Genetic Diversity of Gibberella Fujikuroi Isolates from Different Geographic Origins

1997 ◽  
Vol 25 (3) ◽  
pp. 557-560 ◽  
Author(s):  
Ulrike F. Schlacht ◽  
Evelyn M. Möller ◽  
Hartwig G. Geiger
Keyword(s):  
Genetic Diversity ◽  
Gibberella Fujikuroi ◽  
Geographic Origins

Genetic diversity of fringed brome (Bromus ciliatus) as determined by amplified fragment length polymorphism

2005 ◽  
Vol 83 (10) ◽  
pp. 1322-1328 ◽  
Author(s):  
Yong-Bi Fu ◽  
Bruce E. Coulman ◽  
Yasas S.N. Ferdinandez ◽  
Jacques Cayouette ◽  
Paul M. Peterson
Keyword(s):  
Genetic Diversity ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Habitat Restoration ◽  
Fragment Length Polymorphism ◽  
Natural Populations ◽  
Germplasm Conservation ◽  
Amplified Fragment Length Polymorphism ◽  
Large Area ◽  
Geographic Origins

Fringed brome ( Bromus ciliatus L.) is found in native stands throughout a large area of North America. Little is known about the genetic diversity of this species. The amplified fragment length polymorphism (AFLP) technique was applied to assess the genetic diversity of 16 fringed brome populations sampled in Canada from the provinces of Alberta, British Columbia, Quebec, and Saskatchewan. Four AFLP primer pairs were employed to screen 82 samples with four to six samples per population and 83 polymorphic AFLP bands scored for each sample. The frequencies of the scored bands in all assayed samples ranged from 0.01 to 0.99 and averaged 0.53. Analysis of molecular variance revealed that 52.6% of the total AFLP variation resided among the 16 populations and 20.6% among the four provinces. The five Quebec populations appeared to be genetically the most diverse and distinct. The AFLP variability observed was significantly associated with the geographic origins of the fringed brome populations. These findings are useful for sampling fringed brome germplasm from natural populations for germplasm conservation and should facilitate the development of genetically diverse regional cultivars for habitat restoration and revegetation.

scholarly journals Human migration and the spread of malaria parasites to the New World

2017 ◽  
Author(s):  
Priscila T. Rodrigues ◽  
Hugo O. Valdivia ◽  
Thais C. de Oliveira ◽  
João Marcelo P. Alves ◽  
Ana Maria R. C. Duarte ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Plasmodium Falciparum ◽  
Gene Flow ◽  
Atlantic Forest ◽  
Amazon Basin ◽  
New World ◽  
Human Migration ◽  
Malaria Parasites ◽  
Mitochondrial Haplotypes ◽  
Geographic Origins

