scholarly journals Genetic diversity and spatial genetic structure within a population of an aromatic shrub, Lippia origanoides (Verbenaceae), in the Chicamocha Canyon, northeastern Colombia

2008 ◽  
Vol 90 (6) ◽  
pp. 455-465 ◽  
Author(s):  
ADRIANA SUÁREZ G. ◽  
GENIS CASTILLO ◽  
MARIA I. CHACÓN S.

SummaryThe geographical scale of genetic structure in a continuous population is highly dependent on its breeding system and dispersion capabilities, and this knowledge is important for the study of population dynamics as well as for conservation purposes. In the present study, spatial autocorrelation statistics and intersimple sequence repeat (ISSR) markers were used to describe the genetic structure of a natural population of a prominent aromatic plant, Lippia origanoides, native to the Chicamocha Canyon in northeastern Colombia. For this purpose, individuals were sampled from two localities within the Chicamocha Canyon, where the species is abundant and continuously distributed. Cluster (principal coordinate analysis (PCO) and unweighted pair group method using arithmetic averages (UPGMA)), analysis of molecular variance (AMOVA) and Bayesian analyses revealed a low level of genetic differentiation among the two localities, suggesting that they belong to a single population. Genetic diversity levels in this population, described as the percentage of polymorphic loci (P=86·21%) and quantified using Shannon's diversity index (I=0·453) and the average panmictic heterozygosity (HB=0·484), were shown to be comparable to or higher than that in other plant species with allogamous breeding systems and to other related Verbenaceae species. Fine-scale autocorrelation analyses showed a pattern consistent with the classical model of isolation by distance with moderate but significant levels of local spatial structure. Our results suggest that sampling individuals at distances greater than ~1·2 km may result in the collection of different genotypes, which could help preserve the levels of genetic diversity in a propagation programme. The causes of this spatial pattern are currently unknown and could be influenced by many contemporary factors such as restricted seed dispersal and/or short-distance pollen movement, among others.

2008 ◽  
Vol 88 (2) ◽  
pp. 313-322 ◽  
Author(s):  
S. C. Debnath ◽  
S. Khanizadeh ◽  
A. R. Jamieson ◽  
C. Kempler

The goal of this study was to determine the level of genetic diversity and relatedness among 16 strawberry (Fragaria H ananassa Duch.) cultivars and 11 breeding lines developed in Canada, using Inter Simple Sequence Repeat (ISSR) markers. Seventeen primers generated 225 polymorphic ISSR-PCR bands. Cluster analysis by the unweighted pair-group method with arithmetic averages (UPGMA) revealed a substantial degree of genetic similarity among the genotypes ranging from 63 to 77% that were in agreement with the principal coordinate (PCO) analysis. Geographical distribution for the place of breeding program explained only 1.4% of total variation as revealed by analysis of molecular variance (AMOVA). The ISSR markers detected a sufficient degree of polymorphism to differentiate among strawberry genotypes, making this technology valuable for cultivar identification and for the more efficient choice of parents in current strawberry breeding programs. Key words: Fragaria × ananassa, DNA fingerprinting, multivariate analysis, breeding, genetic similarity


2013 ◽  
Vol 21 (1) ◽  
pp. 83-89 ◽  
Author(s):  
Saida Sharifova ◽  
Sabina Mehdiyeva ◽  
Konstantinos Theodorikas ◽  
Konstantinos Roubos

Abstract Random Amplified Polymorphic DNA (RAPD) analysis was carried out on 19 Azerbaijan tomato genotypes, both cultivars and local populations. A total of 26 amplified products were revealed by 6 primers. The genetic similarity among evaluated genotypes ranged from 0.188 to 1.000. The lowest similarity was observed between cultivars ‘Azerbaijan’ and ‘Shakar’ (0.188), while the highest between ‘Elnur’ and ‘Garatag’ (1.000). The Unweighted Pair Group Method with Arithmetic Mean (UPGMA) cluster analysis based on Jaccard’s similarity coefficient divided genotypes into four main groups. The first group was the largest and consisted of 12 genotypes, while the fourth group was the smallest consisted of 1 genotype only. The most polymorphic primer was OPB-18 that presented a genetic diversity index of 0.823, while the least informative was primer OPG-17 with an index of 0.349. The average genetic diversity calculated from RAPD data was 0.665.


