Apomixis, hybridization, and taxonomic complexity in eastern north AmericanAmelanchier (Rosaceae)

Campbell, Christopher S.; Wright, Wesley A.

doi:10.1007/bf02815379

Cited by 31 publications

(24 citation statements)

References 21 publications

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“…Campbell et al (1997) suggested that agamospermy could be responsible for the high level of intraindividual ITS polymorphism found in the Amelanchier agamic complex (Rosaceae). Meiosis is absent in agamospermous plants; wherein megasporocytes degenerate and nearby somatic cells develop mitotically into chromosomally unreduced megagametophytes (Campbell and Wright, 1996). As a result, the heteroduplex molecules required for efficient molecular turnover and concerted evolution are missing.…”

Section: Correlates Of High Levels Of Polymorphismmentioning

confidence: 99%

Recent Origin and Phylogenetic Utility of Divergent ITS Putative Pseudogenes: A Case Study from Naucleeae (Rubiaceae)

2004

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The internal transcribed spacer (ITS) of nuclear ribosomal DNA has been widely used by systematists for reconstructing phylogenies of closely related taxa. Although the occurrence of ITS putative pseudogenes is well documented for many groups of animals and plants, the potential utility of these pseudogenes in phylogenetic analyses has often been underestimated or even ignored in part because of deletions that make unambiguous alignment difficult. In addition, long branches often can lead to spurious relationships, particularly in parsimony analyses. We have discovered unusually high levels of ITS polymorphism (up to 30%, 40%, and 14%, respectively) in three tropical tree species of the coffee family (Rubiaceae), Adinauclea fagifolia, Haldina cordifolia, and Mitragyna rubrostipulata. Both secondary structure stability and patterns of nucleotide substitutions in a highly conserved region (5.8S gene) were used for distinguishing presumed functional sequences from putative pseudogenes. The combination of both criteria was the most powerful approach. The sequences from A. fagifolia appear to be a mix of functional genes and highly distinct putative pseudogenes, whereas those from H. cordifolia and M. rubrostipulata were identified as putative pseudogenes. We explored the potential utility of the identified putative pseudogenes in the phylogenetic analyses of Naucleeae sensu lato. Both Bayesian and parsimony trees identified the same monophyletic groups and indicated that the polymorphisms do not transcend species boundaries, implying that they do not predate the divergence of these three species. The resulting trees are similar to those produced by previous analyses of chloroplast genes. In contrast to results of previous studies therefore, divergent putative pseudogenes can be useful for phylogenetic analyses, especially when no sequences of their functional counterparts are available. Our studies clearly show that ITS polymorphism may not necessarily mislead phylogenetic inference. Despite using many different PCR conditions (different primers, higher denaturing temperatures, and absence or presence of DMSO and BSA-TMACl), we recovered only a few functional ITS copies from A. fagifolia and none from H. cordifolia and M. rubrostipulata, which suggests that PCR selection is occurring and/or the presumed functional alleles are located at minor loci (with few ribosomal DNA copies).

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Section: Correlates Of High Levels Of Polymorphismmentioning

confidence: 99%

Recent Origin and Phylogenetic Utility of Divergent ITS Putative Pseudogenes: A Case Study from Naucleeae (Rubiaceae)

2004

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“…In many cases the difficulty in identifying Amelanchier material has been attributed to hybridization, introgression and agamospermy (e.g., Robinson 1982;Campbell and Wright 1996) but this aspect has yet to be investigated in the prairie region. There is much more variation in plants referred to A. alnifolia than was previously suspected.…”

Section: Resultsmentioning

confidence: 99%

Regional Variation in <em>Amelanchier</em> in the Whitewood area of Southeastern Saskatchewan and the First Saskatchewan Records of <em>Amelanchier sanguinea</em>

