The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Shinichi Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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inbreeding depression at the sapling stage and its genetic consequences in a population of the outcrossing dominant tree species castanopsis sieboldii
Tree Genetics & Genomes, 2015Co-Authors: Atsushi Nakanishi, Hiroshi Yoshimaru, Nobuhiro Tomaru, Masahiro Miura, Tohru Manabe, Shinichi YamamotoAbstract:Highly frequent Pollination at short distances combined with spatial genetic structure (SGS) among reproductive individuals, as observed in populations of many forest tree species, may lead to highly frequent Pollinations between genetically related individuals located close to each other. This could increase frequencies of biparental inbreeding and strengthen the degree of SGS across generations. However, the degree of SGS observed in forest tree populations is not usually strong, suggesting that such processes are restricted by other factors, which may include inbreeding depression. To test this hypothesis, we examined inbreeding depression in Castanopsis sieboldii saplings in a population known to have significant SGS and high frequencies of short-distance Pollination. We determined genotypes at eight microsatellite loci of 125 adult trees and 899 saplings in a 4-ha plot. The neighborhood model approach, assuming an exponential power function, showed highly frequent Pollination at short distance among parents of saplings. SGS was significantly stronger among saplings than among adults. The average value of F is (individual inbreeding coefficient based on kinship coefficients between genes within individuals) was also significantly higher among saplings than among adults. Furthermore, average values for saplings were relatively high (0.036–0.052) in 30–50 to 90–110 cm height classes and rapidly decreased to 0.006 for the ≥110-cm class. Analysis of covariance, taking into account the canopy state, showed that inbreeding depression had a significant negative effect on the saplings’ height. Thus, the level of inbreeding in saplings decreased with size classes increasing, probably due to pronounced inbreeding depression resulting in mortality or reduced growth of inbred saplings, and hence, the inbreeding depression may prevent increasing of the level of inbreeding and the degree of SGS in subsequent generations.
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patterns of pollen flow in a dense population of the insect pollinated canopy tree species castanopsis sieboldii
Journal of Heredity, 2012Co-Authors: Atsushi Nakanishi, Hiroshi Yoshimaru, Nobuhiro Tomaru, Masahiro Miura, Tohru Manabe, Shinichi YamamotoAbstract:Insect Pollinations of tree species with high-density populations have rarely been studied. Since the density of adults can affect effective pollen dispersal, short-distance Pollination, even by insects, may frequently occur in high-density populations. To test this prediction, we investigated Pollination patterns in a high-density population of the insect-pollinated canopy tree species Castanopsis sieboldii by paternity analysis using genotypes at 8 microsatellite loci of 145 adult trees and 439 seeds from 11 seed parents in a 4-ha plot. We then explored their genetic effects on the population by calculating other population genetics parameters. Although C. sieboldii has high potential for long-distance dispersal of pollen (as indicated by a fat-tailed dispersal kernel), the cumulative Pollination at the local scale was spatially limited and strongly dependent on the distance between parents due to the high density of adults. Genetic diversity estimates for pollen pools accepted by each seed parent converged on a maximum as the effective number of pollen parents increased. The genetic diversity of pollen pool bulked over all the seed parents from inside the plot did not differ from that of the total pollen pools. Therefore, although pollen flow from distant pollen parents may help to maintain the genetic diversity of offspring, pollen parents neighboring seed parents may be the main contributors to the genetic diversity of the offspring at the seed stage.
Atsushi Nakanishi - One of the best experts on this subject based on the ideXlab platform.