2021 ◽  
Vol 10 (16) ◽  
pp. e187101623025
Author(s):  
Daniele Paula Maltezo ◽  
Julliane Dutra Medeiros ◽  
Ana Aparecida Bandini Rossi

The Amazon is the largest tropical forest in the world and is home to around 20% of all the biodiversity on the planet, among the species present in the Amazon is Copaifera langsdorffii, exploited mainly for the extraction of oil-resin and wood, often in ways incorrect, which can cause the loss of genetic variability. The aim of this study was to evaluate the genetic structure and diversity among individuals of C. langsdorffii located in Mato Grosso, Brazil, using ISSR markers. We sampled leaves from 27 adult individuals of C. langsdorffii, whose total genomic DNA was extracted. A total of 12 ISSR primers were used for the molecular characterization of the individuals. A grouping analysis was performed using the unweighted pair group method, Bayesian analysis and characterized by the genetic diversity. The genetic diversity among and within the groups was demonstrated by the AMOVA. As a result, 106 fragments were amplified and 98.11% were polymorphic. The polymorphic information content of each primer ranged from 0.45 to 0.81.  The dendrogram showed the formation of 4 distinct groups. The greatest genetic variability is found within the groups and not between them. The percentage of polymorphism, genetic dissimilarity values and genetic diversity indexes indicate that there is high genetic variability among Copaifera langsdorffii individuals, suggesting that ISSR primers were efficient in detecting polymorphism in this species and that the individuals have potential for compose programs aimed at the preservation of the species and the ability to integrate germplasm banks.


2015 ◽  
Vol 13 ◽  
pp. 17-30 ◽  
Author(s):  
Agnieszka Sutkowska ◽  
Kesara Anamthawat-Jónsson ◽  
Borgthór Magnússon ◽  
Wojciech Bąba ◽  
Józef R. Mitka

Prior to the present study there was limited knowledge about the genetic basis of plant colonization on the 50-year-old island of Surtsey, South Iceland. The aim here was to compare genetic structure of two contrasting species, Festuca rubra (arctic fescue) and Empetrum nigrum (crowberry), which have colonized Surtsey since 1973 and 1993, respectively. Inter-simple sequence repeat (ISSR) markers were used to assess genetic diversity and population structure. Two census periods were compared: 1996-1997 and 2005-2006. Using six ISSR primers, we obtained 103 and 139 discernible DNA fragments from F. rubra and E. nigrum respectively. Although the two species displayed similarly high genetic diversity indices (h = 0.238 and 0.235; I = 0.384 and 0.380, respectively), they differed significantly in their genetic profiles. Festuca was genetically structured at the subpopulation level (FST = 0.034, p = 0.007), whereas Empetrum showed a lack of genetic differentiation. A Bayesian STRUCTURE computation further revealed temporal and spatial genetic structure of the species. The early arrival grass F. rubra has expanded from a local genepool. The population was however initially established from different sources, forming a genetic melting pot on Surtsey. On the other hand, the late arrival shrub E. nigrum probably derived from a common source of immigrants.


2020 ◽  
Vol 68 (5) ◽  
pp. 384
Author(s):  
William Higgisson ◽  
Dianne Gleeson ◽  
Linda Broadhurst ◽  
Fiona Dyer