AbstractBackgroundThe Americas were the last continent to be settled by modern humans, but how and when human malaria parasites arrived in the New World is uncertain. Here, we apply phylogenetic analysis and coalescent-based gene flow modeling to a global collection of Plasmodium falciparum and P. vivax mitogenomes to infer the demographic history and geographic origins of malaria parasites circulating in the Americas. Importantly, we examine P. vivax mitogenomes from previously unsampled forest-covered sites along the Atlantic Coast of Brazil, including the vivax-like species P. simium that locally infects platyrrhini monkeys.ResultsThe best-supported gene flow models are consistent with migration of both malaria parasites from Africa and South Asia to the New World, with no genetic signature of a population bottleneck upon parasite's arrival in the Americas. We found evidence of additional gene flow from Melanesia in P. vivax (but not P. falciparum) mitogenomes from the Americas and speculate that some P. vivax lineages might have arrived with the Australasian peoples who contributed genes to Native Americans in pre-Columbian times. Mitochondrial haplotypes characterized in P. simium from monkeys from the Atlantic Forest are shared by local humans. These vivax-like lineages have not spread to the Amazon Basin, are much less diverse than P. vivax circulating elsewhere in Brazil, and show no close genetic relatedness with P. vivax populations from other continents.ConclusionsEnslaved peoples brought from a wide variety of African locations were major carriers of P. falciparum mitochondrial lineages into the Americas, but additional human migration waves are likely to have contributed to the extensive genetic diversity of present-day New World populations of P. vivax. The reduced genetic diversity of vivax-like monkey parasites, compared with human P. vivax from across this country, argues for a recent human-to-monkey transfer of these lineages in the Atlantic Forest of Brazil.Author summaryMalaria is currently endemic to the Americas, with over 400,000 laboratory-confirmed infections reported annually, but how and when human malaria parasites entered this continent remains largely unknown. To determine the geographic origins of malaria parasites currently circulating in the Americas, we examined a global collection of Plasmodium falciparum and P. vivax mitochondrial genomes, including those from understudied isolates of P. vivax and P. simium, a vivax-like species that infect platyrrhini monkeys, from the Atlantic Forest of Brazil. We found evidence of significant historical migration to the New World of malaria parasites from Africa and, to a lesser extent, South Asia, with further genetic contribution of Melanesian lineages to South American P. vivax populations. Importantly, mitochondrial haplotypes of P. simium are shared by monkeys and humans from the Atlantic Forest, most likely as a result of a recent human-to-monkey transfer. Interestingly, these potentially zoonotic lineages are not found in the Amazon Basin, the main malaria-endemic area in the Americas. We conclude that enslaved Africans were the main carriers of P. falciparum mitochondrial lineages into the Americas, whereas additional migration waves of Australasian peoples and parasites may have contributed to the genetic makeup of present-day New World populations of P. vivax.

DNA-Based Marker Systems to Determine Genetic Diversity of Weedy Species and Their Application to Biocontrol

Weed Science ◽  
1995 ◽  
Vol 43 (3) ◽  
pp. 504-513 ◽  
Author(s):  
Scott J. Nissen ◽  
Robert A. Masters ◽  
Donald J. Lee ◽  
Martha L. Rowe
Keyword(s):  
Genetic Diversity ◽  
Biological Control ◽  
Weed Control ◽  
Random Amplified Polymorphic Dna ◽  
Biological Weed Control ◽  
Multiple Introductions ◽  
Introduced Populations ◽  
Length Polymorphisms ◽  
Geographic Origins ◽  
Weedy Species

DNA-based molecular markers may provide information about introduced weedy species that would be useful in biological weed control efforts. Chloroplast DNA restriction fragment length polymorphisms (cpDNA RFLP) and random amplified polymorphic DNA (RAPD) analysis are two DNA-based marker techniques that can provide estimates of genetic variation in native and introduced populations of weedy species. Profiles provided by these techniques could furnish the necessary information to determine the geographic origins of introduced species and provide evidence for multiple introductions. Although DNA-based markers would not necessarily identify the genetic basis for host-pest compatibility, they would enable identification of specific host genotypes. Current criteria for selecting a weedy species as a target for biological control are primarily political and economic. The importance of genetic diversity and population structure in determining the vulnerability of plant populations to insects or diseases has not been fully appreciated. Estimates of genetic diversity based on DNA marker analysis could be used as one criteria for determining which plants are targeted for biological control. The success of biological weed control efforts has been limited by the high levels of genetic diversity occurring in target weed specks and the lack of biocontrol agent and target weed compatibilities. DNA-based markers may be used to increase our understanding of these factors and contribute to the success of biological weed control by helping to target the most vulnerable species and provide more realistic expectations of the potential for success given available resources.

scholarly journals Genetic Diversity among Clostridium botulinum Strains Harboringbont/A2andbont/A3Genes

2012 ◽  
Vol 78 (24) ◽  
pp. 8712-8718 ◽  
Author(s):  
Carolina Lúquez ◽  
Brian H. Raphael ◽  
Lavin A. Joseph ◽  
Sarah R. Meno ◽  
Rafael A. Fernández ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Clostridium Botulinum ◽  
Type A ◽  
Gene Clusters ◽  
Nucleotide Sequencing ◽  
Toxin Gene ◽  
Content Type ◽  
Geographic Origins ◽  
Diversity Studies ◽  
Insight Into

