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I Sehmi - One of the best experts on this subject based on the ideXlab platform.
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familial down syndrome evidence supporting Cytoplasmic Inheritance
Clinical Genetics, 2002Co-Authors: S Arbuzova, Howard Cuckle, R Mueller, I SehmiAbstract:The frequently observed familial aggregation of Down syndrome (DS) 47,+21 and other aneuploidies and the phenomenon of double aneuploidy involving DS cannot be accounted for by chance alone. To clarify possible aetiological factors, pedigrees from all 7 affected families with repeated marriages referred to two regional genetics centres were examined. In each case the recurrence of aneuploidy was on the mother's side (p<0.01). Such a pattern suggests Cytoplasmic Inheritance of a risk factor. The hypothesis that mitochondrial DNA mutations have a role in the aetiology of DS is supported by other observations as well as by theoretical considerations.
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Familial Down syndrome: evidence supporting Cytoplasmic Inheritance
Clinical genetics, 2002Co-Authors: S Arbuzova, Howard Cuckle, R Mueller, I SehmiAbstract:The frequently observed familial aggregation of Down syndrome (DS) 47,+21 and other aneuploidies and the phenomenon of double aneuploidy involving DS cannot be accounted for by chance alone. To clarify possible aetiological factors, pedigrees from all 7 affected families with repeated marriages referred to two regional genetics centres were examined. In each case the recurrence of aneuploidy was on the mother's side (p
Sodmergen - One of the best experts on this subject based on the ideXlab platform.
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Potential Cytoplasmic Inheritance in Wisteria sinensis and Robinia pseudoacacia (Leguminosae)
Plant & cell physiology, 2005Co-Authors: Quan Zhang, SodmergenAbstract:We examined pollen cells of Wisteria sinensis and Robinia pseudoacacia (Leguminosae) to determine a possible mode for Cytoplasmic Inheritance in these species. Epifluorescence microscopy revealed distinct mature generative cells. Mature generative cells of W. sinensis were associated with large numbers of punctuated fluorescent signals corresponding to Cytoplasmic DNA aggregates, but no fluorescent signals were observed in the generative cells of R. pseudoacacia. Closer examination showed that the punctate fluorescent signals corresponded to plastid but not mitochondrial DNA. These results suggest a strong potential for paternal transmission of the plastid genome in W. sinensis. Electron microscopy confirmed the presence of plastids in the generative cells of W. sinensis and the absence of plastids in R. pseudoacacia cells due to an unequal distribution of plastids during the first pollen mitosis. Mitochondria were present and intact in the mature generative cells of both species. The lack of fluoresced mitochondrial DNA suggests a very low level of mitochondrial DNA in the cells. Immunoelectron microscopy demonstrated that the labeling of mitochondrial DNA in these cells was reduced by nearly 90% during pollen development. Such a dramatic reduction suggests an active degradation of paternal mitochondrial DNA, which may contribute greatly to the maternal Inheritance of mitochondria. In short, we found that W. sinensis exhibits a strong potential for paternal transmission of plastids and that both W. sinensis and R. pseudoacacia appear to share the same mechanism for maternal mitochondrial Inheritance.
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Divergent Potentials for Cytoplasmic Inheritance within the Genus Syringa. A New Trait Associated with Speciogenesis
Plant physiology, 2004Co-Authors: Yang Liu, Quan Zhang, Hongxia Cui, SodmergenAbstract:Epifluorescence microscopic detection of organelle DNA in the mature generative cell is a rapid method for determining the potential for the mode of Cytoplasmic Inheritance. We used this method to examine 19 of the known 22 to 27 species in the genus Syringa. Organelle DNA was undetectable in seven species, all in the subgenus Syringa, but was detected in the 12 species examined of the subgenera Syringa and Ligustrina. Therefore, species within the genus Syringa display differences in the potential Cytoplasmic Inheritance. Closer examination revealed that the mature generative cells of the species in which organelle DNA was detected contained both mitochondria and plastids, but cells of the species lacking detectable organelle DNA contained only mitochondria, and the epifluorescent organelle DNA signals from the mature generative cells corresponded to plastid DNA. In addition, semiquantitative analysis was used to demonstrate that, during pollen development, the amount of mitochondrial DNA decreased greatly in the generative cells of the species examined, but the amount of plastid DNA increased remarkably in the species containing plastids in the generative cell. The results suggest that all Syringa species exhibit potential maternal mitochondrial Inheritance, and a number of the species exhibit potential biparental plastid Inheritance. The difference between the modes of potential plastid Inheritance among the species suggests different phylogenies for the species; it also supports recent conclusions of molecular, systematic studies of the Syringa. In addition, the results provide new evidence for the mechanisms of maternal mitochondrial Inheritance in angiosperms.
