02540nas a2200253   4500008004100000245016000041210006900201260001200270300001200282490000700294520168100301653001901982653002202001653001502023653001202038653001902050653002902069100001602098700001302114700001102127700001402138700001702152856011702169       2009                        eng d00aHigh allozyme diversity and unidirectional linear migration patterns within a population of tetraploid Isoetes sinensis, a rare and endangered pteridophyte0 aHigh allozyme diversity and unidirectional linear migration patt  c2009///  a52 - 580 v903 aIsoetes sinensis (Isoetaceae), an aquatic quillwort which occurs only in two fragmented sites of China as an allotetraploid, is critically endangered. Genetic variation among eight subpopulations of I. sinensis was examined in the Xin'an River (119°14′-15′E, 29°28′N) by using allozyme polymorphism. Eighteen loci of 10 enzyme systems were examined and used for the analysis of population genetic parameters. As expected for allotetraploids, fixed heterozygosity was found at four loci. A high level of genetic diversity was observed in the population, with mean number of alleles per loci of 1.8, and mean percentage of polymorphic loci of 55.6%, which were much higher than the average values in fern species. The genetic variation within each subpopulation was not positively correlated with its size, which may be explained by high gene flow (Nm = 2.57), clonal reproduction and fixed heterozygosity of allopolyploid. The I. sinensis population contained high clonal diversity (PD = 0.39, D = 0.95), indicating the successful seedling recruitment of the population. Significant positive relationship was detected between clonal diversity and the size of subpopulation. Partitioning the genetic diversity indicated that 91.1% of the genetic variation was within subpopulations and only 8.9% existed among subpopulations. The migration pattern of I. sinensis along the Xin'an River is best explained by a source-sink model, but with unidirectional gene flow among subpopulations underlined by hydrochoric force. The results were then discussed in relation to both in situ and ex situ conservation efforts of the population. © 2008 Elsevier B.V. All rights reserved.10aAllotetraploid10aGenetic diversity10aHydrochory10aIsoetes10aRiparian plant10aUnidirectional migration1 aChen, Y.-Y.1 aYang, W.1 aLi, W.1 aLi, Z.-Z.1 aHuang, H.-W.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-54249105798&partnerID=40&md5=962f14606c468408a8b8d98333cd329202091nas a2200229   4500008004100000245013800041210006900179260001200248300001400260490000800274520130400282653000901586653002201595653002201617653002301639653002801662100001601690700001301706700001101719700001401730856011701744       2010                        eng d00aGenetic diversity and population structure of the endangered alpine quillwort Isoetes hypsophila Hand.-Mazz. revealed by AFLP markers0 aGenetic diversity and population structure of the endangered alp  c2010///  a127 - 1390 v2903 aIsoetes hypsophila Hand.-Mazz. (Isoetaceae) is an endangered quillwort endemic to the Qinghai-Tibetan Plateau. Genetic variation and population structure of 12 I. hypsophila populations were examined by using amplified fragment length polymorphism (AFLP) markers. Eight primer pairs produced a total of 472 unambiguous bands, of which 229 (48.5%) were polymorphic. Intra-population genetic variation of Isoetes hypsophila was low (PP = 14.9%, HE = 0.039, hs = 0.084 and I = 0.061). The F statistics calculated by different approaches consistently revealed high genetic differentiation among populations, contributing approximately 50% of total gene diversity. Four genetic groups corresponding to four geographic regions were detected, indicating significant geographic structure. Our results suggest that both ongoing evolutionary forces (e.g., inbreeding system, bottlenecks resulting from fluctuation of water level) and historical events (e.g., orogenic movements which reduce gene flow among populations, repeated population retreat, and recolonization during ice ages) may have contributed to the genetic structure of I. hypsophila. In conservation, attention should be paid to preserving every population, and intra-region translocations can currently be recommended. © 2010 Springer-Verlag.10aAFLP10aAquatic quillwort10aGenetic structure10aIsoetes hypsophila10aQinghai-Tibetan Plateau1 aChen, Y.