AOBPreview originally published online on May 4, 2006
Annals of Botany 2006 98(1):165-173; doi:10.1093/aob/mcl083
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Fine-scale Genetic Structure among Genetic Individuals of the Clone-Forming Monotypic Genus Echinosophora koreensis (Fabaceae)
1 Division of Specimen and Genetic Resources, National Arboretum, Korea Forest Service, Gyeonggi Province, 487-821, Republic of Korea, 2 School of Biological Sciences, Seoul National University, Seoul 151-742, Republic of Korea and 3 Department of Biology and Institute of Basic Science, Gyeongsang National University, Jinju 660-701, Republic of Korea
* For correspondence. E-mail s_myc{at}gaechuk.gsnu.ac.kr or mgchung{at}nongae.gsnu.ac.kr
Received: 5 October 2005 Returned for revision: 22 December 2005 Accepted: 13 February 2006 Published electronically: 4 May 2006
Background and Aims For rare endemics or endangered plant species that reproduce both sexually and vegetatively it is critical to understand the extent of clonality because assessment of clonal extent and distribution has important ecological and evolutionary consequences with conservation implications. A survey was undertaken to understand clonal effects on fine-scale genetic structure (FSGS) in two populations (one from a disturbed and the other from an undisturbed locality) of Echinosophora koreensis, an endangered small shrub belonging to a monotypic genus in central Korea that reproduces both sexually and vegetatively via rhizomes.
Methods Using inter-simple sequence repeats (ISSRs) as genetic markers, the spatial distribution of individuals was evaluated using Ripley's L(d)-statistics and quantified the spatial scale of clonal spread and spatial distribution of ISSR genotypes using spatial autocorrelation analysis techniques (join-count statistics and kinship coefficient, Fij) for total samples and samples excluding clones.
Key Results A high degree of differentiation between populations was observed (
ST(g) = 0·184, P < 0·001). Ripley's L(d)-statistics revealed a near random distribution of individuals in a disturbed population, whereas significant aggregation of individuals was found in an undisturbed site. The join-count statistics revealed that most clones significantly aggregate at
6-m interplant distance. The Sp statistic reflecting patterns of correlograms revealed a strong pattern of FSGS for all four data sets (Sp = 0·0720·154), but these patterns were not significantly different from each other. At small interplant distances (
2 m), however, jackknifed 95 % CIs revealed that the total samples exhibited significantly higher Fij values than the same samples excluding clones.
Conclusion The strong FSGS from genets is consistent with two biological and ecological traits of E. koreensis: bee-pollination and limited seed dispersal. Furthermore, potential clone mates over repeated generations would contribute to the observed high Fij values among genets at short distance. To ensure long-term ex situ genetic variability of the endangered E. koreensis, individuals located at distances of 1012 m should be collected across entire populations of E. koreensis.
Key words: Clonal structure, conservation, Echinosophora koreensis, monotypic genus, Fabaceae, fine-scale genetic structure, genets, ISSRs, sampling strategies