Gene flow is a key evolutionary driver of spatial genetic structure, reflecting demographic processes and dispersal mechanisms. Understanding how genetic structure is maintained across a landscape can assist in setting conservation objectives. In Australia, floodplains naturally experience highly variable flooding regimes that structure the vegetation communities. Flooding plays an important role, connecting communities on floodplains and enabling dispersal via hydrochory. Water resource development has changed the lateral-connectivity of floodplain-river systems. One possible consequence of these changes is reduced physical and subsequent genetic connections. This study aimed to identify and compare the population structure and dispersal patterns of tangled lignum (Duma florulenta) and river cooba (Acacia stenophylla) across a large inland floodplain using a landscape genetics approach. Both species are widespread throughout flood prone areas of arid and semiarid Australia. Tangled lignum occurs on floodplains while river cooba occurs along rivers. Leaves were collected from 144 tangled lignum plants across 10 sites and 84 river cooba plants across 6 sites, on the floodplain of the lower and mid Lachlan River, and the Murrumbidgee River, NSW. DNA was extracted and genotyped using DArTseq platforms (double digest RADseq). Genetic diversity was compared with floodplain-river connection frequency, and genetic distance (FST) was compared with river distance, geographic distance and floodplain-river connection frequency between sites. Genetic similarity increased with increasing floodplain-river connection frequency in tangled lignum but not in river cooba. In tangled lignum, sites that experience more frequent flooding had greater genetic diversity and were more genetically homogenous. There was also an isolation by distance effect where increasing geographic distance correlated with increasing genetic differentiation in tangled lignum, but not in river cooba. The distribution of river cooba along rivers facilitates regular dispersal of seeds via hydrochory regardless of river level, while the dispersal of seeds of tangled lignum between patches is dependent on flooding events. The genetic impact of water resource development may be greater for species which occur on floodplains compared with species along river channels.


2006 ◽  
Vol 86 (1) ◽  
pp. 251-257 ◽  
Author(s):  
Zhao Weiguo ◽  
Zhou Zhihua ◽  
Miao Xuexia ◽  
Wang Sibao ◽  
Zhang Lin ◽  
...  

The genetic diversity of 27 mulberry (Morus spp.) genotypes mainly from China was investigated using inter-simple sequence repeat (ISSR) markers to assist in addressing breeding objectives and conserving existing genetic resources. Of the 22 primers screened, 15 produced highly reproducible ISSR bands. Using these 15 primers, 138 discernible DNA fragments were generated with 126 (91.3%) being polymorphic, indicating considerable genetic variation among the mulberry genotypes studied. Genetic similarity ranged from 0.6014 between Yu 2 and Yu 711 to 0.9493 between Cuizhisang and Dejiang 10. The phenetic dendrogram based on ISSR data generated by the unweighed pair group method with arithmetical averages (UPGMA) method grouped the 27 accessions into two major clusters: cluster I, cultivated mulberry species (M. multicaulis Perr., M. alba Linn., M. atropurpurea oxb., M. bombycis Kiodz., M. australis Poir., M. rotundiloba Kiodz., M. alba var. pendula Dipp., M. alba var. macrophylla Loud., and M. alba var. venose Delile.); and cluster II, wild mulberry species (M. cathayana Hemsl., M. laevigata Wall., M. wittiorum Hand-Mazz., M. nigra Linn., and M. mongolica Schneid.). Our molecular analyses agree with the existing morphological classification of Morus and clarify the genetic relationships among mulberry species. Key words: Morus L., genetic diversity, inter-simple sequence repeat, relatedness


AoB Plants ◽  
2020 ◽  
Author(s):  
Rong Huang ◽  
Zong-Dian Zhang ◽  
Yu Wang ◽  
Ying-Qiang Wang

