Chloroplast DNA evidence for the origin of the genus
            <i>Heterogaura</i>
            from a species of
            <i>Clarkia</i>
            (Onagraceae)

Sytsma, Kenneth J.; Gottlieb, L. D.

doi:10.1073/pnas.83.15.5554

Cited by 97 publications

(53 citation statements)

References 22 publications

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“…Carpenteria (Hydrangeaceae), an evergreen shrub from the Sierra Nevada, is an example of a monotypic, putatively paleoendemic genus evidently nested phylogenetically within another genus, a pattern usually associated with young taxa (e.g., Sytsma & Gottlieb 1986) and warranting taxonomic attention. Carpenteria was resolved as having diverged from within the mock oranges (Philadelphus) in the late Oligocene, after the divergence of southwestern North American taxa of Philadelphus subg.…”

Section: Wwwannualreviewsorg • Origins Of Californian Plant Diversimentioning

confidence: 99%

Origins of Plant Diversity in the California Floristic Province

Baldwin

2014

Annu. Rev. Ecol. Evol. Syst.

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Recent biogeographic and evolutionary studies have led to improved understanding of the origins of exceptionally high plant diversity in the California Floristic Province (CA-FP). Spatial analyses of Californian plant diversity and endemism reinforce the importance of geographically isolated areas of high topographic and edaphic complexity as floristic hot spots, in which the relative influence of factors promoting evolutionary divergence and buffering of lineages against extinction has gained increased attention. Molecular phylogenetic studies spanning the flora indicate that immediate sources of CA-FP lineages bearing endemic species diversity have been mostly within North America-especially within the west and southwest-even for groups of north temperate affinity, and that most diversification of extant lineages in the CA-FP has occurred since the mid-Miocene, with the transition toward summer-drying. Process-focused studies continue to implicate environmental heterogeneity at local or broad geographic scales in evolutionary divergence within the CA-FP, often associated with reproductive or life-history shifts or sometimes hybridization.

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Section: Wwwannualreviewsorg • Origins Of Californian Plant Diversimentioning

confidence: 99%

Origins of Plant Diversity in the California Floristic Province

Baldwin

2014

Annu. Rev. Ecol. Evol. Syst.

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“…-Mean sequence divergence ranged from 0.3 to 0.4% among the three Helianthus taxa analyzed. These estimates are similar to values obtained for closely related species ofLycopersicon (0-0.7%; Palmer and Zamir, 1982), Pennisetum (0.4%; Clegg et aI., 1984), Pisum (0.1-0.8%; Palmer et aI., 1985), and Lisianthius (0-0.3%; Sytsma and Schaal, 1985b), but generally lower than es-timates obtained in Brassica (0.3-2.6%;Palmer et al, 1983), Clarkia (0.2-1.6%;Sytsma and Gottlieb, 1986), and Linum (0-6%; Coates and Cullis, 1987). However, mean sequence divergence between the two races ofH.…”

Section: Discussionmentioning

confidence: 99%

A MOLECULAR REEXAMINATION OF INTROGRESSION BETWEEN HELIANTHUS ANNUUS AND H. BOLANDERI (COMPOSITAE)

1988

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Abstract. -Heiser (1949) hypothesized that a weedy race of Helianthus bolanderi had originated by the introgression of genes from H. annuus into a serpentine race of H. bolanderi. Although Heiser's investigation of these species is frequently cited as one ofthe best examples ofintrogression in plants, definitive evidence of gene exchange is lacking (Heiser, 1973). To determine whether the weedy race of H. bolanderi actually originated via introgression, we analyzed allozyme, chloroplast-DNA (cpDNA), and nuclear-ribosomal-DNA (rDNA) variation.Evidence from enzyme electrophoresis did not support the proposed introgressive origin ofweedy H. bolanderi. We detected a total of 37 low-frequency alleles distinguishing the serpentine race of H. bolanderi from H. annuus. Weedy H. bolanderi possessed only four of the 37 marker alleles. Further analysis demonstrated that serpentine H. bolanderi combined seven of the 35 alleles distinguishing H. annuus from weedy H. bolanderi, indicating that serpentine H. bolanderi shares three more marker alleles with H. annuus than does weedy H. bolanderi. These results are similar to expectations for race divergence from a single common ancestor and suggest that, ifintrogression occurred, the majority of marker alleles were rapidly lost following the initial hybridization event.Even more compelling evidence opposing Heiser's (1949) hypothesis, however, was from restriction-fragment analysis of cpDNA and nuclear rDNA. We detected a total of 17 cpDNA and five rDNA restriction-site mutations among the 19 populations examined. No parallel or back mutations were observed in phylogenetic trees constructed using eithercpDNA or rDNA mutations, and both phylogenies were completely congruent regarding the alignment of all three taxa. In addition, the weedy race of H. bolanderi possessed a unique cpDNA, which was outside the range of variation observed among populations of either ofthe presumed parental species. Mean sequence divergences between the cpDNAs of weedy H. bolanderi and those of serpentine H. bolanderi and H. annuus were 0.30% and 0.35%, respectively. These estimates are comparable to sequencedivergence values observed between closely related species in other plant groups. Given the lack of parallel or convergent mutations in the cpDNA and rDNA phylogenetic trees, the complete congruence of these trees with flavonoid-and allozyme-variation patterns, and the presence of a unique and divergent chloroplast genome in the weedy race of H. bolanderi, we suggest that the weedy race of H. bolanderi was not derived recently through introgression, as hypothesized, but is relatively ancient in origin.

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“…Because we could not detect such small changes (see also Banks and Birky [1985] and Sytsma and Gottlieb [I 986a]), we may therefore have detected only a portion of the length mutations actually present. Several investigators (Palmer, 1985a(Palmer, , 1985bPalmer et aI., 1985;Sytsma and Gottlieb, 1986a) have emphasized the difficulty in assessing whether length mutations are homologous. We therefore performed separate phylogenetic analyses that either employed or omitted these Table I]; these are difficult to interpret with purified cpDNAs, due to fragment overlap; see also Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The great evolutionary and phylogenetic value of cpDNA analysis has now been excellently documented at several taxonomic levels. Analysis of cp-DNA variation has clarified relationships among congeneric species, including Brassica (Erickson et al, 1983;Palmer et al, 1983), Lycopersicon (Palmer and Zamir, 1982), Lisianthius (Sytsma and Schaal, 1985), Clarkia (Sytsma and Gottlieb, 1986a), Pisum (Palmer et al, 1985), Linum (Coates and Cullis, 1987), and Cucumis (Perl-Treves and Galun, 1985). At the generic level, cpDNA data demonstrated that the monotypic Heterogaura originated from within Clarkia (Sytsma and Gottlieb, 1986b).…”

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confidence: 99%