Yuan-Yuan Li

East China Normal University, Shanghai, Shanghai Shi, China

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Publications (10)25.2 Total impact

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    ABSTRACT: Metasequoia glyptostroboides is a famous living fossil. It is one of the most successfully recovered endangered species based on the number of extant individuals and the distribution range. However, previous studies have revealed low genetic variation in restored populations. This paper evaluates the natural regeneration ability of the natural and restored populations. The seed masses and germination rates of restored populations were found to be significantly lower than those in natural populations, indicating decreased regeneration ability in the restored populations. The decreased germination rate in the restored populations may be due to inbreeding depression. Very low seed germination rates show that it is very difficult for the restored populations to regenerate naturally, consistent with field surveys. This is the first report on a species that has successfully produced hundreds of millions of individuals but has difficulty in regenerating naturally. Our study highlights the role of population viability analysis in delisting or downlisting species under protection.
    Biological Conservation 06/2012; 150(1):1–4. · 3.79 Impact Factor
  • Jian-Hui Li, Jing Jiao, Kai Jiang, Yuan-Yuan Li
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    ABSTRACT: • Premise of the study: Polymorphic microsatellite loci were developed in Torreya jackii, an endangered species in China, to provide markers for further studies on the genetic diversity of this species. • Methods and Results: Eight polymorphic loci and one monomorphic locus were developed and characterized in four T. jackii populations (Xianju, Songyang, Pujiang, and Tonglu) from Zhejiang Province, China. The number of alleles per locus ranged from one to eight across 80 T. jackii individuals. At the eight polymorphic loci, the observed heterozygosity ranged from 0.150 to 1.000 and the expected heterozygosity ranged from 0.185 to 0.796. • Conclusions: The microsatellite loci developed and characterized in this study will facilitate future analyses of the genetic diversity of T. jackii. Such information will aid in designing strategies to conserve this currently endangered species.
    American Journal of Botany 12/2011; 98(12):e349-51. · 2.59 Impact Factor
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    ABSTRACT: We developed polymorphic microsatellite primers in Castanopsis sclerophylla (Lindley & Paxton) Schottky (Fagaceae), a dominant canopy tree, to provide markers for further studies on the genetic structure and mating system of this species. Ten polymorphic microsatellite loci were isolated and successfully amplified in three C. sclerophylla populations (Huangshanjian, Shilin, and Guanmiao) from Chun'an, Zhejiang Province, China. The number of alleles per locus in these populations ranged from 3 to 17. The observed and expected heterozygosities were 0.100-0.977 and 0.294-0.916, respectively. These microsatellite loci displayed moderate or high levels of polymorphism within the examined populations, showing the utility of primers in studying the genetic variation, parentage, and mating system of C. sclerophylla.
    American Journal of Botany 02/2011; 98(2):e19-21. · 2.59 Impact Factor
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    ABSTRACT: Metasequoia glyptostroboides is an endangered plant endemic to China. Eleven polymorphic microsatellite loci were successfully isolated from M. glyptostroboides. The number of alleles per locus ranged from 2 to 6. The observed (H O) and expected (H E) heterozygosities ranged from 0.1842 to 0.8421 and 0.2389 to 0.6639, respectively. Polymorphism information content ranged from 0.2172 to 0.5901. No significant linkage disequilibrium was observed between the loci. Four loci showed significant deviations from Hardy–Weinberg equilibrium. These 11 effective primer pairs are expected to be useful for further studies on population genetics, mating system analysis, and conser-vation genetics in M. glyptostroboides. Metasequoia glyptostroboides Hu et Cheng (Taxodiaceae) is a well-known ''living fossil'' plant that is endemic to China. M. glyptostroboides has been listed as an endangered species by the Chinese government (Li et al. 2005) and a criti-cally endangered species by the International Union for Conservation of Nature (IUCN, http://www.iucnredlist.org/ search/details.php/32317/all). Since its discovery in 1940s, M. glyptostroboides has been propagated around the world and has become a common species in China, especially along the middle and lower reaches of the Yangtze River (Li et al. 2005). One goal of conservation is to recover the self-sustainability of endangered species. Genetic variation contributes to selection and recombination and is critically important to judge potential adaptation to the changing environments (Chen 2000; Lu et al. 2006). Previously, using less polymorphic allozymes or dominant random amplified polymorphic DNAs (RAPDs) and amplified fragment length polymorphisms (AFLPs), researchers found low genetic diversity in wild and artificial M. glyptostroboides popula-tions (Kuser et al. 1997; Chen et al. 2003; Li et al. 2003, 2005). Microsatellite loci are generally highly polymorphic and co-dominant