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Asymmetric Introgression in the Horticultural Living Fossil Cycas Sect. Asiorientales Using a Genome-Wide Scanning Approach
Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
Department of Biological Science and Technology, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
Department of Life Science, National Taiwan Normal University, Taipei 116, Taiwan
Taiwan Forestry Research Institute, Technical Service Division, Taipei 10066, Taiwan
These authors contributed equally to this work.
* Author to whom correspondence should be addressed.
Received: 23 December 2012; in revised form: 25 March 2013 / Accepted: 26 March 2013 / Published: 15 April 2013
Abstract: The Asian cycads are mostly allopatric, distributed in small population sizes. Hybridization between allopatric species provides clues in determining the mechanism of species divergence. Horticultural introduction provides the chance of interspecific gene flow between allopatric species. Two allopatrically eastern Asian Cycas sect. Asiorientales species, C. revoluta and C. taitungensis, which are widely distributed in Ryukyus and Fujian Province and endemic to Taiwan, respectively, were planted in eastern Taiwan for horticultural reason. Higher degrees of genetic admixture in cultivated samples than wild populations in both cycad species were detected based on multilocus scans by neutral AFLP markers. Furthermore, bidirectional but asymmetric introgression by horticultural introduction of C. revoluta is evidenced by the reanalyses of species associated loci, which are assumed to be diverged after species divergence. Partial loci introgressed from native cycad to the invaders were also detected at the loci of strong species association. Consistent results tested by all neutral loci, and the species-associated loci, specify the recent introgression from the paradox of sharing of ancestral polymorphisms. Phenomenon of introgression of cultivated cycads implies niche conservation among two geographic-isolated cycads, even though the habitats of the extant wild populations of two species are distinct.
Keywords: introgression; AFLP; Cycas revoluta; Cycas taitungensis; horticulture
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MDPI and ACS Style
Chiang, Y.-C.; Huang, B.-H.; Chang, C.-W.; Wan, Y.-T.; Lai, S.-J.; Huang, S.; Liao, P.-C. Asymmetric Introgression in the Horticultural Living Fossil Cycas Sect. Asiorientales Using a Genome-Wide Scanning Approach. Int. J. Mol. Sci. 2013, 14, 8228-8251.
Chiang Y-C, Huang B-H, Chang C-W, Wan Y-T, Lai S-J, Huang S, Liao P-C. Asymmetric Introgression in the Horticultural Living Fossil Cycas Sect. Asiorientales Using a Genome-Wide Scanning Approach. International Journal of Molecular Sciences. 2013; 14(4):8228-8251.
Chiang, Yu-Chung; Huang, Bing-Hong; Chang, Chun-Wen; Wan, Yu-Ting; Lai, Shih-Jie; Huang, Shong; Liao, Pei-Chun. 2013. "Asymmetric Introgression in the Horticultural Living Fossil Cycas Sect. Asiorientales Using a Genome-Wide Scanning Approach." Int. J. Mol. Sci. 14, no. 4: 8228-8251.