gladiolus imbricatus L. populations in the Polish Carpathians

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Agnieszka Sutkowska ◽  
Józef Mitka ◽  
Tomasz Warzecha ◽  
Jakub Bunk ◽  
Julia Rutkowska ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Diversity Indices ◽  
Western Carpathians ◽  
Genetic Structuring ◽  
Long Distance ◽  
Plant Populations ◽  
Genetic Stock ◽  
Melting Pot ◽  
Mountain Ranges ◽  
Eastern Carpathians

AbstractThe genetic diversity in 11 populations of Gladiolus imbricatus in five mountain ranges, including the Tatra, Pieniny, Gorce, Beskid Niski (Western Carpathians) and Bieszczady Mts (Eastern Carpathians), was studied with inter-simple sequence repeat (ISSR) markers. The species is a perennial plant occurring in open and semi-open sites of anthropogenic origin (meadows and forest margins). We checked a hypothesis on the microrefugial character of the plant populations in the Pieniny Mts, a small calcareous Carpathian range of complicated relief that has never been glaciated. Plant populations in the Tatra and Pieniny Mts had the highest genetic diversity indices, pointing to their long-term persistence. The refugial vs. the non-refugial mountain ranges accounted for a relatively high value of total genetic variation [analysis of molecular variance (AMOVA), 14.12%, p = 0.003]. One of the Pieniny populations was of hybridogenous origin and shared genetic stock with the Tatra population, indicating there is a local genetic melting pot. A weak genetic structuring of populations among particular regions was found (AMOVA, 4.5%, p > 0.05). This could be an effect of the frequent short-distance and sporadic long-distance gene flow. The dispersal of diaspores between the remote populations in the Western Carpathians and Eastern Carpathians could be affected by the historical transportation of flocks of sheep from the Tatra to Bieszczady Mts.

scholarly journals Spatial structure of Eugenia dysenterica based on essential oil chemovariations and implications for conservation and management of the genetic diversity of its populations

2012 ◽  
Vol 23 (10) ◽  
pp. 1776-1782 ◽  
Author(s):  
Eliane C. Vilela ◽  
Thays C. Carvalho ◽  
Alessandra R. Duarte ◽  
Ronaldo R. Naves ◽  
Suzana C. Santos ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Essential Oil ◽  
Spatial Structure ◽  
Eugenia Dysenterica ◽  
Conservation And Management

scholarly journals Population Genetic Structure and Habitat Connectivity for Jaguar (Panthera onca) Conservation in Central Belize.

2019 ◽  
Author(s):  
Angelica Menchaca ◽  
Natalia Rossi ◽  
Jeremy Froidevaux ◽  
Isabela Dias-freedman ◽  
Anthony Caragiulo ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Structure ◽  
Genetic Connectivity ◽  
Suitable Habitat ◽  
Fine Scale ◽  
Panthera Onca ◽  
Wildlife Sanctuary ◽  
Landscape Permeability ◽  
Forest Reserve

Abstract Connectivity among jaguar (Panthera onca) populations will ensure natural gene flow and the long-term survival of the species throughout its range. Jaguar conservation efforts have focused primarily on connecting suitable habitat in a broad-scale. Accelerated habitat reduction, human-wildlife conflict, limited funding, and the complexity of jaguar behaviour have proven challenging to maintain connectivity between populations effectively. Here, we used non-invasive genetic sampling and individual-based conservation genetic analyses to assess genetic diversity and levels of genetic connectivity between individuals in the Cockscomb Basin Wildlife Sanctuary and the Maya Forest Corridor. We used expert knowledge and scientific literature to develop models of landscape permeability based on circuit theory with fine-scale landscape features as ecosystem types, distance to human settlements and roads to predict the most probable jaguar movement across central Belize. Results We used 12 highly polymorphic microsatellite loci to identify 50 individual jaguars. We detected high levels of genetic diversity across loci (HE= 0.61, HO= 0.55, and NA=9.33). Using Bayesian clustering and multivariate models to assess gene flow and genetic structure, we identified one single group of jaguars (K = 1). We identified critical areas for jaguar movement that fall outside the boundaries of current protected areas in central Belize. We detected two main areas of high landscape permeability in a stretch of approximately 18 km between Sittee River Forest Reserve and Manatee Forest Reserve that may increase functional connectivity and facilitate jaguar dispersal from and to Cockscomb Basin Wildlife Sanctuary. Our analysis provides important insights on fine-scale genetic and landscape connectivity of jaguars in central Belize, an area of conservation concern. Conclusions The results of our study demonstrate high levels of relatively recent gene flow for jaguars between two study sites in central Belize. Our landscape analysis detected corridors of expected jaguar movement between the Cockscomb Basin Wildlife Sanctuary and the Maya Forest Corridor. We highlight the importance of maintaining already established corridors and consolidating new areas that further promote jaguar movement across suitable habitat beyond the boundaries of currently protected areas. Continued conservation efforts within identified corridors will further maintain and increase genetic connectivity in central Belize.