and are more powerful for assessing genetic variation in organisms than allozymes and RAPDs. Here, we report on 11 polymorphic microsatellite loci isolated from M. glyptostroboides. Total genomic DNA was extracted from silica-dried leaves of M. glyptostroboides using the modified cetyltrimethylam-monium bromide (CTAB) method (Fan et al. 2004). The procedures for the construction of genomic library, enrich-ment of microsatellite-enriched library and cloning and sequencing of target fragments were as reported previously with minor modifications (Li et al. 2009; Liu et al. 2009). Microsatellite fragments were identified using 5 0 -biotin-labelled oligonucleotides (AG) 15 and (AC) 15 as probes. Consequently, 221 positive clones were sequenced using the ABI BigDye TM Terminators Cycle Sequencing kit (Applied Biosystems) on an ABI 3730 DNA Sequence Analyzer. However, 135 of the 221 sequences were dis-carded because either the repeats were too short or the flanking regions of the repeat sequences were not suitable for designing primers. Finally, 86 primer pairs flanking microsatellite regions were designed using the Primer Premier 5.0 software (http: All these microsatellite primers were tested using 38 individuals of M. glyptostroboides. Polymerase chain reac-tion (PCR) amplification was performed using an Eppendorf Mastercycler Gradient System (Eppendorf) with a 20 ll reaction volume containing 50 ng genomic DNA, 0.1 mM of each primer, 0.2 mM of each dNTP, 19 Taq buffer, 1.5 mM MgCl 2 , and 0.2 U of Taq polymerase (Sangon). The following PCR reaction was set: initial denaturation for 5 min at 95°C; followed by 35 cycles of 30 s at 94°C, 45 s at annealing temperatures depending on primers (Table 1), and 45 s at 72°C; and a final extension of 8 min at 72°C. Amplified products were separated on an 8% denaturing polyacrylamide gel and observed using silver staining. The pUC19 DNA/MspI (HpaII) ladder (Fermentas) was used to identify the alleles. Of the 86 primer pairs tested, 23 successfully amplified the target fragments in M. glyptostroboides, and 11 loci showed polymorphism. The number of alleles per locus and observed (H O) and expected (H E) heterozygosities were calculated by GENEPOP v4.0 (Rousset 2008). The number of alleles per locus varied from 2 to 6, with an average of 3.3. The observed (H O) and expected (H E) heterozygosities ranged from 0.1842 to 0.8421 and 0.2389 to 0.6639, respectively. Polymorphism information content (PIC) ran-ged from 0.2172 to 0.5901. No significant linkage disequi-librium between the loci was detected by GENEPOP v4.0 (Rousset 2008) after sequential Bonferroni correction (Rice 1989). Four loci (loci Mg01, Mg41, Mg74, and Mg77) showed significant deviation from Hardy–Weinberg equi-librium (P \ 0.05), as revealed by GENEPOP after the sequential Bonferroni correction (Rice 1989). These 11 polymorphic microsatellite loci are expected to be useful for further studies on population genetics, mating system anal-ysis, and conservation genetics in M. glyptostroboides. Acknowledgments We thank Prof. Xiao-Yong Chen for helpful comments on an early version for the manuscript. This work was sup-ported by National Natural Science Foundation of China (30700101) and Shanghai Education Commission Foundation for Excellent Young High Education Teacher of China (hsd-07023) to YY Li.
    Conservation Genetics Resources 01/2010; 2:19-21. · 1.14 Impact Factor
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    ABSTRACT: The mutualism between fig plants and fig wasps has been recognized as one of the most specialized systems of symbiosis. Figs are pollinated by their highly specific pollinating fig wasps, and the pollinating fig wasps are raised within the syconia of figs. Recent studies indicated a difference between monoecious and dioecious figs in the dispersal range of pollinating wasps, which has potential consequences for gene flow. In this study, we detected the gene-flow pattern of the dioecious climbing fig, Ficus pumila L. var. pumila, at both local and regional scales. At the local scale, spatial autocorrelation analysis indicated strong genetic structure at short distances, a pattern of limited gene flow. This result was also supported by a high inbreeding coefficient (F IS=0.287) and significant substructuring (F ST=0.060; P<0.001). Further analysis indicated that the effective gene dispersal range was 1,211m, and the relative contribution of seed dispersal was smaller than that of pollen dispersal. The inferred effective range of pollen dispersal ranged from 989 to 1,712m, while the effective seed dispersal range was less than 989m. Lack of long-distance dispersal agents may explain the limited seed dispersal. The high density of receptive fig trees was the most likely explanation for limited pollen dispersal, and the position of syconia and relatively low wind speed beneath the canopy may contribute to this phenomenon. At the regional scale, significant negative correlations (kinship coefficient F ij ranging from −0.038 to −0.071) existed in all comparisons between the studied population and other populations, and the assignment test grouped almost all individuals of the studied population into a distinct cluster. Asynchronous flowering on the regional scale, which provides a barrier for the pollinating wasps to fly from the studied population to the other populations, is probably responsible for the limited gene flow on the regional scale.
