Genetic diversity in Tunisian rosy garlic populations (Allium roseum L.) as evidenced by chloroplastic DNA analysis: Sequence variation of non-coding region and intergenic spacers

2010 ◽  
Vol 38 (4) ◽  
pp. 502-509 ◽  
Author(s):  
Arbi Guetat ◽  
Roser Vilatersana ◽  
Mohamed Neffati ◽  
Mohamed Boussaid
2002 ◽  
Vol 78 (4) ◽  
pp. 539-549 ◽  
Author(s):  
Paul D Anderson ◽  
John C Zasada ◽  
Glen W Erickson ◽  
Zigmond A Zasada

A white pine (Pinus strobus L.) stand at the western margin of the species range, approximately 125 years of age at present, was thinned in 1953 from 33.5 m2 ha-1 to target residual basal areas of 18.4, 23.0, 27.5, and 32.1 m2 ha-1 . Repeated measurement over the following 43-years indicated that the greatest total volume production and the greatest number of large diameter trees occurred in the unit of highest residual density. Over time, the distribution of stems was predominantly random although mortality between 1979 and 1996 resulted in a tendency for clumping in the 23.0 and 27.5 m2 ha-1 treatments. DNA analysis indicated that thinning intensity had little effect on the genetic diversity of residual white pine. This study suggests that mature white pine stands in northern Minnesota may be managed at relatively high densities without loss of productivity. However, regardless of overstory density, there was little or no white pine regeneration occurring in this stand. Key words: thinning, growth, genetic diversity, molecular markers, spatial pattern, regeneration


2013 ◽  
Vol 13 (2) ◽  
pp. 73-78
Author(s):  
Jarina Joshsi ◽  
Lumanti Manandhar ◽  
Patima Shrestha ◽  
Rani Gupta ◽  
Rojlina Manadhar ◽  
...  

Random amplified polymorphic DNA (RAPD) markers were used to study genetic diversity in dog samples belonging to populations of German Shepherd and Japanese Spitz. A total of twelve samples were typed using eight RAPD primers. Out of eight primers, three primers gave result in six individuals of dogs. The phylogenetic tree constructed by the neighbor joining method based on Nei. Original measures revealed highest genetic identity found in German Shepherd as 0.9444 and highest genetic distance as 1.2809. The analysis predicts the number of polymorphic loci as 15 and the percentage of polymorphic loci as 83.3. Nepal Journal of Science and Technology Vol. 13, No. 2 (2012) 73-78 DOI: http://dx.doi.org/10.3126/njst.v13i2.7717


2005 ◽  
Vol 86 (8) ◽  
pp. 2175-2183 ◽  
Author(s):  
Greta Jerzak ◽  
Kristen A. Bernard ◽  
Laura D. Kramer ◽  
Gregory D. Ebel

Intrahost genetic diversity was analysed in naturally infected mosquitoes and birds to determine whether West Nile virus (WNV) exists in nature as a quasispecies and to quantify selective pressures within and between hosts. WNV was sampled from ten infected birds and ten infected mosquito pools collected on Long Island, NY, USA, during the peak of the 2003 WNV transmission season. A 1938 nt fragment comprising the 3′ 1159 nt of the WNV envelope (E) coding region and the 5′ 779 nt of the non-structural protein 1 (NS1) coding region was amplified and cloned and 20 clones per specimen were sequenced. Results from this analysis demonstrate that WNV infections are derived from a genetically diverse population of genomes in nature. The mean nucleotide diversity was 0·016 % within individual specimens and the mean percentage of clones that differed from the consensus sequence was 19·5 %. WNV sequences in mosquitoes were significantly more genetically diverse than WNV in birds. No host-dependent bias for particular types of mutations was observed and estimates of genetic diversity did not differ significantly between E and NS1 coding sequences. Non-consensus clones obtained from two avian specimens had highly similar genetic signatures, providing preliminary evidence that WNV genetic diversity may be maintained throughout the enzootic transmission cycle, rather than arising independently during each infection. Evidence of purifying selection was obtained from both intra- and interhost WNV populations. Combined, these data support the observation that WNV populations may be structured as a quasispecies and document strong purifying natural selection in WNV populations.


2020 ◽  
Vol 37 (5) ◽  
pp. 1
Author(s):  
Wakana Harigai ◽  
Aya Saito ◽  
Hitoshi Suzuki ◽  
Masanobu Yamamoto

2013 ◽  
Vol 5 (1) ◽  
pp. 114-119 ◽  
Author(s):  
Özlem ÖZBEK ◽  
Betül Uçar GIDIK

In cultivated commercial crop species, genetic diversity tends to decrease because of the extensive breeding processes. Therefore, germplasm of commercial crop species, such as Brassica napus L. should be evaluated and the genotypes, which have higher genetic diversity index, should be addressed as potential parental cross materials in breeding programs. In this study, the genetic diversity was analysed by using randomly amplified polymorphic DNA analysis (RAPD) technique in nine Turkish commercial rapeseed varieties. The RAPD primers (10-mer oligonucleotides) produced 51 scorable loci, 31 loci of which were polymorphic (60.78%) and 20 loci (39.22%) were monomorphic The RAPD bands were scored as binary matrix data and were analysed using POPGENE version 1.32. At locus level, the values of genetic diversity within population (Hs) and total (HT) were 0.15 and 0.19 respectively. The genetic differentiation (GST) and the gene flow (Nm) values between the populations were 0.20 and 2.05 respectively. The mean number of alleles (na), the mean number of effective alleles (nae), and the mean value of genetic diversity (He) were 2.00, 1.26, and 0.19 respectively. According to Pearson’s correlation, multiple regression and principal component analyses, eco-geographical conditions in combination had significant effect on genetic indices of commercial B. napus L. varieties were discussed.


Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 543
Author(s):  
Shijing Feng ◽  
Jinshuang Niu ◽  
Zhenshan Liu ◽  
Lu Tian ◽  
Xiangyuan Wang ◽  
...  

Chinese pepper, referring to Zanthoxylum bungeanum Maxim. and Zanthoxylum armatum DC. species, is an important spice crop that has long attracted people’s interest due to its extensive application in Asian cuisine to improve taste. Numerous cultivars have been developed during the long history of domestication and cultivation. However, little to no information is available on the genetic diversity and evolutionary relationships of Chinese pepper cultivars and their historical diversification has not been clarified. Herein, we sequenced two nrDNA non-coding region markers, the external transcribed spacer (ETS) and the internal transcribed spacer 2 (ITS2), to assess genetic diversity and phylogenetic relationships among 39 cultivated and wild populations of Chinese pepper from eight provinces and to address the question of ancient demographic trends which were probably influenced by changing climate during evolutionary history. In total, 31 haplotypes were identified based on 101 polymorphism sites. Our results revealed relatively high level of genetic variation despite long-term cultivation of this crop. AMOVA revealed that genetic variation existed predominantly within provinces rather than among provinces. The genetic structure result based on haplotype network analysis largely reflected historical records, which suggested a Gansu origin for Chinese pepper and an ancient west-to-east spread of Chinese pepper circulating in China. We also provided evidence that changing Pleistocene climates had shaped the demographic trends of Chinese pepper. Taken together, our findings not only suggest that Chinese pepper is a dynamic genetic system that responds to evolutionary forces, but it also provides a fundamental genetic profile for the conservation and responsible exploitation of the extant germplasm of Chinese pepper and for improving the genetic basis for breeding the cultivars.


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