ABSTRACTClostridium botulinumtype A strains are known to be genetically diverse and widespread throughout the world. Genetic diversity studies have focused mainly on strains harboring one type A botulinum toxin gene,bont/A1, although all reportedbont/Agene variants have been associated with botulism cases. Our study provides insight into the genetic diversity ofC. botulinumtype A strains, which containbont/A2(n= 42) andbont/A3(n= 4) genes, isolated from diverse samples and geographic origins. Genetic diversity was assessed by usingbontnucleotide sequencing, content analysis of thebontgene clusters, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). Sequences ofbontgenes obtained in this study showed 99.9 to 100% identity with otherbont/A2orbont/A3gene sequences available in public databases. The neurotoxin gene clusters of the subtype A2 and A3 strains analyzed in this study were similar in gene content.C. botulinumstrains harboringbont/A2andbont/A3genes were divided into six and two MLST profiles, respectively. Four groups of strains shared a similarity of at least 95% by PFGE; the largest group included 21 out of 46 strains. The strains analyzed in this study showed relatively limited genetic diversity using either MLST or PFGE.

scholarly journals Wide Distribution and Genetic Diversity of “Candidatus Neoehrlichia mikurensis” in Rodents from China

2012 ◽  
Vol 79 (3) ◽  
pp. 1024-1027 ◽  
Author(s):  
Hao Li ◽  
Jiafu Jiang ◽  
Fang Tang ◽  
Yi Sun ◽  
Zengde Li ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
16S Rrna ◽  
Phylogenetic Analyses ◽  
Wide Distribution ◽  
Rrna Gene ◽  
16S Rrna Gene Sequences ◽  
Content Type ◽  
Candidatus Neoehrlichia Mikurensis ◽  
Geographic Origins ◽  
Neoehrlichia Mikurensis

ABSTRACT“CandidatusNeoehrlichia mikurensis” was detected by PCR in 4.0% (34/841) of the rodents tested in this study. The 34 rodents represented nine species from seven regions of China. Phylogenetic analyses based on the partialgroELand nearly entire 16S rRNA gene sequences of the agent revealed genetic diversity, which was correlated with its geographic origins.

Further investigations of vegetative compatibility within Fusarium oxysporum f.sp. melonis

1990 ◽  
Vol 68 (6) ◽  
pp. 1245-1248 ◽  
Author(s):  
D. J. Jacobson ◽  
T. R. Gordon
Keyword(s):  
Genetic Diversity ◽  
North America ◽  
Fusarium Oxysporum ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Group ◽  
Culture Collections ◽  
Vegetative Compatibility Groups ◽  
The Third ◽  
Geographic Origins ◽  
Compatibility Group

One hundred and nineteen strains of Fusarium oxysporum f.sp. melonis were characterized by virulence and vegetative compatibility. One hundred and seven strains were placed in four previously reported vegetative compatibility groups: 0130, 0131, 0133, and 0134. Four strains were placed in three new vegetative compatibility groups, and the remaining eight strains were vegetatively self-incompatible. Two of the three new vegetative compatibility groups shared similar geographic origins and distribution with two previously reported vegetative compatibility groups; the third represented a more isolated infestation. All vegetatively self-incompatible isolates originated from culture collections; none have been recently isolated from nature. These newly characterized strains extend our knowledge of genetic diversity in F. oxysporum f.sp. melonis. All four F. oxysporum f.sp. melonis races exist in more than one vegetative compatibility group. European strains represent four vegetative compatibility groups, one of which is present in North America and another in the Middle East. The significance of this diversity is unknown, as are the phylogenetic relationships among strains in this forma specialis.

scholarly journals Molecular Epidemiology Characteristics of Brucella Abortus Strains in China and Their Relationships With World Lineages

2020 ◽  
Author(s):  
Xu-Ming Wang ◽  
Zhongzhi Zhao ◽  
Miao Wang ◽  
Buyun Cui ◽  
Zhiguo Liu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Molecular Epidemiology ◽  
Brucella Abortus ◽  
Variable Number Tandem Repeat ◽  
Northern China ◽  
Variable Number ◽  
Snp Analysis ◽  
High Genetic Diversity ◽  
Geographic Origins ◽  
Epidemic Area