    Population Ecology 03/2009; 51(2):307-315. · 1.92 Impact Factor
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    Yuan-Yuan Li, Li-Ping Zang, Xiao-Yong Chen
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    ABSTRACT: Ginkgo biloba L. is a famous living fossil plant endemic to China. We report twelve polymorphic simple sequence repeat (SSRs) markers of G. biloba by mining expressed sequence tags (ESTs). One locus was significantly deviated from Hardy-Weinberg equilibrium. The number of alleles per locus ranged from 2 to 5. The PIC values were from 0.058 to 0.776. Observed and expected heterozygosity ranged from 0.050 to 0.776, and 0.055 to 0.799, respectively. These markers will be available for studies of population genetics, reproductive ecology and conservation genetics for G. biloba.
    Conservation Genetics Resources 01/2009; 1(1):81-83. · 1.14 Impact Factor
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    ABSTRACT:  Information on population genetics is fundamental to developing in situ or ex situ conservation strategies. Few researchers, however, have compared the genetic structure of restored and natural populations of threatened plant species. Metasequoia glyptostroboides Hu & Cheng (dawn redwood) (Taxodiaceae), a living fossil endemic to China, may be the most successfully recovered threatened species, with many more individuals and a much wider distribution than fossil records indicate. We used random amplification of polymorphic DNA markers to compare the genetic structure of artificial populations with that of wild ones and to determine whether the genetic structure of M. glyptostroboides has been recovered as has its distribution. The genetic variation of wild populations of M. glyptostroboides was lower than the average of gymnosperms, indicating the effects of glaciations and recent habitat loss and fragmentation. Genetic variation in artificial populations was less, but not substantially, compared with wild populations. The unweighted pair group method with arithmetic mean revealed that the wild and the artificial populations formed two distinct groups. Artificial populations were more similar to each other (mean Nei's genetic distance = 0.0924) than to wild populations (mean distance = 0.2054). This might be the result of biased seed collection, vegetative propagation, or a mixture of propagules from different populations and an ultimate propagule source. These results suggest that although the quantity and distribution range have been successfully restored, the genetic structure of M. glyptostroboides has not recovered appropriately, given the loss of genetic variation and biased genetic composition in artificial populations. Therefore, in addition to protecting the wild populations, additional ex situ genetic reserves should be established based on genetic knowledge and via appropriate approaches. We suggest that population genetic and demographic indices should be considered when downlisting or delisting threatened species.Resumen: Es fundamental contar con información sobre genética poblacional para el desarrollo de estrategias de conservación in situ o ex situ. Sin embargo, pocos investigadores han comparado la estructura genética de poblaciones restauradas y naturales de especies de plantas amenazadas. Metasequoia glyptostroboides Hu & Cheng (Taxodiaceae), un fósil viviente endémico de China, puede ser la especie amenazada recuperada más exitosamente, con mucho más individuos y una distribución mucho mayor que la indicada por registros fósiles. Utilizamos amplificaciones aleatorias de marcadores de ADN polimórfico para comparar la estructura genética de poblaciones artificiales con la de poblaciones silvestres y para determinar si la estructura genética de M. glyptostroboides se ha recuperado como lo ha hecho su distribución. La variación genética de poblaciones silvestres de M. glyptostroboides fue menor que la del promedio de gimnospermas, lo que indica efectos de glaciaciones y pérdida y fragmentación reciente de hábitat. La variación genética en poblaciones artificiales fue menor, pero no sustancialmente, comparada con poblaciones silvestres. El método de grupos pareados con media aritmética reveló que las poblaciones artificiales y silvestres formaron dos grupos distintos. Las poblaciones artificiales fueron más similares entre si (distancia genética de Nei promedio = 0.0924) que con poblaciones silvestres (distancia promedio = 0.2054). Esto puede ser el resultado de la colecta sesgada de semillas, propagación vegetativa o mezcla de propágulos de diferentes poblaciones y una fuente terminal de propágulos. Estos resultados sugieren que aunque la cantidad y la distribución se han restaurado exitosamente, la estructura genética de M. glyptostroboides no se ha recuperado adecuadamente, dada la pérdida de variación genética y la composición genética sesgada de poblaciones artificiales. Por lo tanto, además de proteger a las poblaciones silvestres, se deben establecer reservas genéticas ex situ adicionales con base en conocimiento genético y por medio de métodos adecuados. Sugerimos que se deben considerar índices demográficos y de genética poblacional cuando se revise el estatus de especies amenazadas.
