Abstract
BackgroundThere has always been controversy over whether clonal plants have lower genetic diversity than plants that reproduce sexually. These conflicts could be attributed to the fact that few studies have taken into account the mating system of sexually reproducing plants and their phylogenetic distance. Moreover, most clonal plants in these previous studies regularly produce sexual progeny. Here, we describe a study examining the levels of genetic diversity and differentiation within and between local populations of fully clonal Zingiber zerumbet at a microgeographical scale and compare the results with data for the closely related selfing Z. corallinum and outcrossing Z. nudicarpum. Such studies could disentangle the phylogenetic and sexually reproducing effect on genetic variation of clonal plants, and thus contribute to an improved understanding in the clonally reproducing effects on genetic diversity and population structure.ResultsThe results revealed that the level of local population genetic diversity of clonal Z. zerumbet was comparable to that of outcrossing Z. nudicarpum and significantly higher than that of selfing Z. corallinum. However, the level of microgeographic genetic diversity of clonal Z. zerumbet is comparable to that of selfing Z. corallinum and even slightly higher than that of outcrossing Z. nudicarpum. The genetic differentiation among local populations of clonal Z. zerumbet was significantly lower than that of selfing Z. corallinum, but higher than that of outcrossing Z. nudicarpum. A stronger spatial genetic structure appeared within local populations of Z. zerumbet compared with selfing Z. corallinum and outcrossing Z. nudicarpum.ConclusionsOur study shows that fully clonal plants are able not only to maintain a high level of within-population genetic diversity like outcrossing plants, but can also maintain a high level of microgeographic genetic diversity like selfing plant species, probably due to the accumulation of somatic mutations and absence of a capacity for sexual reproduction. We suggest that conservation strategies for the genetic diversity of clonal and selfing plant species should be focused on the protection of all habitat types, especially fragments within ecosystems, while maintenance of large populations is a key to enhance the genetic diversity of outcrossing species.
Highlights
There has always been controversy over whether clonal plants have lower genetic diversity than plants that reproduce sexually
The level of microgeographic genetic diversity of clonal Z. zerumbet is comparable to that of selfing Z. corallinum (h: 0.2409 vs 0.2490, p = 0.587; I: 0.3713 vs 0.3753, p = 0.838), and even slightly higher than that of outcrossing Z. nudicarpum (h: 0.2409 vs 0.2246, p = 0.389; I: 0.3713 vs 0.3480, p = 0.493). These results suggest that, compared with outcrossing Z. nudicarpum, the genetic diversity of local populations of clonal Z. zerumbet at the microgeographic scale will be less affected by reduced gene flow because each individual contains most of the genetic variation within the population, similar to selfing Z. corallinum [44]
The observed values of clonal diversity of Z. zerumbet (G/N = 0.90; D = 0.97) were higher than the average values of clonal plant species in several literature surveys (e.g. G/N = 0.17, D = 0.67 for 21 clonal species summarized by Ellstrand and Roose [16]; G/N = 0.27; D = 0.75 for 45 clonal species reported by Widén et al [17]; G/N = 0.44; D = 0.85 for 77 clonal species reported by Honnay and Jacquemyn [19])
Summary
There has always been controversy over whether clonal plants have lower genetic diversity than plants that reproduce sexually. Asexually reproducing populations of the shrub Acacia carneorum contained multiple genets, which can be attributed to occasional sexual recruitment [13], and perennial clonal herbaceous Maianthemum bifolium showed high genotypic diversity resulting from very limited sexual recruitment [18] These previous studies did not take into account the mating system of the non-clonal plants concerned, which is the most important factor affecting genetic diversity and spatial genetic structure of populations within species [31,32,33]; that is, a comparison was not made with selfing and outcrossing plants. Comparative studies on population genetic structure between closely related obligatory clonal plant species and sexual plant species can disentangle the phylogenetic effect on genetic variation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