Abstract Background Brucella abortus is a facultative intracellular Gram-negative bacterium that causes chronic persistent infections in humans and livestock. In this study, conventional bio-typing, multiple-locus variable-number tandem repeat analysis (MLVA), and whole-genome sequencing-single-nucleotide polymorphism (WGS-SNP) were used to investigate the molecular epidemiology characteristics of Brucella abortus strains in China and their relationships to world lineages. Results A total of 100 strains were collected from 1953 to 2013, suggesting that B. abortus circulated in China in the past five decades. Moreover, most strains were mainly distributed in the Northwest areas, suggest that provinces in the Northwest were a dominant epidemic area of this disease. During this period, seven biovars were found, indicating that B. abortus had a high diversity of biovars and it is also a potential reason for the disease ongoing spread in the Northern provinces. Strains have high genetic diversity, and bruce07 is the most helpful locus for genotyping of this population. Moreover, 17 MLVA-11 genotypes were found; 13 of them are of known genotypes and four are unassigned genotypes, indicating that B. abortus in this study had several geographic origins. Still, strains from unassigned genotypes may originate from China. Many shared MLVA-16 genotypes were observed in strains from the same provinces in Northern China, which confirmed a B. abortus brucellosis outbreak within Northern regions. WGS-SNP analysis showed that eight Chinese strains formed a ladder-like phylogram (C. Ⅶ) with strains from nine countries, including Uganda, Iraq, Russia, Georgia, Spain, Italy, Egypt, Mongolia, and China; suggest that strains were introduced to these countries from a single source. Conclusions Chinese B. abortus strains had high biovars and genetic diversity as well as represent characteristics of multiple geographic origins, and B. abortus strains from several mainly epidemic areas were closely related to strains from Russia and Mongolia; frequent animal (cattle) trade and exchanges may promote this process. We will provide new and valuable information to strengthening surveillance and control of B. abortus brucellosis in China.

scholarly journals Genetic Diversity Among Ophiosphaerella agrostis Strains Causing Dead Spot in Creeping Bentgrass

Plant Disease ◽  
2006 ◽  
Vol 90 (2) ◽  
pp. 146-154 ◽  
Author(s):  
John E. Kaminski ◽  
Peter H. Dernoeden ◽  
Sue Mischke ◽  
Nichole R. O'Neill
Keyword(s):  
Genetic Diversity ◽  
Genetic Similarity ◽  
Creeping Bentgrass ◽  
The United States ◽  
Dna Fingerprint ◽  
Fingerprint Analysis ◽  
Putting Greens ◽  
Geographic Origins ◽  
Colony Color ◽  
Asexual State

Dead spot (Ophiosphaerella agrostis) is a relatively new disease of young creeping bentgrass and hybrid bermudagrass putting greens in the United States. Little is known about the biology or genetic diversity of the pathogen. O. agrostis is unusual in that it produces prodigious numbers of pseudothecia in the field throughout the summer months and has no known asexual state. A total of 77 O. agrostis isolates were collected from 21 different bentgrass putting greens and one hybrid bermudagrass green in 11 states. DNA fingerprint analysis revealed that 78 out of 97 markers were polymorphic (80.4%), providing 57 unique profiles. Genetic variation of O. agrostis was diverse, and isolates separated into three distinct clades with ≥69% similarity. Analysis of molecular variance indicated that the geographic origins of the isolates and the ability to produce pseudothecia were the best indicators for genetic similarity among O. agrostis isolates. Colony color varied among the isolates, but generally was similar for isolates residing within two clades (B and C). Colony color of isolates within clade A appeared to be a mixture of the colony colors exhibited by clades B and C. Isolates examined within each clade generally had varying levels of pseudothecia production and varying colony colors when grown on PDA. Although O. agrostis is a homothallic species, it is unclear if outcrossing among strains occurs.

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