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Examination of the Cytoplasmic DNA in male reproductive cells to determine the potential for Cytoplasmic Inheritance in 295 angiosperm species.
Plant & cell physiology, 2003Co-Authors: Qouan Zhang, Yang Liu, SodmergenAbstract:Mature pollen grains of 295 angiosperm species were screened by epifluorescence microscopy for a marker that denotes the mode of Cytoplasmic Inheritance. We used the DNA fluorochrome DAPI (4',6-diamidino-2-phenylindole) for pollen cell staining. The presence or absence of fluorescence of Cytoplasmic DNA in the generative cell or sperm cells was examined in each species. The species examined represented 254 genera and 98 families, and 40 of these families had not been previously studied in this regard. The Cytoplasmic DNA of the generative cell or sperm cells did not fluoresce in 81% of the species examined, from 83% of the genera and 87% of the families examined, indicating the potential for maternal Cytoplasmic Inheritance in these species. In contrast, the male reproductive cells of 19% of the species, from 17% of the genera and 26% of the families examined, displayed fluorescence of the Cytoplasmic DNA, indicating the potential for biparental Cytoplasmic Inheritance in these species. The results revealed the potential for biparental Cytoplasmic Inheritance in several species in which the Inheritance mode was previously unknown, including plants in the Bignoniaceae, Cornaceae, Cruciferae (Brassicaceae), Cyperaceae, Dipsacaceae, Hydrocharitaceae, Papaveraceae, Portulacaceae, Tiliaceae, Valerianaceae, and Zingiberaceae. Electron microscopy revealed that the sperm cells of Portulaca grandiflora contain both plastid and mitochondrial DNA. However, in the generative cells of Musella lasiocarpa, the mitochondria contain DNA, but the plastids do not. These data provide a foundation for further studies of Cytoplasmic Inheritance in angiosperms.
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Potential for biparental Cytoplasmic Inheritance in Jasminum officinale and Jasminum nudiflorum
Sexual Plant Reproduction, 1998Co-Authors: Sodmergen, H. H. Bai, Haruko Kuroiwa, Shigeyuki Kawano, T. KuroiwaAbstract:Mature Jasminum officinale and J. nudiflorum pollen grains were stained with 4′,6-diamidino-2-phenylindole (DAPI) and examined by epifluorescence microscopy. The pollen grains were found to be trinucleate, and the sperm cells in both species contained a large number of epifluorescent spots that corresponded to Cytoplasmic DNA aggregates (nucleoids). The nucleoids of J. nudiflorum were observed to be dimorphic under the epifluorescence microscope, indicating that the sperm cells might contain both plastid and mitochondrial DNA. The nucleoids of J. officinale presented a similar appearance when stained with DAPI, but electron microscopic examination of the sperm cells revealed that they contained both plastids and mitochondria. When analyzed by DNA immunogold electron microscopy, gold particles were detected on both plastids and mitochondria. These findings demonstrated the preservation of plastid and mitochondrial DNA in mature sperm cells and thus the potential for biparental Cytoplasmic Inheritance in J. officinale and J. nudiflorum.
M A Asmussen - One of the best experts on this subject based on the ideXlab platform.
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Comparative effects of pollen and seed migration on the cytonuclear structure of plant populations. II. Paternal Cytoplasmic Inheritance.