scholarly journals Effects of inbreeding on number of piglets born total, born alive and weaned in Austrian Large White and Landrace pigs

2009 ◽  
Vol 52 (1) ◽  
pp. 51-64 ◽  
Author(s):  
A. Köck ◽  
B. Fürst-Waltl ◽  
R. Baumung
Keyword(s):  
Inbreeding Depression ◽  
Reproductive Performance ◽  
Regression Models ◽  
Inbreeding Coefficient ◽  
Significant Positive Effect ◽  
Weaned Piglets ◽  
Large White ◽  
Inbreeding Coefficients ◽  
Negative Effect ◽  
Positive Effect

Abstract. In this study records of 58 925 litters of Austrian Large White and 17 846 litters of Austrian Landrace pigs were analysed. Regression models were used to determine the effects of litter, dam and sire inbreeding on total number of born, born alive and weaned piglets in Large White and Landrace. In both populations, litter and dam inbreeding showed a negative effect on all traits. Sire inbreeding had no effect in Large White, whereas a significant positive effect was observed in Landrace. On average, inbred sires with an inbreeding coefficient of 10 % had 0.45 more piglets born total and 0.43 more piglets born alive in comparison to non-inbred sires. In a further analysis the total inbreeding coefficients of the animals were divided into two parts: »new« and »old« inbreeding. »New« inbreeding was defined as the period of the first five generations. It was shown that the observed inbreeding effects were not only caused by recent inbreeding. Reproductive performance was also affected by »old« inbreeding. Finally partial inbreeding coefficients of four important ancestors in each population were calculated to investigate if inbreeding effects are similar among these ancestors. The results revealed a varation of inbreeding effects among the four ancestors. Alleles contibuting to inbreeding depression were descendent from specific ancestors.

Inbreeding and loss of genetic diversity increase extinction risk

2019 ◽  
pp. 31-48
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Inbreeding Depression ◽  
Environmental Changes ◽  
Extinction Risk ◽  
Raw Material ◽  
Heterozygote Advantage ◽  
Isolated Populations ◽  
Survival And Reproduction ◽  
Loss Of Genetic Diversity ◽  
Harmful Effects

Inbreeding reduces survival and reproduction (i.e. it causes inbreeding depression), and thereby increases extinction risk. Inbreeding depression is due to increased homozygosity for harmful alleles and at loci exhibiting heterozygote advantage. Inbreeding depression is nearly universal in sexually reproducing organisms that are diploid or have higher ploidies. Impacts of inbreeding are generally greater in species that naturally outbreed than those that inbreed, in stressful than benign environments, and for fitness than peripheral traits. Harmful effects accumulate across the life cycle, resulting in devastating effects on total fitness in outbreeding species.Species face ubiquitous environmental change and must adapt or they will go extinct. Genetic diversity is the raw material required for evolutionary adaptation. However, loss of genetic diversity is unavoidable in small isolated populations, diminishing their capacity to evolve in response to environmental changes, and thereby increasing extinction risk.

scholarly journals Reproductive Assurance Maintains Red-Flowered Plants of Lysimachia arvensis in Mediterranean Populations Despite Inbreeding Depression

2020 ◽  
Vol 11 ◽  
Author(s):  
Francisco J. Jiménez-López ◽  
Pedro L. Ortiz ◽  
María Talavera ◽  
Montserrat Arista
Keyword(s):  
Genetic Diversity ◽  
Genetic Differentiation ◽  
Inbreeding Depression ◽  
Abiotic Factors ◽  
Natural Populations ◽  
Flower Color ◽  
Selfed Progeny ◽  
Mediterranean Populations ◽  
Mediterranean Areas ◽  
Flower Color Polymorphism

Flower color polymorphism, an infrequent but phylogenetically widespread condition in plants, is captivating because it can only be maintained under a few selective regimes but also because it can drive intra-morph assortative mating and promote speciation. Lysimachia arvensis is a polymorphic species with red or blue flowered morphs. In polymorphic populations, which are mostly Mediterranean, pollinators prefer blue-flowered plants to the red ones, and abiotic factors also favors blue-flowered plants. We hypothesize that the red morph is maintained in Mediterranean areas due to its selfing capacity. We assessed inbreeding depression in both color morphs in two Mediterranean populations and genetic diversity was studied via SSR microsatellites in 20 natural populations. Results showed that only 44–47% of selfed progeny of the red plants reached reproduction while about 72–91% of blue morph progeny did it. Between-morph genetic differentiation was high and the red morph had a lower genetic diversity and a higher inbreeding coefficient, mainly in the Mediterranean. Results suggest that selfing maintaining the red morph in Mediterranean areas despite its inbreeding depression. In addition, genetic differentiation between morphs suggests a low gene flow between them, suggesting reproductive isolation.

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