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inbreeding depression at the sapling stage and its genetic consequences in a population of the outcrossing dominant tree species castanopsis sieboldii
Tree Genetics & Genomes, 2015Co-Authors: Atsushi Nakanishi, Hiroshi Yoshimaru, Nobuhiro Tomaru, Masahiro Miura, Tohru Manabe, Shinichi YamamotoAbstract:Highly frequent Pollination at short distances combined with spatial genetic structure (SGS) among reproductive individuals, as observed in populations of many forest tree species, may lead to highly frequent Pollinations between genetically related individuals located close to each other. This could increase frequencies of biparental inbreeding and strengthen the degree of SGS across generations. However, the degree of SGS observed in forest tree populations is not usually strong, suggesting that such processes are restricted by other factors, which may include inbreeding depression. To test this hypothesis, we examined inbreeding depression in Castanopsis sieboldii saplings in a population known to have significant SGS and high frequencies of short-distance Pollination. We determined genotypes at eight microsatellite loci of 125 adult trees and 899 saplings in a 4-ha plot. The neighborhood model approach, assuming an exponential power function, showed highly frequent Pollination at short distance among parents of saplings. SGS was significantly stronger among saplings than among adults. The average value of F is (individual inbreeding coefficient based on kinship coefficients between genes within individuals) was also significantly higher among saplings than among adults. Furthermore, average values for saplings were relatively high (0.036–0.052) in 30–50 to 90–110 cm height classes and rapidly decreased to 0.006 for the ≥110-cm class. Analysis of covariance, taking into account the canopy state, showed that inbreeding depression had a significant negative effect on the saplings’ height. Thus, the level of inbreeding in saplings decreased with size classes increasing, probably due to pronounced inbreeding depression resulting in mortality or reduced growth of inbred saplings, and hence, the inbreeding depression may prevent increasing of the level of inbreeding and the degree of SGS in subsequent generations.
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patterns of pollen flow in a dense population of the insect pollinated canopy tree species castanopsis sieboldii
Journal of Heredity, 2012Co-Authors: Atsushi Nakanishi, Hiroshi Yoshimaru, Nobuhiro Tomaru, Masahiro Miura, Tohru Manabe, Shinichi YamamotoAbstract:Insect Pollinations of tree species with high-density populations have rarely been studied. Since the density of adults can affect effective pollen dispersal, short-distance Pollination, even by insects, may frequently occur in high-density populations. To test this prediction, we investigated Pollination patterns in a high-density population of the insect-pollinated canopy tree species Castanopsis sieboldii by paternity analysis using genotypes at 8 microsatellite loci of 145 adult trees and 439 seeds from 11 seed parents in a 4-ha plot. We then explored their genetic effects on the population by calculating other population genetics parameters. Although C. sieboldii has high potential for long-distance dispersal of pollen (as indicated by a fat-tailed dispersal kernel), the cumulative Pollination at the local scale was spatially limited and strongly dependent on the distance between parents due to the high density of adults. Genetic diversity estimates for pollen pools accepted by each seed parent converged on a maximum as the effective number of pollen parents increased. The genetic diversity of pollen pool bulked over all the seed parents from inside the plot did not differ from that of the total pollen pools. Therefore, although pollen flow from distant pollen parents may help to maintain the genetic diversity of offspring, pollen parents neighboring seed parents may be the main contributors to the genetic diversity of the offspring at the seed stage.
Christopher T Frye - One of the best experts on this subject based on the ideXlab platform.
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benefits of gene flow are mediated by individual variability in self compatibility in small isolated populations of an endemic plant species
Evolutionary Applications, 2017Co-Authors: Christopher T Frye, Maile C NeelAbstract:Many rare and endemic species experience increased rates of self-fertilization and mating among close relatives as a consequence of existing in small populations within isolated habitat patches. Variability in self-compatibility among individuals within populations may reflect adaptation to local demography and genetic architecture, inbreeding, or drift. We use experimental hand-Pollinations under natural field conditions to assess the effects of gene flow in 21 populations of the central Appalachian endemic Trifolium virginicum that varied in population size and degree of isolation. We quantified the effects of distance from pollen source on Pollination success and fruit set. Rates of self-compatibility varied dramatically among maternal plants, ranging from 0-100%. This variation was unrelated to population size or degree of isolation. Nearly continuous variation in the success of selfing and near-cross matings via hand-Pollination suggest that T. virginicum expresses pseudo-self-fertility, whereby plants carrying the same S allele mate successfully by altering the self-incompatibility reaction. However, outcrossing among populations produced significantly higher fruit set than within populations, an indication of drift load. These results are consistent with strong selection acting to break down self-incompatibility in these small populations and/or early acting inbreeding depression expressed upon selfing. This article is protected by copyright. All rights reserved.