Abstract Habitat fragmentation strongly affects the genetic diversity of plant populations, and this has always attracted much research interest. Although numerous studies have investigated the effects of habitat fragmentation on the genetic diversity of plant populations, fewer studies have compared species with contrasting breeding systems while accounting for phylogenetic distance. Here, we compare the levels of genetic diversity and differentiation within and among subpopulations in metapopulations (at fine-scale level) of two closely related Zingiber species, selfing Zingiber corallinum and outcrossing Zingiber nudicarpum. Comparisons of the genetic structure of species from unrelated taxa may be confounded by the effects of correlated ecological traits or/and phylogeny. Thus, we possibly reveal the differences in genetic diversity and spatial distribution of genetic variation within metapopulations that relate to mating systems. Compared to outcrossing Z. nudicarpum, the subpopulation genetic diversity in selfing Z. corallinum was significantly lower, but the metapopulation genetic diversity was not different. Most genetic variation resided among subpopulations in selfing Z. corallinum metapopulations, while a significant portion of variation resided either within or among subpopulations in outcrossing Z. nudicarpum, depending on whether the degree of subpopulation isolation surpass the dispersal ability of pollen and seed. A stronger spatial genetic structure appeared within subpopulations of selfing Z. corallinum potentially due to restricted pollen flow and seed dispersal. In contrast, a weaker genetic structure was apparent in subpopulations of outcrossing Z. nudicarpum most likely caused by extensive pollen movement. Our study shows that high genetic variation can be maintained within metapopulations of selfing Zingiber species, due to increased genetic differentiation intensified primarily by the stochastic force of genetic drift among subpopulations. Therefore, maintenance of natural variability among subpopulations in fragmented areas is key to conserve the full range of genetic diversity of selfing Zingiber species. For outcrossing Zingiber species, maintenance of large populations is an important factor to enhance genetic diversity.


Botany ◽  
2012 ◽  
Vol 90 (3) ◽  
pp. 167-174
Author(s):  
Lin Meng ◽  
Xiaoyan Zhang ◽  
Peichun Mao ◽  
Xiaoxia Tian

The genetic diversity among 30 accessions of Elytrigia repens (L.) Nevski was analyzed using 100 intersimple sequence repeat (ISSR) primers, 12 of which generated distinct amplification products. Out of the 132 repeatable bands detected, 100 bands were polymorphic. The percentage of polymorphic bands was 70.66%, with a mean of 8.33 percentage of polymorphic bands per primer. The ISSR-based genetic similarity coefficients among the 30 accessions ranged from 0.509 to 0.873, revealing high genetic diversity. The 30 E. repens accessions were divided into eight groups based on an unweighted pair-group method with arithmetic mean cluster analysis and a principal components analysis. We found that genetic distance is correlated with geographical distance among the 30 E. repens accessions studied (r = 0.812, p < 0.05) using Mantel’s test. Our results confirm the potential value of genetic diversity preservation for future breeding programs.


2011 ◽  
Vol 77 (8) ◽  
pp. 2596-2601 ◽  
Author(s):  
Helvécio D. Coletta-Filho ◽  
Leonora S. Bittleston ◽  
Rodrigo P. P. Almeida

ABSTRACTVector-borne generalist pathogens colonize several reservoir species and are usually dependent on polyphagous arthropods for dispersal; however, their spatial genetic structure is generally poorly understood. Using fast-evolving genetic markers (20 simple sequence repeat loci, resulting in a total of 119 alleles), we studied the genetic structure of the vector-borne plant-pathogenic bacteriumXylella fastidiosain Napa Valley, CA, where it causes Pierce's disease when it is transmitted to grapevines from reservoir plants in adjacent riparian vegetation. Eighty-three differentX. fastidiosamultilocus microsatellite genotypes were found in 93 isolates obtained from five vineyards, resulting in an index of clonal fraction closer to 0 and a Simpson's genotypic diversity index (D) closer to a maximum value of 1. Moderate values of Nei's gene diversity (HNei; averageHNei= 0.41) were observed for most of theX. fastidiosapopulations. The low Wright's index of genetic diversity among populations calculated by the FSTAT software (Wright'sFSTindex) among population pairs (0.0096 to 0.1080) indicated a weak or absent genetic structure among the five populations; a panmictic population was inferred by Bayesian analyses (with the STRUCTURE and BAPS programs). Furthermore, a Mantel test showed no significant genetic isolation by distance when both Nei (r= −0.3459,P= 0.268) and linearized θ (r= −0.3106,P= 0.269) indices were used. These results suggest that the riparian vegetation from which vectors acquire the pathogen prior to inoculation of grapevines supports a diverse population ofX. fastidiosa.


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. *********


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