    Conservation Biology 01/2005; 19(1):224 - 231. · 4.36 Impact Factor
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    ABSTRACT: The genetic composition of Poa annua L. populations with a series of traffic pollution was studied by starch electrophoresis. Five enzyme systems were stained. The results showed that: (1) Traffic pollution can dramatically change genotypic frequencies at some loci of P. annua populations. Significant deviations from Hardy-Weinberg equilibrium were observed on loci Fe-1 and Me due to the excess of heterozygotes in some populations. (2) The effective number of alleles per locus and the observed and expected heterozygosity were higher in the pollution series than in the clear control site (Botanic Park population), but the increase was not related with the pollution extent. (3) Most genetic variation was found within populations, and only 6.21% was among populations of the polluted series. Slightly higher differentiation (FST = 7.98%) was observed when the control population was included. (4) The calculated gene flow (Nm) is 2.8841 per generation. The mean of genetic identity is 0.9864 and the genetic distance average to 0.0138.
    Journal of Environmental Sciences 02/2004; 16(3):454-7. · 1.77 Impact Factor
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    Xiao-yong Chen, Ning Li, Lang Shen, Yuan-yuan Li
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    ABSTRACT: The population genetic composition of Poa annua L. was studied by starch electrophoresis along a transect running NE from an organic reagents factory at Shanghai, China. Five enzyme systems were stained. We have reached the following preliminary conclusions: (1). Organic pollution has dramatically changed genotypic frequencies at some loci of Poa annua populations. At polluted sites, significant deviations from Hardy-Weinberg equilibrium were observed on loci Sod-1 and Me due to the excess of heterozygote. Especially in the two nearest sites to pollution source, all the individuals were heterozygous at locus Sod-1. The data suggests that heterozygotes were more tolerant to organic pollution than homozygotes, indicating the fitness superiority of heterozygotes. (2). A tendency towards clinal changes of allele frequencies was found at some polymorphic loci. Frequencies of the common alleles at loci Sod-1, Me and Fe-1 increased as the distance to the pollution source increased. (3). The effective number of alleles per locus, and the observed and expected heterozygosity were much higher in the pollution series than in the clear control site (Botanic Park population), but genetic multiplicity (number of alleles per locus) was lower than for the control. (4). Most genetic variability was found within populations, and only 2.56% were among populations of the polluted series. However, 9.48% of the total genetic variation occurred among populations when including the Botanic Park population. The genetic identity between populations of the pollution series (0.9869-1.0000, mean 0.9941) was higher than those between the pollution series and the Botanic Park population. UPGMA divided the five populations into two groups. One contained the four polluted populations, and the other only contained the Botanic Park population.
    Environmental Pollution 02/2003; 124(3):449-55. · 3.73 Impact Factor
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    ABSTRACT: Many endangered species have small population sizes, with less than 10 remaining individuals in some extreme situations. Although the consequences of a small population size have received considerable research attention, few studies have examined the fate of extremely rare plants. Ostrya rehderiana is one such species, with only 5 naturally-regenerated surviving individuals and less than 150 artificially-regenerated progeny. Using amplified fragment length polymorphisms (AFLPs), we found that there was a low percentage of polymorphic loci but moderate heterozygosity in the 5 wild individuals. A severe decline in genetic diversity was observed in the progeny, with a decrease of 36.7% in heterozygosity and of 12% in the number of markers that were amplified per individual compared with the parental generation, a result which was caused by genetic drift and inbreeding. The effective population size was estimated to be 1. A significant positive relationship between parental genetic dissimilarity and the number of surviving offspring was observed, which indicated that inbreeding depression might have purged more inbred offspring. Implications for protection and recovery of the genetic variation of extremely rare plants, such as O. rehderiana, are proposed.
    Conservation Genetics 13(2). · 2.18 Impact Factor