Genetics, 1992Co-Authors: A Schnabel, M A AsmussenAbstract:We continue our study of the effects of pollen and seed migration on the cytonuclear structure of mixed-mating plant populations by analyzing two deterministic continent-island models under the critical assumption of paternal Cytoplasmic Inheritance. The major results of this study that contrast with our previous conclusions based on maternal Cytoplasmic Inheritance are (i) pollen gene flow can significantly affect the cytonuclear structure of the island population, and in particular can help to generate cytonuclear disequilibria that greatly exceed the magnitude of those that would be produced by seed migration or mixed mating alone; (ii) with simultaneous pollen and seed migration, nonzero cytonuclear disequilibria will be maintained not only when there is disequilibrium in the immigrant pollen or seeds, but also through a variety of intermigrant admixture effects when the two pools of immigrants differ appropriately in their cytonuclear compositions; (iii) either immigrant pollen or immigrant seeds can generate disequilibria de novo in populations with initially random cytonuclear associations, but pollen migration alone generally produces lower levels of disequilibrium than does comparable seed migration, especially at high levels of self-fertilization when the overall fraction of immigrant pollen is low; (iv) the equilibrium state of the island population will be influenced by the rate of pollen gene flow whenever there is either allelic disequilibrium in the immigrant pollen or simultaneous seed migration coupled with different Cytoplasmic or nuclear allele frequencies in immigrant pollen and seeds or nonzero allelic disequilibrium in either immigrant pool. The estimation of pollen migration should therefore be facilitated with paternal Cytoplasmic Inheritance relative to the case of maternal Cytoplasmic Inheritance. These basic conclusions hold whether the population is censused as seeds or as adults, but with simultaneous pollen and seed migration, the relationship between census time and the ability to detect nonrandom cytonuclear associations is complex. When migration is through pollen alone, however, the cytonuclear structure of the island population is independent of the life stage censused.
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Comparative effects of pollen and seed migration on the cytonuclear structure of plant populations. I. Maternal Cytoplasmic Inheritance.
Genetics, 1991Co-Authors: M A Asmussen, A SchnabelAbstract:Abstract We explicitly solve and analyze a series of deterministic continent-island models to delimit the effects of pollen and seed migration on cytonuclear frequencies and disequilibria in random-mating, mixed-mating and self-fertilized populations. Given the critical assumption of maternal Cytoplasmic Inheritance, five major findings are (i) nonzero cytonuclear disequilibria will be maintained in the island population if and only if at least some migration occurs each generation through seeds with nonrandom cytonuclear associations; (ii) immigrant seeds with no cytonuclear disequilibria can strongly affect the genetic structure of the island population by generating significant and long-lasting transient associations; (iii) with all else being equal, substantially greater admixture disequilibria are generally found with higher rates of seed migration into, or higher levels of self-fertilization within, the island population (with the possible exception of the heterozygote disequilibrium); (iv) pollen migration can either enhance or reduce the cytonuclear disequilibria caused by seed migration, or that due to mixed-mating in the absence of seed migration, but the effect is usually small and appears primarily to make a noticeable difference in predominantly outcrossing populations; and (v) pollen migration alone cannot generate even transient disequilibria de novo in populations with completely random associations. This same basic behavior is exhibited as long as there is some random outcrossing in the island population. Self-fertilized populations represent a special case, however, in that they are necessarily closed to pollen migration, and nonzero disequilibria can be maintained even in the absence of seed migration. All of these general results hold whether the population is censused as adults or as seeds, but the ability to detect nonrandom cytonuclear associations can depend strongly on the life stage censused in populations with a significant level of random outcrossing. We suggest how these models might be used for the estimation of seed and pollen migration.
A Schnabel - One of the best experts on this subject based on the ideXlab platform.
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Comparative effects of pollen and seed migration on the cytonuclear structure of plant populations. II. Paternal Cytoplasmic Inheritance.