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Benefits of gene flow are mediated by individual variability in self‐compatibility in small isolated populations of an endemic plant species
Evolutionary Applications, 2016Co-Authors: Christopher T Frye, Maile C NeelAbstract:Many rare and endemic species experience increased rates of self-fertilization and mating among close relatives as a consequence of existing in small populations within isolated habitat patches. Variability in self-compatibility among individuals within populations may reflect adaptation to local demography and genetic architecture, inbreeding, or drift. We use experimental hand-Pollinations under natural field conditions to assess the effects of gene flow in 21 populations of the central Appalachian endemic Trifolium virginicum that varied in population size and degree of isolation. We quantified the effects of distance from pollen source on Pollination success and fruit set. Rates of self-compatibility varied dramatically among maternal plants, ranging from 0-100%. This variation was unrelated to population size or degree of isolation. Nearly continuous variation in the success of selfing and near-cross matings via hand-Pollination suggest that T. virginicum expresses pseudo-self-fertility, whereby plants carrying the same S allele mate successfully by altering the self-incompatibility reaction. However, outcrossing among populations produced significantly higher fruit set than within populations, an indication of drift load. These results are consistent with strong selection acting to break down self-incompatibility in these small populations and/or early acting inbreeding depression expressed upon selfing. This article is protected by copyright. All rights reserved.
Maile C Neel - One of the best experts on this subject based on the ideXlab platform.
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benefits of gene flow are mediated by individual variability in self compatibility in small isolated populations of an endemic plant species
Evolutionary Applications, 2017Co-Authors: Christopher T Frye, Maile C NeelAbstract:Many rare and endemic species experience increased rates of self-fertilization and mating among close relatives as a consequence of existing in small populations within isolated habitat patches. Variability in self-compatibility among individuals within populations may reflect adaptation to local demography and genetic architecture, inbreeding, or drift. We use experimental hand-Pollinations under natural field conditions to assess the effects of gene flow in 21 populations of the central Appalachian endemic Trifolium virginicum that varied in population size and degree of isolation. We quantified the effects of distance from pollen source on Pollination success and fruit set. Rates of self-compatibility varied dramatically among maternal plants, ranging from 0-100%. This variation was unrelated to population size or degree of isolation. Nearly continuous variation in the success of selfing and near-cross matings via hand-Pollination suggest that T. virginicum expresses pseudo-self-fertility, whereby plants carrying the same S allele mate successfully by altering the self-incompatibility reaction. However, outcrossing among populations produced significantly higher fruit set than within populations, an indication of drift load. These results are consistent with strong selection acting to break down self-incompatibility in these small populations and/or early acting inbreeding depression expressed upon selfing. This article is protected by copyright. All rights reserved.
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Benefits of gene flow are mediated by individual variability in self‐compatibility in small isolated populations of an endemic plant species
Evolutionary Applications, 2016Co-Authors: Christopher T Frye, Maile C NeelAbstract:Many rare and endemic species experience increased rates of self-fertilization and mating among close relatives as a consequence of existing in small populations within isolated habitat patches. Variability in self-compatibility among individuals within populations may reflect adaptation to local demography and genetic architecture, inbreeding, or drift. We use experimental hand-Pollinations under natural field conditions to assess the effects of gene flow in 21 populations of the central Appalachian endemic Trifolium virginicum that varied in population size and degree of isolation. We quantified the effects of distance from pollen source on Pollination success and fruit set. Rates of self-compatibility varied dramatically among maternal plants, ranging from 0-100%. This variation was unrelated to population size or degree of isolation. Nearly continuous variation in the success of selfing and near-cross matings via hand-Pollination suggest that T. virginicum expresses pseudo-self-fertility, whereby plants carrying the same S allele mate successfully by altering the self-incompatibility reaction. However, outcrossing among populations produced significantly higher fruit set than within populations, an indication of drift load. These results are consistent with strong selection acting to break down self-incompatibility in these small populations and/or early acting inbreeding depression expressed upon selfing. This article is protected by copyright. All rights reserved.
