scholarly journals Automictic parthenogenesis in the parasitoid Venturia canescens (Hymenoptera: Ichneumonidae) revisited

Genome ◽  
2000 ◽  
Vol 43 (6) ◽  
pp. 939-944 ◽  
Author(s):  
Leo W Beukeboom ◽  
Laas P Pijnacker
Keyword(s):  
Genetic Variation ◽  
Pcr Amplification ◽  
Parasitoid Wasp ◽  
Reduction Division ◽  
Exact Nature ◽  
Normal Pattern ◽  
Venturia Canescens ◽  
Central Fusion ◽  
Cytological Mechanism

Both arrhenotokous and thelytokous reproduction are known to occur in the parasitoid wasp Venturia canescens. The cytological mechanism of thelytoky was previously reported to involve the formation of a restitution metaphase after the reduction division, but the exact nature of the subsequent divisions, whether reductional or equational, remained unclear. We reinvestigated the cytological mechanisms in a thelytokous strain collected in France. Our observations confirm previous results, but an equational and not a reduction division was observed after restitution. This type of reproduction can be classified as central fusion automictic parthenogenesis. In two arrhenotokous strains the normal pattern of oogenesis and syngamy of Hymenoptera was observed. In addition, we used PCR amplification to show that thelytoky in V. canescens is not caused by Wolbachia bacteria. The results are discussed in relation to maintenance of heterozygosity and female sex.Key words: automictic parthenogenesis, central fusion, genetic variation, restitution, Venturia canescens, Wolbachia bacteria.

scholarly journals Population genetic variation analysis of bitter gourd wilt caused by Fusarium oxysporum f. sp. momordicae in China using inter simple sequence repeats (ISSR) molecular markers

2021 ◽  
Author(s):  
Rui Zang ◽  
Ying Zhao ◽  
Kangdi Guo ◽  
Kunqi Hong ◽  
Huijun Xi ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Differentiation ◽  
Fusarium Oxysporum ◽  
Diversity Index ◽  
Gene Diversity ◽  
Pcr Amplification ◽  
Bitter Gourd ◽  
Diseased Plant ◽  
Variation Analysis ◽  
Group I

AbstractBitter gourd wilt caused by Fusarium oxysporum f. sp. momordicae (FOM) is a devastating crop disease in China. A total of 173 isolates characteristic of typical Fusarium oxysporum with abundant microconidia and macroconidia on white or ruby colonies were obtained from diseased plant tissues. BLASTn analysis of the rDNA-ITS of the isolates showed 99% identity with F. oxysporum species. Among the tested isolates, three were infectious toward tower gourd and five were pathogenic to bottle gourd. However, all of the isolates were pathogenic to bitter gourd. For genetic differences analysis, 40 ISSR primers were screened and 11 primers were used for ISSR-PCR amplification. In total, 127 loci were detected, of which 76 were polymorphic at a rate of 59.84%. POPGENE analysis showed that Nei’s gene diversity index (H) and Shannon’s information index (I) were 0.09 and 0.15, respectively, which indicated that the genetic diversity of the 173 isolates was low. The coefficient of gene differentiation (Gst = 0.33 > 0.15) indicated that genetic differentiation was mainly among populations. The strength of gene flow (Nm = 1.01 > 1.0) was weak, indicating that the population differentiation caused by gene drift was blocked to some degree. The dendrogram based on ISSR markers showed that the nine geographical populations were clustered into two groups at the threshold of genetic similarity coefficient of 0.96. The Shandong and Henan populations were clustered into Group I, while the Guangdong, Hainan, Guangxi, Fujian, Jiangxi, and Hubei populations constituted Group II. Results of the genetic variation analysis showed that the Hunan and Guangxi populations had the highest degree of genetic differentiation, while the Hubei population had the lowest genetic differentiation. Our findings enrich the knowledge of the genetic variation characteristics of FOM populations with the goal of developing effective disease-management programs and resistance breeding programs.

scholarly journals Branching Pattern in Successive Generations of Peanuts Arachis hypogaea L.

1980 ◽  
Vol 7 (1) ◽  
pp. 41-45
Author(s):  
C. Harkness ◽  
D. J. Wright
Keyword(s):  
Genetic Variation ◽  
Environmental Effect ◽  
Genotype By Environment Interaction ◽  
Environment Interaction ◽  
Branching Pattern ◽  
Normal Pattern ◽  
Genotype By Environment ◽  
Arachis Hypogaea L ◽  
Branching Patterns ◽  
Successive Generations

Abstract Variation in branching pattern was studied in six Virginia group peanut cultivais (ssp. hypogaea var. hypogaea). Lines with genetically distinct branching patterns differing from the normal pattern were readily found in two of the cultivars. These variable lines showed no yield advantage over the normal lines. It was concluded that there is considerable genetic variation for branching pattern in Virginia peanuts. The variation could be ascribed to a range of modifier genes which can change the normal pattern of branching. There were indications of a strong environmental effect on branching pattern and of a genotype by environment interaction.

