An investigation into effects of long-distance seed dispersal on organelle population genetic structure and colonization rate: a model analysis

Puccinia striiformis f. sp. tritici is the causal pathogen of interregional epidemics of wheat stripe rust in China via long-distance migration. Gansu Province serves as putative inoculum center providing oversummering inoculum, while Sichuan Basin area serves as a region providing huge amounts of overwintering inoculum. Thus, the relationship between these two regions in population exchange and migration become important in prediction of interregional epidemics. In this study, we compared the population genetic structure and race composition between Gansu and Sichuan Basin populations to infer their migration relationships. A total of 526 isolates, spanning 3 years, were genotyped using eight pairs of amplified fragment length polymorphism markers, and a subset of 98 isolates were inoculated onto 19 Chinese differentials to perform the race analysis. Twenty-three common races and 26 shared genotypes supplied molecular evidence for migration between Gansu and Sichuan Basin populations. Bayesian assignment and principal component analysis revealed that the genetic group assignment of the Sichuan Basin populations (10SB and 11SB) changed in the spring to align with the fall Gansu populations in the prior seasons (09GS and 10GS), which indicated an asymmetric migration from Gansu Province to the Sichuan Basin area. The linkage disequilibrium and the parsimony tree length permutation test revealed a strong annual recombination signal in the Gansu populations and an inconsistent signal in the Sichuan Basin populations.

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Population genetic structure of two Medicago species shaped by distinct life form, mating system and seed dispersal

Annals of Botany ◽

10.1093/aob/mcp006 ◽

2009 ◽

Vol 103 (6) ◽

pp. 825-834 ◽

Cited By ~ 27

Author(s):

Juan Yan ◽

Hai-Jia Chu ◽

Heng-Chang Wang ◽

Jian-Qiang Li ◽

Tao Sang

Keyword(s):

Genetic Structure ◽

Seed Dispersal ◽

Mating System ◽

Population Genetic Structure ◽

Population Genetic ◽

Life Form ◽

Medicago Species

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Genetic diversity and population genetic structure in fragmented Allocasuarina verticillata (Allocasuarinaceae) – implications for restoration

Australian Journal of Botany ◽

10.1071/bt11253 ◽

2011 ◽

Vol 59 (8) ◽

pp. 770 ◽

Cited By ~ 17

Author(s):

Linda M. Broadhurst

Keyword(s):

Genetic Diversity ◽

Genetic Structure ◽

Population Genetic Structure ◽

Population Genetic ◽

Gene Diversity ◽

Natural Populations ◽

Long Distance ◽

Study Region ◽

Allocasuarina Verticillata ◽

Seed Crops

Vegetation restoration in fragmented regions is constrained by limited supplies of high quality seed and an understanding of the scale over which seed can be moved without causing negative outcomes. ‘Local’ seed is often prescribed for restoration but in fragmented landscapes this restricts collecting to small, inbred populations. Six polymorphic microsatellites were used to examine genetic diversity and population genetic structure in seed collected from 18 fragmented natural populations and three restored populations of the wind-pollinated and dispersed tree Allocasuarina verticillata, a key restoration species. Smaller populations produced seed crops with significantly fewer alleles, lower allelic richness and less gene diversity. Most of the populations assessed, including the restored sites, produce genetically diverse seed crops suitable for restoration but smaller populations (<30 plants) should be augmented with seed from larger populations. Principal coordinate analysis, graph-theory and Bayesian analyses found little evidence of spatially predictable genetic structure across the study region, which probably reflects long distance gene dispersal preventing the development of strong spatial structure. The absence of strong spatial patterns suggests that seed can be moved beyond current 5–50-km limits while being mindful of strong selection gradients or conditions that might indicate locally adapted populations.

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Impacts of Seed and Pollen Flow on Population Genetic Structure for Plant Genomes With Three Contrasting Modes of Inheritance

Genetics ◽

10.1093/genetics/152.1.441 ◽

1999 ◽

Vol 152 (1) ◽

pp. 441-450 ◽

Cited By ~ 2

Author(s):

Xin-Sheng Hu ◽

Richard A Ennos

Keyword(s):

Genetic Structure ◽

Population Genetic Structure ◽

Population Genetic ◽

Nuclear Genes ◽

Effective Population ◽

Long Distance ◽

Stepping Stone ◽

Animal Populations ◽

And Migration ◽

Stepping Stone Model

Abstract The classical island and one-dimensional stepping-stone models of population genetic structure developed for animal populations are extended to hermaphrodite plant populations to study the behavior of biparentally inherited nuclear genes and organelle genes with paternal and maternal inheritance. By substituting appropriate values for effective population sizes and migration rates of the genes concerned into the classical models, expressions for genetic differentiation and correlation in gene frequency between populations can be derived. For both models, differentiation for maternally inherited genes at migration-drift equilibrium is greater than that for paternally inherited genes, which in turn is greater than that for biparentally inherited nuclear genes. In the stepping-stone model, the change of genetic correlation with distance is influenced by the mode of inheritance of the gene and the relative values of long- and short-distance migration by seed and pollen. In situations where it is possible to measure simultaneously Fst for genes with all three types of inheritance, estimates of the relative rates of pollen to seed flow can be made for both the short- and long-distance components of migration in the stepping-stone model.

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