Genetics, 1992Co-Authors: A Schnabel, M A AsmussenAbstract:We continue our study of the effects of pollen and seed migration on the cytonuclear structure of mixed-mating plant populations by analyzing two deterministic continent-island models under the critical assumption of paternal Cytoplasmic Inheritance. The major results of this study that contrast with our previous conclusions based on maternal Cytoplasmic Inheritance are (i) pollen gene flow can significantly affect the cytonuclear structure of the island population, and in particular can help to generate cytonuclear disequilibria that greatly exceed the magnitude of those that would be produced by seed migration or mixed mating alone; (ii) with simultaneous pollen and seed migration, nonzero cytonuclear disequilibria will be maintained not only when there is disequilibrium in the immigrant pollen or seeds, but also through a variety of intermigrant admixture effects when the two pools of immigrants differ appropriately in their cytonuclear compositions; (iii) either immigrant pollen or immigrant seeds can generate disequilibria de novo in populations with initially random cytonuclear associations, but pollen migration alone generally produces lower levels of disequilibrium than does comparable seed migration, especially at high levels of self-fertilization when the overall fraction of immigrant pollen is low; (iv) the equilibrium state of the island population will be influenced by the rate of pollen gene flow whenever there is either allelic disequilibrium in the immigrant pollen or simultaneous seed migration coupled with different Cytoplasmic or nuclear allele frequencies in immigrant pollen and seeds or nonzero allelic disequilibrium in either immigrant pool. The estimation of pollen migration should therefore be facilitated with paternal Cytoplasmic Inheritance relative to the case of maternal Cytoplasmic Inheritance. These basic conclusions hold whether the population is censused as seeds or as adults, but with simultaneous pollen and seed migration, the relationship between census time and the ability to detect nonrandom cytonuclear associations is complex. When migration is through pollen alone, however, the cytonuclear structure of the island population is independent of the life stage censused.
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Comparative effects of pollen and seed migration on the cytonuclear structure of plant populations. I. Maternal Cytoplasmic Inheritance.
Genetics, 1991Co-Authors: M A Asmussen, A SchnabelAbstract:Abstract We explicitly solve and analyze a series of deterministic continent-island models to delimit the effects of pollen and seed migration on cytonuclear frequencies and disequilibria in random-mating, mixed-mating and self-fertilized populations. Given the critical assumption of maternal Cytoplasmic Inheritance, five major findings are (i) nonzero cytonuclear disequilibria will be maintained in the island population if and only if at least some migration occurs each generation through seeds with nonrandom cytonuclear associations; (ii) immigrant seeds with no cytonuclear disequilibria can strongly affect the genetic structure of the island population by generating significant and long-lasting transient associations; (iii) with all else being equal, substantially greater admixture disequilibria are generally found with higher rates of seed migration into, or higher levels of self-fertilization within, the island population (with the possible exception of the heterozygote disequilibrium); (iv) pollen migration can either enhance or reduce the cytonuclear disequilibria caused by seed migration, or that due to mixed-mating in the absence of seed migration, but the effect is usually small and appears primarily to make a noticeable difference in predominantly outcrossing populations; and (v) pollen migration alone cannot generate even transient disequilibria de novo in populations with completely random associations. This same basic behavior is exhibited as long as there is some random outcrossing in the island population. Self-fertilized populations represent a special case, however, in that they are necessarily closed to pollen migration, and nonzero disequilibria can be maintained even in the absence of seed migration. All of these general results hold whether the population is censused as adults or as seeds, but the ability to detect nonrandom cytonuclear associations can depend strongly on the life stage censused in populations with a significant level of random outcrossing. We suggest how these models might be used for the estimation of seed and pollen migration.
S Arbuzova - One of the best experts on this subject based on the ideXlab platform.
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familial down syndrome evidence supporting Cytoplasmic Inheritance
Clinical Genetics, 2002Co-Authors: S Arbuzova, Howard Cuckle, R Mueller, I SehmiAbstract:The frequently observed familial aggregation of Down syndrome (DS) 47,+21 and other aneuploidies and the phenomenon of double aneuploidy involving DS cannot be accounted for by chance alone. To clarify possible aetiological factors, pedigrees from all 7 affected families with repeated marriages referred to two regional genetics centres were examined. In each case the recurrence of aneuploidy was on the mother's side (p<0.01). Such a pattern suggests Cytoplasmic Inheritance of a risk factor. The hypothesis that mitochondrial DNA mutations have a role in the aetiology of DS is supported by other observations as well as by theoretical considerations.
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Familial Down syndrome: evidence supporting Cytoplasmic Inheritance
Clinical genetics, 2002Co-Authors: S Arbuzova, Howard Cuckle, R Mueller, I SehmiAbstract:The frequently observed familial aggregation of Down syndrome (DS) 47,+21 and other aneuploidies and the phenomenon of double aneuploidy involving DS cannot be accounted for by chance alone. To clarify possible aetiological factors, pedigrees from all 7 affected families with repeated marriages referred to two regional genetics centres were examined. In each case the recurrence of aneuploidy was on the mother's side (p