Genetic variation in populations of two Mediterranean annual pasture legumes (Biserrula pelecinus L. and Ornithopus compressus L.) and associated rhizobia

1999 ◽  
Vol 50 (3) ◽  
pp. 303 ◽  
Author(s):  
A. Loi ◽  
J. G. Howieson ◽  
P. S. Cocks ◽  
S. J. Carr
Keyword(s):  
Genetic Variation ◽  
Flowering Time ◽  
Morphological Traits ◽  
Root Nodule ◽  
Dna Analysis ◽  
Phenotypic Variability ◽  
Pcr Amplification ◽  
Nodule Bacteria ◽  
Pasture Legumes ◽  
Ornithopus Compressus

Genetic variation between and within populations of Biserrula pelecinus L. (biserrula) and Ornithopus compressus L. (yellow serradella) and associated rhizobia was studied using germplasm collected from sites in central-eastern and south-eastern Sardinia (Italy). Pods and root-nodule bacteria were collected on diagonal transects at each site. Plants were characterised in nursery rows and the rhizobia were isolated and tested for their effectiveness. Thirteen morphological traits were recorded and the results were analysed using cluster analysis. Genetic and phenotypic variation of rhizobia were assessed using DNA analysis (PCR, RAPDs) and effectiveness indices, respectively. Genetic variation based on morphological traits was found between and within sites for both species. Pod characteristics and flowering time were the most important traits assisting in discriminating between accessions. Flowering time varied more in serradella than in biserrula, particularly at Cantoniera Cannas. Although all rhizobial strains nodulated all accessions of biserrula, great variability in capacity to fix nitrogen was evident between and within sites. Distinct PCR amplification profiles were generated for individual rhizobial strains, which confirmed the phenotypic variability (effectiveness indices) of the strains. No relationship was found between host and rhizobia variation. The results are discussed in terms of (a) genetic differences for each species within and between sites; (b) differences in behaviour in respect to genetic variation between biserrula, serradella, and other Mediterranean annual legumes; and (c) spatial variability and symbiotic effectiveness of rhizobia.

Genetic variation of microsatellite and mitochondrial DNA markers in broad whitefish (Coregonus nasus) in the Colville and Sagavanirktok rivers in northern Alaska

1997 ◽  
Vol 54 (7) ◽  
pp. 1548-1556 ◽  
Author(s):  
J C Patton ◽  
B J Gallaway ◽  
R G Fechhelm ◽  
M A Cronin
Keyword(s):  
Mitochondrial Dna ◽  
Genetic Variation ◽  
Gene Flow ◽  
Microsatellite Loci ◽  
Genetic Relationships ◽  
Nuclear Genome ◽  
Pcr Amplification ◽  
Colville River ◽  
Limited Gene Flow ◽  
Northern Alaska

There has been concern that a causeway leading to oil production facilities in the Alaskan Beaufort Sea could affect the extent of emigration from, and immigration into, a population of broad whitefish (Coregonus nasus) in the Sagavanirktok River. To assess this, we analyzed the genetic relationships of the broad whitefish populations in the Sagavanirktok River, and the nearest adjacent population, in the Colville River. Three microsatellite loci from the nuclear genome, and the NADH-1 gene of mitochondrial DNA (mtDNA), were analyzed. Diploid genotypes were determined with PCR amplification of the microsatellite loci, and mtDNA genotypes were identified with PCR amplification followed by sequencing of 798 nucleotides. Several alleles were identified at each locus and both populations had high levels of genetic variation. There is significant differentiation of the Sagavanirktok River and Colville River broad whitefish stocks for the three microsatellite loci (FST = 0.031) but not mtDNA (FST < 0.001). Possible explanations for the lower level of differentiation of mtDNA than microsatellites include female-mediated gene flow between populations, skewed sex ratios, natural selection, or mutation. The results indicate that there is limited gene flow between the Colville and Sagavanirktok rivers, which represent semi-isolated spawning populations.

scholarly journals Chromosome linkage in oenothera, with special reference to some F 1 hybrids

1929 ◽  
Vol 105 (736) ◽  
pp. 207-230 ◽  
Keyword(s):  
Embryo Sac ◽  
Reduction Division ◽  
Exact Nature ◽  
Chromosome Behaviour ◽  
Final Solution ◽  
Female Side ◽  
Chromosome Configuration ◽  
Pure Lines ◽  
Mother Cells ◽  
Derivatives Of

Oenothera has placed a large part in our initiation into many new fields of cytological and genetical research. Since ring-formation of chromosomes was first observed in this genus by Cleland a few years ago, it has become apparent as a characteristic of meiosis in several other Angiosperms, but whether these are entirely comparable to Oenothera is at present doubtful. It is to Oenothera that we look for the final solution of many of the difficulties encountered in any endeavour to correlate these phenomena with chromosome behaviour in more typical genera, for within the Onagra group are numerous inter-fertile species, each of which is characterised by its own particular chromosome configuration, which is constant throughout all the pollen mother-cells. Such rings are now known to occur also at reduction division in the embryo-sac mother-cell of a number of forms, and it has been found that similar configurations prevail on the male and female side in any particular species. This is observed by the author to be the ease in Oe. rubricalyx (unpublished) and similar conditions have been described by Håbansson (1928) in several other derivatives of Oe. Lamarckiana . It seemed that a systematic study of the linkage of the chromosomes in a number of pure lines and in the hybrids between them was desirable, in that it might throw some light on the exact nature of pairing and chromosome linkage. Some such hybrids have already been described by Cleland (1927). This paper will deal with the chromosome behaviour in a number of F 1 hybrids between pure lines in which the meiotic divisions have already been studied (Sheffield, 1927).

