The population genetic structure and diversification of Aristolochia delavayi (Aristolochiaceae), an endangered species of the dry hot valleys of the Jinsha River, southwestern China

Botany ◽  
2014 ◽  
Vol 92 (8) ◽  
pp. 579-587 ◽  
Author(s):  
Zhi-Yun Yang ◽  
Ting-Shuang Yi ◽  
Liang-Qin Zeng ◽  
Xun Gong

Aristolochia delavayi Franch. is an endangered species of the dry hot valleys of the Jinsha River, southwestern China. The genetic diversity and structure of the species and the occurrence of gene flow were investigated with eight inter-simple sequence repeat (ISSR) markers and four plastid loci (matK, trnL-trnT, rps4-trnT, and trnC-rpoB). The analysis of ISSR markers indicated that the genetic diversity of the species is relatively high (PPB = 84.71%). Similarly, a high gene diversity of HT = 0.833 was found based on the four plastid loci. It is possible that this species previously maintained a large effective population size and that the current relict distribution of the species is a result of large-scale fragmentation and habitat destruction. The origin of the species at approximately 3.407 million years ago and the ensuing intraspecific divergence are generally consistent with the history of two major glaciations in this region. Conservation measures are urgently needed to increase the genetic diversity and population size of this species through both in- and ex-situ action.

2021 ◽  
Vol 12 ◽  
Author(s):  
Yuliang Jiang ◽  
Tsam Ju ◽  
Linda E. Neaves ◽  
Jialiang Li ◽  
Weining Tan ◽  
...  

Population genetic assessment is crucial for the conservation and management of threatened species. Xanthocyparis vietnamensis is an endangered species that is currently restricted to karst mountains in southwestern China and Vietnam. This rare conifer was first recorded in 2002 from northern Vietnam and then in 2013 from Guangxi, China, yet nothing is known about its genetic diversity nor ploidy level variation, although previous cytological study suggest that Vietnamese populations are tetraploids. There have been about 45 individuals found to date in Guangxi, China. Here, we genotyped 33 X. vietnamensis individuals using 20 newly developed, polymorphic microsatellite loci, to assess the genetic variability of its extremely small populations. The genetic diversity of X. vietnamensis (HE = 0.511) was lower than that of two other heliophile species, Calocedrus macrolepis and Fokienia hodginsii, which have similar distribution ranges. This is consistent with the signature of a genetic bottleneck detected in X. vietnamensis. Although the population genetic differentiation coefficient across loci is moderate (FST = 0.125), STRUCTURE analysis revealed two distinct genetic clusters, namely the northern and southern population groups; DAPC analysis grouped the southern populations together in one cluster separate from the northern populations; AMOVA analysis detected a significant genetic differentiation between the two population groups (FRT = 0.089, p < 0.05), and BARRIER analysis detected a genetic barrier between them. Moreover, we detected differentiation in ploidy level between northern and southern populations, sampled individuals from the former and the later are all diploid and tetraploid cytotypes with mean genome sizes of 26.08 and 48.02 pg/2C, respectively. We deduced that heterogeneous geomorphology and historical events (e.g., human deforestation, Quaternary climate oscillations) may have contributed to population fragmentation and small population size in X. vietnamensis. Considering both genetic and ploidy level differentiation, we propose that two different management units (northern and southern) should be considered and a combination of in situ and ex situ conservation measures should be employed to preserve populations of this endangered species in southwestern China in the light of our findings.


2007 ◽  
Vol 132 (4) ◽  
pp. 501-506 ◽  
Author(s):  
Basilio Carrasco ◽  
Marcelo Garcés ◽  
Pamela Rojas ◽  
Guillermo Saud ◽  
Raúl Herrera ◽  
...  

The chilean strawberry displays high fruit quality and tolerance to abiotic and biotic factors. Additionally, this species has a rich cultural history going back for at least several thousand years in association with aboriginal people activities and continues at a reduced level today. After its introduction to Europe during the 18th century, it formed an interspecific hybrid to become the maternal species of the commercial strawberry, Fragaria ×ananassa Duch. The objectives of the current investigation were to determine the level and patterns of partitioning of intersimple sequence repeat (ISSR) diversity. ISSR markers were used to assess the genetic diversity in 216 accessions of F. chiloensis, which represented the two botanical forms present in Chile [F. chiloensis ssp. chiloensis f. chiloensis and F. chiloensis ssp. chiloensis f. patagonica (L.) Duch.]. Our results showed high genetic diversity at the species level [polymorphic ISSR loci (P) = 89.6%, gene diversity (h) = 0.24 ± 0.17, Shannon's index (S) = 0.37 ± 0.24] and a lower genetic diversity in f. chiloensis than f. patagonica. The analysis of molecular variance (AMOVA) showed a moderate genetic differentiation among accessions (φst = 14.9%). No geographic patterns for ISSR diversity were observed. AMOVA, structure, and discriminant analysis indicated that accessions tend to group by botanical form. The impact of domestication on the genetic structure of chilean strawberry and its application to breeding and conservation are discussed.