Catling

Mitrow

2006

Can Field Nat

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Based on measurements and evaluation of 111 specimens from 51 localities in the Whitewood area of southeastern Saskatchewan, most Amelanchier alnifolia from the prairie parkland is represented by short, stoloniferous shrubs, less than 2 m tall with 5 – 100+ stems. In the Moose Mountain area, A. alnifolia is represented by shrubs that are taller, sometimes to 7 m, not stoloniferous and usually having fewer than five stems. Although many of these plants have the inflorescence characteristics of A. alnifolia, some are referable to the eastern A. sanguinea, not previously reported from southeastern Saskatchewan. Such plants appear to be confined to the wooded environment of Moose Mountain. Amelanchier alnifolia is not as clearly differentiated by habit or leaf tip characteristics as the literature suggests. Inflorescence characteristics, habit and actual genetic variation may be associated with biogeographic patterns, especially historically wooded islands within the prairie ecozone. These patterns are an important consideration in classification studies and in protecting and utilizing Amelanchier germplasm.

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“…Despite rare exceptions (Böcher, 1951;Dobeš, Koch, & Sharbel, 2006;Siena, Sartor, Espinoza, Quarín, & Ortiz, 2008), apomicts are polyploid (Asker & Jerling, 1992;Carman, 1997;Comai, 2005;Dickinson, Lo, & Talent, 2007) and often form so-called amphi-apomictic systems with sexual diploids (e.g., Asker, 1970;Bayer, 1997;Böcher, 1951;Campbell & Wright, 1996;Hörandl & Gutermann, 1999). As a consequence, geographical and ecological parthenogenesis may depend on intrinsic effects of polyploidy (i.e., nucleotypic effects, Levin, 1983), rather than those of asexuality itself (Bierzychudek, 1985;Vandel, 1940).…”

Section: ;mentioning

confidence: 99%

Difference in reproductive mode rather than ploidy explains niche differentiation in sympatric sexual and apomictic populations ofPotentilla puberula

Alonso‐Marcos

Nardi

Scheffknecht

et al. 2019

Ecology and Evolution

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Apomicts tend to have larger geographical distributional ranges and to occur in ecologically more extreme environments than their sexual progenitors. However, the expression of apomixis is typically linked to polyploidy. Thus, it is a priori not clear whether intrinsic effects related to the change in the reproductive mode or rather in the ploidy drive ecological differentiation. We used sympatric sexual and apomictic populations of Potentilla puberula to test for ecological differentiation. To distinguish the effects of reproductive mode and ploidy on the ecology of cytotypes, we compared the niches (a) of sexuals (tetraploids) and autopolyploid apomicts (penta‐, hepta‐, and octoploids) and (b) of the three apomictic cytotypes. We based comparisons on a ploidy screen of 238 populations along a latitudinal transect through the Eastern European Alps and associated bioclimatic, and soil and topographic data. Sexual tetraploids preferred primary habitats at drier, steeper, more south‐oriented slopes, while apomicts mostly occurred in human‐made habitats with higher water availability. Contrariwise, we found no or only marginal ecological differentiation among the apomictic higher ploids. Based on the pronounced ecological differences found between sexuals and apomicts, in addition to the lack of niche differentiation among cytotypes of the same reproductive mode, we conclude that reproductive mode rather than ploidy is the main driver of the observed differences. Moreover, we compared our system with others from the literature, to stress the importance of identifying alternative confounding effects (such as hybrid origin). Finally, we underline the relevance of studying ecological parthenogenesis in sympatry, to minimize the effects of differential migration abilities.

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Apomixis, hybridization, and taxonomic complexity in eastern north AmericanAmelanchier (Rosaceae)

Cited by 31 publications

References 21 publications

Recent Origin and Phylogenetic Utility of Divergent ITS Putative Pseudogenes: A Case Study from Naucleeae (Rubiaceae)

Recent Origin and Phylogenetic Utility of Divergent ITS Putative Pseudogenes: A Case Study from Naucleeae (Rubiaceae)

Regional Variation in <em>Amelanchier</em> in the Whitewood area of Southeastern Saskatchewan and the First Saskatchewan Records of <em>Amelanchier sanguinea</em>

Difference in reproductive mode rather than ploidy explains niche differentiation in sympatric sexual and apomictic populations ofPotentilla puberula

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