Nobuhiro Tomaru - One of the best experts on this subject based on the ideXlab platform.
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inbreeding depression at the sapling stage and its genetic consequences in a population of the outcrossing dominant tree species castanopsis sieboldii
Tree Genetics & Genomes, 2015Co-Authors: Atsushi Nakanishi, Hiroshi Yoshimaru, Nobuhiro Tomaru, Masahiro Miura, Tohru Manabe, Shinichi YamamotoAbstract:Highly frequent Pollination at short distances combined with spatial genetic structure (SGS) among reproductive individuals, as observed in populations of many forest tree species, may lead to highly frequent Pollinations between genetically related individuals located close to each other. This could increase frequencies of biparental inbreeding and strengthen the degree of SGS across generations. However, the degree of SGS observed in forest tree populations is not usually strong, suggesting that such processes are restricted by other factors, which may include inbreeding depression. To test this hypothesis, we examined inbreeding depression in Castanopsis sieboldii saplings in a population known to have significant SGS and high frequencies of short-distance Pollination. We determined genotypes at eight microsatellite loci of 125 adult trees and 899 saplings in a 4-ha plot. The neighborhood model approach, assuming an exponential power function, showed highly frequent Pollination at short distance among parents of saplings. SGS was significantly stronger among saplings than among adults. The average value of F is (individual inbreeding coefficient based on kinship coefficients between genes within individuals) was also significantly higher among saplings than among adults. Furthermore, average values for saplings were relatively high (0.036–0.052) in 30–50 to 90–110 cm height classes and rapidly decreased to 0.006 for the ≥110-cm class. Analysis of covariance, taking into account the canopy state, showed that inbreeding depression had a significant negative effect on the saplings’ height. Thus, the level of inbreeding in saplings decreased with size classes increasing, probably due to pronounced inbreeding depression resulting in mortality or reduced growth of inbred saplings, and hence, the inbreeding depression may prevent increasing of the level of inbreeding and the degree of SGS in subsequent generations.
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patterns of pollen flow in a dense population of the insect pollinated canopy tree species castanopsis sieboldii
Journal of Heredity, 2012Co-Authors: Atsushi Nakanishi, Hiroshi Yoshimaru, Nobuhiro Tomaru, Masahiro Miura, Tohru Manabe, Shinichi YamamotoAbstract:Insect Pollinations of tree species with high-density populations have rarely been studied. Since the density of adults can affect effective pollen dispersal, short-distance Pollination, even by insects, may frequently occur in high-density populations. To test this prediction, we investigated Pollination patterns in a high-density population of the insect-pollinated canopy tree species Castanopsis sieboldii by paternity analysis using genotypes at 8 microsatellite loci of 145 adult trees and 439 seeds from 11 seed parents in a 4-ha plot. We then explored their genetic effects on the population by calculating other population genetics parameters. Although C. sieboldii has high potential for long-distance dispersal of pollen (as indicated by a fat-tailed dispersal kernel), the cumulative Pollination at the local scale was spatially limited and strongly dependent on the distance between parents due to the high density of adults. Genetic diversity estimates for pollen pools accepted by each seed parent converged on a maximum as the effective number of pollen parents increased. The genetic diversity of pollen pool bulked over all the seed parents from inside the plot did not differ from that of the total pollen pools. Therefore, although pollen flow from distant pollen parents may help to maintain the genetic diversity of offspring, pollen parents neighboring seed parents may be the main contributors to the genetic diversity of the offspring at the seed stage.
