Temporal aspects of the fine-scale genetic structure in a population of Cinnamomum insularimontanum (Lauraceae)

Chung, Mi Yoon; Nason, John D.; Epperson, Bryan K.

doi:10.1038/sj.hdy.6800187

Cited by 47 publications

(46 citation statements)

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“…This regenerative local population may be attributable to extensive seedmediated gene flow. Independent and long-distance dispersal of single-seeded fruits may account for extensive gene flow and little spatial genetic structuring, in contrast to the effects of correlated seed dispersal, for example, in intact multiseeded fruits (Epperson and Alvarez-Buylla, 1997;Chung et al, 2000;Chung et al, 2003b).…”

Section: Discussionmentioning

confidence: 99%

Spatial genetic structure of two sympatric neotropical palms with contrasting life histories

2005

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The spatial genetic structure within sympatric populations of two neotropical dioecious palm species with contrasting life histories was characterized to evaluate the influence of life history traits on the extent of genetic isolation by distance. Chamaedorea tepejilote is a common wind-pollinated arboreal understory palm. Chamaedorea elatior is an uncommon climbing subcanopy palm with entomophilous pollination syndrome. A total of 59 allozyme alleles for C. tepejilote and 53 alleles for C. elatior was analyzed using both unweighted (I u ) and weighted (I w ) Moran's I spatial autocorrelation statistics. The spatial genetic structure detected within these populations is consistent with those reported for highly dispersed plants. A significance test for differences between mean Moran's I-coefficients revealed less spatial genetic structure within the C. tepejilote population than that in the C. elatior population. Adjacent individuals of C. elatior exhibited significant spatial genetic autocorrelation (I u ¼ 0.039, I w ¼ 0.034), indicating a Wright's neighborhood size of about 100 individuals. For C. tepejilote, nonrandom genetic distribution among nearest neighbors was detected, even from small spatial autocorrelation values (I u ¼ 0.008, I w ¼ 0.009), consistent with a neighborhood size of about 300 individuals. For both species, seed dispersal, mortality among life cycle stages, overlapping generations, and contrasting traits of mating and reproduction influence the standing spatial genetic structure within populations. Heredity (2005) 95, 298-305.

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Section: Discussionmentioning

confidence: 99%

Spatial genetic structure of two sympatric neotropical palms with contrasting life histories

2005

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“…The spatial distributions of allozyme polymorphisms were analyzed separately for age classes I through VII using both Moran's Istatistics (Sokal and Oden 1978) and a pairwise estimate of genetic correlation, f ij (''coancestry'' coefficient; sensu Kalisz et al 2001), which measures the correlation between the frequency of a random allele from one individual with that of a random allele from another (Cockerham 1969). f ij has been used in a number of recent studies (e.g., Loiselle et al 1995 Kalisz et al 2001;Parker et al 2001;Chung et al 2002;Chung et al 2003). Values of I-statistics averaged over alleles allowed indirect estimation of Wright's (1943) neighborhood size (Epperson and Li 1996;Epperson et al 1999;Chung and Epperson 1999;Epperson and Chung 2001).…”

Section: Discussionmentioning

confidence: 99%

“…This study demonstrates, however, that the intensity of the internal spatial genetic structure can vary among age classes (i.e., seedlings, juveniles, and adults). This suggests that studies of spatial genetic structure in species with overlapping generations must focus on a range of age classes to reveal the total picture of genetic structure in local populations (Tonsor et al 1993;Alvarez-Buylla et al 1996;Kitamura et al 1997a,b;Kalisz et al 2001;Chung et al 2003).…”

Section: Genetic Diversity and Structure Within And Between Age Classesmentioning

confidence: 99%

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Genetic Structure of Age Classes in Camellia Japonica (Theaceae)