scholarly journals A Short Tandem Repeat Assay for Studying Genetic Variation in Madurella mycetomatis (MmySTR)

2020 ◽  
Author(s):  
Bertrand Nyuykonge ◽  
Kimberly Eadie ◽  
Willemien H. A. Zandijk ◽  
Sarah A. Ahmed ◽  
Marie Desnos-Ollivier ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Tandem Repeats ◽  
Diversity Index ◽  
Clinical Manifestations ◽  
Pcr Amplification ◽  
Reference Database ◽  
Madurella Mycetomatis ◽  
Typing Technique ◽  
Short Tandem ◽  
D Value

Introduction: Madurella mycetomatis is the major causative agent of eumycetoma, a neglected tropical infection characterized by painless subcutaneous lesions, inflammation and grains draining from multiple sinuses. To study the epidemiology of mycetoma, a robust discriminatory typing technique is needed. We describe the use of a Short Tandem Repeats assay (MmySTR) for genotyping of M. mycetomatis isolates predominantly from Sudan. Methods: Eleven microsatellite markers (3 dinucleotides, 4 trinucleotide repeats and 4 tetranucleotide repeats) were selected from the M. mycetomatis MM55 genome using the Tandem Repeats Finder software. PCR amplification primers were designed for each microsatellite marker using primer3 software and amplified in a multicolor multiplex PCR approach. To establish the extent of genetic variation within the population, a collection of 120 clinical isolates from different regions was genotyped with this assay. Results: The 11 selected MmySTR markers showed a large genotypic heterogeneity. From a collection of 120 isolates, 108 different genotypes were obtained. The Simpsons’ diversity index (D) value for individual markers ranged from 0.081-0.881, the combined panel displayed an overall D value of 0.997. The MmySTR assay demonstrated high stability, reproducibility and specificity. Conclusion: The MmySTR assay is a promising new typing technique that can be used to genotype isolates of M. mycetomatis. Apart from the possible contribution of host factors, the genetic diversity observed among this group of isolates might contribute to the different clinical manifestations of mycetoma. We recommend the MmySTR assay to be used to establish a global reference database for future study of M. mycetomatis isolates.

scholarly journals Variasi Genetik dalam Populasi Kultivar Kopi Arabika Berbuah Kuning di Lahan Petani Berdasarkan Penanda SSRs

2016 ◽  
Vol 3 (2) ◽  
pp. 83
Author(s):  
Dani Dani ◽  
Nur Kholilatul Izzah ◽  
Enny Randriani
Keyword(s):  
Genetic Variation ◽  
Environmental Conditions ◽  
Genetic Similarity ◽  
Binary Data ◽  
Genetic Relationships ◽  
Pcr Amplification ◽  
Morphological Characters ◽  
Polymorphic Band ◽  
Group Method ◽  
Arabica Coffee

<p><em>Identification of the genetic diversity within populations of yellow-berried Arabica coffee cultivar based on morphological characters faced an obstacle in finding identical environmental conditions at farmers field. Therefore, an approach which is not influenced by differences in environmental conditions is required, for instance based on DNA polymorphism. The research aimed to analyze genetic variation within populations of yellow-berried Arabica coffee cultivar based on SSRs markers. The research was conducted in the Integrated Laboratory, Indonesian Industrial and Beverage Crops Research Institute, Sukabumi, from April until June 2015. The leaf samples for DNA extraction were obtained from yellow-berried Arabica coffee cultivar (AGK-1) and two red-berried cultivars  as controls, namely  ABP-1 (dwarf type) and Typica (tall type). AGK-1 and ABP-1 cultivars consisted of 17 and 5 individual numbers, respectively, whereas Typica cultivar comprised three individuals. PCR amplification was carried out using 12 SSR primers. Four primers (M24, SSRCa052, M32, and M42) produced polymorphic band. The binary data obtained in this research was subsequently processed using NTSYS-PC program version 2.1. The genotypes were grouped  based on a genetic similarity matrix using the unweighted pair group method arithmetic mean (UPGMA). The result showed the existence of genetic variation among individual of AGK-1 cultivars, which forming three clusters at the genetic similarity value of 67%. One cluster exhibited close genetic relationships between some individuals within the population of AGK-1 cultivar and Typica cultivar. Meanwhile, the other two clusters showed high genetic similarity between AGK-1 cultivar and ABP-1 cultivar. The result demonstrated the possibility of gene flow between genotypes or residual heterozygosity within the population of  AGK-1 cultivar at farmers field, which required a further study.</em><em></em></p>

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