2019 ◽  
Vol 47 (4) ◽  
pp. 1308-1315
Author(s):  
Peng-Li ZHENG ◽  
Jian-Ru CHENG ◽  
Long-Qing CHEN ◽  
Ming-Qin ZHOU

Investigation on the level and pattern of genetic diversity of 10 natural populations of the endangered species Fraxinus hupehensis using inter-simple sequence repeat (ISSR) markers was crucial for understanding the structure of the population and assessing the best genetic protection strategies. A total of 180 polymorphic bands with the polymorphic rate of 100.00% were amplified by 14 primers. The genetic diversity at population level (Percentage of polymorphic loci, PPL=64.06; Nei’s gene diversity index, h=0.1519; Shannon’s information index, I=0.2434) was lower than that at species level (PPL= 100.00%, h=0.1833, I=0.3041). Analysis of molecular variance (AMOVA) demonstrated the low level of the genetic variation occurred between the populations (16.05%). This also can be corroborated by the gene flow (Nm 2.424) and the coefficient of gene differentiation (Gst=0.1710) among populations. Cluster analysis based on the unweighted pair group method with arithmetic averages (UPGMA) revealed four groups for 10 populations according to Nei’s genetic identity and seven categories for the 196 individuals according to SM values. Furthermore, the endangered mechanism and genetic structure of F. hupehensis were discussed, and appropriate targeted protection measures were proposed based on these findings.   ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 4, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********


2016 ◽  
Vol 68 (3) ◽  
pp. 669-675
Author(s):  
Yancai Shi ◽  
Xiao Wei ◽  
Jiqing Wei ◽  
Yongtao Li ◽  
Shengfeng Chai ◽  
...  

Heteroplexis microcephala Y. L. Chen. is an endemic and endangered species found only in karst limestone regions in the Yangshuo County of the Guangxi Zhuang Autonomous Region in China: it is a habitat representative of species in the Heteroplexis genus. To provide basic genetic information for its conservation, in this study we evaluated the genetic variation and differentiation among six wild populations of H. microcephala by random amplified polymorphic DNA markers (RAPD). The leaves of 141 individuals were sampled. Based on 12 primers, 113 DNA fragments were generated. Genetic diversity was low at the population level (Nei?s gene diversity (h)=0.0579; Shannon information index (I)=0.0924; percentage of polymorphic bands (PPB)=23.30%), but relatively high at the species level (h=0.1701; I=0.2551; PPB=46.34%). The coefficient of genetic differentiation based on Nei?s genetic diversity analysis (0.6661) was high, indicating that there was significant genetic differentiation among populations, which was confirmed by AMOVA analysis exhibiting population differentiation among populations of 68.77%. Low gene flow among populations (0.2507) may result from several factors, such as a harsh pollination environment, population isolation and low seed dispersal distance. Limited gene flow and self-compatibility are the primary reasons for the high genetic differentiation observed for this species. We propose the collection of seeds from more populations with fewer individuals and core populations for ex situ conservation and suggest methods to increase seed germination rates.


2021 ◽  
Vol 25 (03) ◽  
pp. 683-691
Author(s):  
Ahmed A. Qahtan

The success of breeding programs depends on the extent of genetic variability. Inter-simple sequence repeats (ISSR) have been widely utilized in investigations, including the characterization of many plant species genetically. This research aimed to examine both the genetic diversity and relationships of 92 faba bean (Vicia faba L.) genotypes from different geographical areas using ISSR markers. Eleven ISSR primers generated a total of 189 repeatable amplified bands, of which 109 were polymorphic. Values of polymorphism information content (PIC) and gene diversity averaged 0.3484 and 0.1438 and ranged 0.089–0.715 and 0.0742–0.2065, respectively. The studied accessions of faba bean plant differentiated into four main clusters, prevalently based on geographical origin through UPGMA clustering analysis and principal component analysis (PCA), deriving four major groupings based on pedigree and origin relationships. The STRUCTURE software analysis results were significantly aligned with the PCA and showed five main clusters; each one represents one continent. AMOVA showed high variation and differentiation among nations from different continents. The discrimination power of ISSR markers obtained in this study suggests that they could be used to examine the diversity of faba bean genotypes efficiently and precisely and encourage targeted crossing strategies. © 2021 Friends Science Publishers


