Variation in the nrDNA ITS of Pinus Subsection Cembroides: Implications for Molecular Systematic Studies of Pine Species Complexes

Gernandt, David S.; Liston, Aaron; Piñero, Daniel

doi:10.1006/mpev.2001.1026

Cited by 77 publications

(65 citation statements)

References 51 publications

(84 reference statements)

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“…punctulatus group. Similar long stem-loop secondary structures have also been observed in the tandemly arrayed subrepeats present in the ITS1 of pinyon pines (Gernandt et al 2001). …”

Section: Its1 Internal Repeatssupporting

confidence: 62%

“…melas (Paskewitz et al 1993). ITS1 lengths of up to 2.5 kb also occur in ladybird beetles (von der Schulenburg et al 2001) and can exceed 3 kb in pinyon pines (Gernandt et al 2001). The wide range of observed lengths attests to the repeated recombination of internal repeats, which has led to some interpopulation differences, as seen in An.…”

Section: Intraindividual Variationmentioning

confidence: 99%

“…Long ITS1 repeats in ladybird beetles and pinyon pines have also formed into paralogous repeat types within a tandem array (a.k.a. positional homologues), which may also promote recombination (von der Schulenburg et al 2001;Gernandt et al 2001). It is significant that a high level of homogenization was observed within species for each repeat type and within the An.…”

Section: Its1 Internal Repeatsmentioning

confidence: 99%

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Internal Repetition and Intraindividual Variation in the rDNA ITS1 of the Anopheles punctulatus Group (Diptera: Culicidae): Multiple Units and Rates of Turnover

Bower

Cooper²,

Beebe

2009

J Mol Evol

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The rapid divergence of repetitive sequences makes them desirable markers for phylogenetic studies of closely related groups, provided that a high level of sequence homogeneity has been maintained within species. Intraspecific polymorphisms are found in an increasing number of studies now, and this highlights the need to determine why these occur. In this study we examined intraindividual variation present in the first ribosomal internal transcribed spacer (ITS1) from a group of cryptic mosquito species. Individuals of the Anopheles punctulatus group contained multiple ITS1 length variants that ranged from 1.2 to 8.0 kb. Nucleotide and copy number variation for several homologous internal repeats is common, yet the intraspecific sequence divergence of cloned PCR isolates is comparable to that of other mosquito species (*0.2-1.5%). Most of the length variation is comprised of a 5 0 -ITS1 repeat that was identified as a duplication of a conserved ITS2 region. Secondary structure conservation for this repeat is pronounced and several repeat types that are highly homogenized have formed. Significant interspecific divergence indicates a high rate of evolutionary change for this spacer. A maximum likelihood tree constructed here was congruent with previous phylogenetic hypotheses and suggests that concerted evolution is also accompanied by interpopulation divergence. The lack of interindividual differences and the presence of homogenized internal repeats suggest that a high rate of turnover has reduced the overall level of variation. However, the intraindividual variation also appears to be maintained by the absence of a single turnover rate and the complex dynamics of ongoing recombination within the spacer.

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“…punctulatus group. Similar long stem-loop secondary structures have also been observed in the tandemly arrayed subrepeats present in the ITS1 of pinyon pines (Gernandt et al 2001). …”

Section: Its1 Internal Repeatssupporting

confidence: 62%

Section: Intraindividual Variationmentioning

confidence: 99%

Section: Its1 Internal Repeatsmentioning

confidence: 99%

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Internal Repetition and Intraindividual Variation in the rDNA ITS1 of the Anopheles punctulatus Group (Diptera: Culicidae): Multiple Units and Rates of Turnover

Bower

Cooper²,

Beebe

2009

J Mol Evol

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“…Moreover, genetic distance between some populations within P. engelmannii was as great as the mean genetic distance between P. engelmannii and P. mexicana. For comparison, we (Ledig et al 2001) found that D averaged 0.218 between Pinus pinceana Gordon (weeping piñon) and Pinus maximartinezii Rzedowski (maxipiñon), two morphologically distinct pine species that belong to the same subsection of Pinus (section Strobus, subsection Cembroides; Gernandt et al 2001). Picea mexicana populations approach this level of differentiation from P. engelmannii only when compared to P. engelmannii from Panther Creek, Salmon National Forest, Idaho, the most geographically distant population from P. mexicana in our sample; the mean genetic distance (nine loci) between the Panther Creek population of P. engelmannii and P. mexicana was 0.232, which is signi cantly different [Volume 29 SYSTEMATIC BOTANY from the mean genetic distance of P. mexicana from all other populations of P. engelmannii, 0.137 (t 5 7.48, df 5 28).…”

Section: Identity Of Species and Variation Among Populationsmentioning

confidence: 99%

Relationships among the Spruces (Picea, Pinaceae) of Southwestern North America

et al. 2004

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“…For some authors, this species is considered of relictual origin and phylogenetic studies show a basal position on the topologies of the Cembroides group [63][64][65]. Therefore, the isolation and fragmentation of their populations are important factors that could be affect pollen flow among them.…”

Section: Contrasting Reproductive Indicatorsmentioning

confidence: 99%

Reproductive Success and Inbreeding Differ in Fragmented Populations of Pinus rzedowskii and Pinus ayacahuite var. veitchii, Two Endemic Mexican Pines under Threat

Sánchez

Delgado-Valerio

Sáenz‐Romero

et al. 2016

Forests

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Abstract:Seed production, quality, germination and seedling establishment are indicators of reproductive success in conifers. Monitoring of these parameters is essential to determine the viability of populations for the purposes of conservation. We analyze cone and seed traits as indicators of reproductive success in the endangered Rzedowski´s pine (Pinus rzedowskii (Madrigal et Caballero) and near-threatened veitchii pine (Pinus ayacahuite var. veitchii (Shaw)) in west-central Michoacán, Mexico. These traits were systematically quantified and their variation assessed using Generalized Linear Mixed Models (GLMMs). We found that the reproductive success of Rzedowski's pine seems to be critical, presenting low seed efficiency (17.10%), germination (5.0%) and seedling establishment (27.7%), with high levels of inbreeding (0.79). In contrast, veitchii pine presents moderate seed efficiency (54.9%), high germination (71.5%) and seedling establishment (84%-97%) and low inbreeding (0.33). Reproductive indicators differed significantly among zones and populations for each species, where fragment sizes mainly affected seed production and efficiency. This result indicates that fragmentation has played a more important role in the reproductive success of Rzedowski's pine than in veitchii pine, perhaps by limiting pollen flow among zones and populations and producing higher levels of inbreeding and lower seed efficiency in the former species. We propose a conservation strategy for these important pine species in order to increase their long-term genetic viability.

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Variation in the nrDNA ITS of Pinus Subsection Cembroides: Implications for Molecular Systematic Studies of Pine Species Complexes

Cited by 77 publications

References 51 publications

Internal Repetition and Intraindividual Variation in the rDNA ITS1 of the Anopheles punctulatus Group (Diptera: Culicidae): Multiple Units and Rates of Turnover

Internal Repetition and Intraindividual Variation in the rDNA ITS1 of the Anopheles punctulatus Group (Diptera: Culicidae): Multiple Units and Rates of Turnover

Relationships among the Spruces (Picea, Pinaceae) of Southwestern North America

Reproductive Success and Inbreeding Differ in Fragmented Populations of Pinus rzedowskii and Pinus ayacahuite var. veitchii, Two Endemic Mexican Pines under Threat

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