2003

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Abstract. Camellia japonica L. (Theaceae), an insect-and bird-pollinated, broad-leaved evergreen tree, is widely distributed in Japan and the southern Korean peninsula. The species has a relatively even age distribution within populations, which may influence the spatial genetic structure of different age classes relative to species with typical L-shaped age distributions. To determine whether the internal spatial genetic structure found in seedlings and young individuals carries over into adults, we used allozyme loci, F-statistics, spatial autocorrelation statistics (Moran's I), and coancestry measures to examine changes in genetic structure among seven age classes in a population (60-m ϫ 100-m area) in southern Korea. In seedlings, weak but significant positive values of Moran's I-statistics and coancestry measures were found for distances less than 14 m, which is consistent with a mechanism of limited seed dispersal combined with overlapping seed shadows. This spatial structure, however, dissipates in older age classes, and in adults genetic variation has an essentially random spatial distribution. Morisita's index of dispersion of individuals in each age class showed that seedlings and juveniles are more highly clustered than are older individuals. These results suggest that self-thinning changes the spatial relationships of individuals, and thus genotypes. A multilocus estimate of F ST (0.008) shows a small but statistically significant difference in allele frequencies among age classes. In summary, intrapopulation genetic structure within and among age classes of C. japonica was significant but weak. Despite presumably limited seed dispersal, weak spatial genetic structure in juveniles suggests overlapping seed shadows followed by self-thinning during recruitment. The present study also demonstrates that studies of spatial genetic structure focusing on limited numbers of generations may not be sufficient to reveal the entire picture of genetic structure in populations with overlapping generations. Theoretical models have shown that the genetic structure of local populations is affected by various nonequilibrium processes (Slatkin 1977;Wade and McCauley 1988). Genetic and demographic factors, such as pollen and seed dispersal from neighboring parents, past major reproductive events, selection, and other processes determining the life history of a species, influence population genetic processes (Jain and Bradshaw

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“…In many temperate tree species, particularly the more common wind-pollinated species, seed dispersal may have a much greater impact than pollen flow on spatial genetic structure at the fine-and local-scales (Chung et al 2003); this is because seeds are not expected to move as far as pollen (Heuertz et al 2003;Sato et al 2006). In the case of a riparian habitat, plant species usually exhibit seed dispersal involving more than one phase: the primary phase is via gravity-, wind-or animal-dispersal, and is followed by a secondary phase of water-dispersal (hydrochory).…”

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confidence: 99%

Multiple-scaled spatial genetic structures of Fraxinus mandshurica over a riparian–mountain landscape in Northeast China

Uchiyama

Shen

et al. 2009

Conserv Genet

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Landscape genetics increasingly focuses on the way in which landscape features cause the fragmentation of lineages of terrestrial organisms. However, landscape features can also provide functional connectivity or corridors, enhancing the dispersal of plant populations, particularly the case in riparian habitat. Unfortunately, recent research in tree genetics has paid little attention to this role. To examine the possible effects of landscape connectivity on the current population genetic distribution of Fraxinus mandshurica and to provide insights into conserving the local genetic diversity for this endangered tree species, we used nine nuclear microsatellite loci to examine the spatial genetic structure of F. mandshurica at multiple-scales over a riparian-mountain landscape in Northeast China. F-statistics indicated that the magnitude of among-population genetic differentiation was significantly higher between the riparian and mountain habitats than within the riparian habitat. Spatial analysis of molecular variance and principal coordinate analysis consistently revealed that this species exhibited a clear landscape genetic structure between the riparian and mountain habitats, despite no significant isolation by distance pattern being identified by the Mantel test. Spatial autocorrelation analysis further demonstrated significant, positive fine-scale spatial genetic structure among individuals over short distances (\80 m) in each mountain population. Conversely, no spatial genetic structures were identified within and among the riparian populations. Overall, the results suggest that seed dispersal is very low among mountain populations; however seed transport is probably enhanced by a secondary phase of hydrochory (water-dispersal) among riparian populations during flooding. Despite this, there was no significant accumulation of genetic diversity in downstream populations along the main channel. This result suggests that hydrochory is not sufficient to produce a clear unidirectional gene flow along the water course, although it may impede the development of spatial genetic structuring within and among riparian populations.

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Temporal aspects of the fine-scale genetic structure in a population of Cinnamomum insularimontanum (Lauraceae)

Cited by 47 publications

References 45 publications

Spatial genetic structure of two sympatric neotropical palms with contrasting life histories

Spatial genetic structure of two sympatric neotropical palms with contrasting life histories

Genetic Structure of Age Classes in Camellia Japonica (Theaceae)

Multiple-scaled spatial genetic structures of Fraxinus mandshurica over a riparian–mountain landscape in Northeast China

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