-Y.1 aLiao, L.1 aLi, W.1 aLi, Z.-Z.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-78149498133&partnerID=40&md5=4c18cfb671d1d50e919e742e3bf8659301941nas a2200253   4500008004100000245015600041210006900197260001200266300001200278490000700290520107700297653001901374653002201393653001201415653002201427653001901449653002501468100001601493700001601509700001701525700001401542700001401556856011701570       2012                        eng d00aMicrosatellite analysis reveals the genetic structure and gene flow of the aquatic quillwort Isoetes sinensis, a critically endangered species in China0 aMicrosatellite analysis reveals the genetic structure and gene f  c2012///  a52 - 570 v963 aIsoetes sinensis is a critically endangered aquatic quillwort, occurring in two fragmented sites of China (Xiuning county of Anhui; Jiande county of Zhejiang). During a five-year period (2004-2009), the areas and sizes of the two populations diminished dramatically due to intensive human activities. Genetic structure of the species was investigated using simple sequence repeat makers (SSRs). For seven nuclear microsatellites, high levels of genetic diversity were found within populations (H E=0.324-0.447). Strong genetic differentiation was detected between populations (G ST=0.376), while weak genetic differentiation was found within populations (G ST=0.026-0.080). Notably, in contrast to the source-sink model suggested by previous study (Chen et al., 2009), the migration pattern of I. sinensis along the Xin'an River is best explained by the linear symmetrical non-adjacent flow model (LSNF), which indicates that intensive human activities of recent years have greatly affected the gene exchange pattern among I. sinensis subpopulations. © 2011 Elsevier B.V.10aAllotetraploid10aGenetic diversity10aIsoetes10aMigration pattern10aRiparian plant10aStepping-stone model1 aChen, Y.-Y.1 aKong, D.-R.1 aHuang, C.-H.1 aXu, Y.-X.1 aLi, Z.-Z.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-84855293635&partnerID=40&md5=824e647a2989ecda4486a69d98cdaac202034nas a2200253   4500008004100000245013900041210006900180260001200249300001200261490000700273520118700280653001701467653001401484653002201498653002301520653001401543653003301557100001401590700001401604700001501618700001401633700001601647856011701663       2013                        eng d00aGenetic diversity and population structure of the endangered alpine quillwort Isoetes hypsophila (Isoetaceae) revealed by SSR analysis0 aGenetic diversity and population structure of the endangered alp  c2013///  a11 - 200 v473 aIsoetes hypsophila Hand.-Mazz. (Isoetaceae) is an endangered alpine quillwort endemic to the Qinghai-Tibetan Plateau (QTP). A total of 247 individuals of I. hypsophila from 11 populations were analyzed using ten pairs simple sequence repeats (SSR) markers. Seventy-seven alleles were recorded, with an average of 7.7 alleles per locus (ranging from 3 to 12) and the expected heterozygosity (HE) ranged from 0.392 to 0.536 (average 0.471). Clear population structure among I. hypsophila populations was found and the proportion of genetic differentiation among populations accounted for about 20% of total genetic diversity (FST = 0.178; probability of allelic co-ancestory Fcoal = 0.238). This genetic structure was probably due to limited gene flow hindered by complex terrains, bottlenecks resulting from water fluctuation in habitats, and repeated population retreat and recolonization during the ice ages. In conservation, four management units corresponding to four geographic regions were suggested, and the populations from different management units with higher genetic variation should be the priority targets of both in situ and ex situ conservation. © 2012 Elsevier Ltd.10aConservation10aGene flow10aGenetic structure10aIsoetes hypsophila10aQuillwort10aSimple sequence repeat (SSR)1 aLi, X.-L.1 aLi, S.-C.1 aChu, H.-J.1 aLi, Z.-Z.1 aChen, Y.-Y.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-84875089755&partnerID=40&md5=c1cc33debe532b0ac82fdd9916012f95