Genetika ◽  
2018 ◽  
Vol 50 (1) ◽  
pp. 59-68
Author(s):  
Jalal Rezaei ◽  
Zare Mehrjerdi ◽  
Hassan Mastali

Melanocrommyum, a subgenus of the Allium genus, is found in different regions of Iran and is in danger of extinction due to excessive exploitation. This study aimed to determine the genetic diversity in 170 individuals representing 17 wild populations belonging to six endangered species of Allium subg. Melanocrommyum using inter simple sequence repeat (ISSR) markers. The 10 selected ISSR primers produced 178 polymorphic fragments (100%). Polymorphic band number varied from 12 (primer 8) to 22 (primer 2). The average observed number of alleles, effective number of alleles, Shannon?s indices and Nei?s gene diversity were 1.48, 1.2, 0.2 and 0.1, respectively. According to Nei?s genetic distance, the lowest genetic distance (0.048) was observed among both two populations of A. elburzense (Emamzadeh Ebrahim and Kamelat), and two populations of A. subakaka (Jame Shoran and Ghalelan) while the highest distance (0.097) was observed among a population of A. kurdistanicum (Taze Abad Oryeh) with both A. pseudobodeanum (Shen Jari), and A. derderianum (Dareh Oson) populations. In UPGMA cluster analysis, the populations were grouped into four main clusters at a cutoff value of 0.07. The analysis of molecular variance showed that the maximum value of genetic variation was found within the populations (68%), where as a low genetic differentiation was observed among the populations (32%). Our results revealed that ISSR molecular markers are useful to display the diversity in Allium genus and can be used to improve the classification accuracy. This study provided valuable information for the conservation of these species and breeding program planning.


1970 ◽  
Vol 7 ◽  
pp. 56-63 ◽  
Author(s):  
Chunlin Long ◽  
Zhutan Jiang ◽  
Zhiling Dao

Ottelia acuminata (Gagnep.) Dandy (Hydrocharitaceae), an endangered aquatic species, was investigated in the Eastern Himalayas, especially in Yunnan Province of Southwest China. The genetic diversity among seven populations was examined using inter-simple sequence repeat (ISSR) amplification markers. The field survey showed that 43.5% natural populations of O. acuminata have become extinct during the last 30 years. Among 13 remaining wild populations, eight (61.5%) are on the edge of extinction and only five (38.5%) were unaffected. For the study on seven populations based on ten primers, 147 clear and reproducible DNA fragments were generated, of which 144 (97.96%) were polymorphic. Within populations, however, the polymorphic bands (PPB) generated by ISSRs was 53 and occupied 36.05% in population B, and similarly within population J (51 and 34.69%, respectively). The results showed that genetic variation is much higher among populations of O. acuminata than within populations. Analyses of Nei’s gene diversity, genetic distance and Shannon’s index also agreed with these results. The average value of Nei’s gene diversity (h) equaled 0.3710. The coefficient of genetic differentiation (Gst) equaled 0.5487, which means that 54.87% of the total molecular variance existed among populations. Such a high level of divergence present among populations may be caused by the complex topography and separated habitats which effectively restrict gene flow. Moreover, there is a lack of significant association between genetic and geographical distances (r = 0.28889, P > 0.05) in the populations of O. acuminata. Therefore, we proposed an appropriate strategy for conserving the genetic resources of O. acuminata in the Eastern Himalayas; namely, rescuing and conserving the core populations in situ, while selecting and preserving more populations with fewer individuals from each population ex situ. Key-words: Ottelia acuminata, genetic diversity, conservation, Eastern Himalayas, Yunnan Plateau, China DOI: 10.3126/botor.v7i0.4374Botanica Orientalis – Journal of Plant Science (2010) 7: 56-63


2021 ◽  
Vol 43 (1) ◽  
pp. 38-42
Author(s):  
Kavungal Priya ◽  
◽  
Indira . ◽  
Vadakkethil Balakrishnan Sreekumar ◽  
Renuka . ◽  
...  

Calamus brandisii Becc. is one of the endemic slender rattans found in the Western Ghats of India. The genetic diversity of two main populations available in Kerala was investigated using 20 RAPD and 9 ISSR markers. Two parameters viz., gene diversity and genetic diversity within and among populations were analyzed. ISSR analysis showed quite high genetic diversity in Pandimotta compared to Bonacaud population whereas in RAPD markers both these populations were moderately diverse. The percentage of total genetic differentiation (Gst) among two populations is relatively higher than the mean Gst value indicating high genetic diversity within the populations. The genetic distance between these two populations was 0.1739 with ISSR markers and 0.1971 with RAPD markers. Because of its high genetic diversity, Pandimotta population can be treated as an important population of gene diversity with potentially useful genes. This may be included in the high priority reservoir for genetic conservation also.


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