scholarly journals Pathogenomic analyses of Puccinia striiformis f. sp. tritici supports a close genetic relationship between South and East Africa

2021 ◽  
Author(s):  
Hester J. Schalkwyk ◽  
Thomas Adams ◽  
Antoine Persoons ◽  
Willem H. P. Boshoff ◽  
Ruth Wanyera ◽  
...  
2021 ◽  
Vol 17 (4) ◽  
Author(s):  
Joukje Buiteveld ◽  
Herma JJ Koehorst-van Putten ◽  
Linda Kodde ◽  
Ivo Laros ◽  
Giorgio Tumino ◽  
...  

AbstractThe Netherlands’ field genebank collection of European wild apple (Malus sylvestris), consisting of 115 accessions, was studied in order to determine whether duplicates and mistakes had been introduced, and to develop a strategy to optimize the planting design of the collection as a seed orchard. We used the apple 20K Infinium single nucleotide polymorphism (SNP) array, developed in M. domestica, for the first time for genotyping in M. sylvestris. We could readily detect the clonal copies and unexpected duplicates. Thirty-two M. sylvestris accessions (29%) showed a close genetic relationship (parent-child, full-sib, or half-sib) to another accession, which reflects the small effective population size of the in situ populations. Traces of introgression from M. domestica were only found in 7 individuals. This indicates that pollination preferentially took place among the M. sylvestris trees. We conclude that the collection can be considered as mainly pure M. sylvestris accessions. The results imply that it should be managed as one unit when used for seed production. A bias in allele frequencies in the seeds may be prevented by not harvesting all accessions with a close genetic relationship to the others in the seed orchard. We discuss the value of using the SNP array to elaborate the M. sylvestris genetic resources more in depth, including for phasing the markers in a subset of the accessions, as a first step towards genetic resources management at the level of haplotypes.


Author(s):  
Suparat Srithawong ◽  
Kanha Muisuk ◽  
Metawee Srikummool ◽  
Jatupol Kampuansai ◽  
Pittayawat Pittayaporn ◽  
...  

BMC Genomics ◽  
2020 ◽  
Vol 21 (S7) ◽  
Author(s):  
José R. Sandoval ◽  
Daniela R. Lacerda ◽  
Marilza M. S. Jota ◽  
Paulo Robles-Ruiz ◽  
Pierina Danos ◽  
...  

Abstract Background According to history, in the pre-Hispanic period, during the conquest and Inka expansion in Ecuador, many Andean families of the Cañar region would have been displaced to several places of Tawantinsuyu, including Kañaris, a Quechua-speaking community located at the highlands of the Province of Ferreñafe, Lambayeque (Peru). Other families were probably taken from the Central Andes to a place close to Kañaris, named Inkawasi. Evidence of this migration comes from the presence near the Kañaris–Inkawasi communities of a village, a former Inka camp, which persists until the present day. This scenario could explain these toponyms, but it is still controversial. To clarify this historical question, the study presented here focused on the inference of the genetic relationship between ‘Cañaris’ populations, particularly of Cañar and Ferreñafe, compared to other highland populations. We analysed native patrilineal Y chromosome haplotypes composed of 15 short tandem repeats, a set of SNPs, and maternal mitochondrial DNA haplotypes of control region sequences. Results After the genetic comparisons of local populations—three from Ecuador and seven from Peru—, Y chromosome analyses (n = 376) indicated that individuals from the Cañar region do not share Y haplotypes with the Kañaris, or even with those of the Inkawasi. However, some Y haplotypes of Ecuadorian ‘Cañaris’ were associated with haplotypes of the Peruvian populations of Cajamarca, Chivay (Arequipa), Cusco and Lake Titicaca, an observation that is congruent with colonial records. Within the Kañaris and Inkawasi communities there are at least five clans in which several individuals share haplotypes, indicating that they have recent common ancestors. Despite their relative isolation, most individuals of both communities are related to those of the Cajamarca and Chachapoyas in Peru, consistent with the spoken Quechua and their geographic proximity. With respect to mitochondrial DNA haplotypes (n = 379), with the exception of a shared haplotype of the D1 lineage between the Cañar and Kañaris, there are no genetic affinities. Conclusion Although there is no close genetic relationship between the Peruvian Kañaris (including Inkawasi) and Ecuadorian Cañar populations, our results showed some congruence with historical records.


1989 ◽  
Vol 44 (10) ◽  
pp. 891-923 ◽  
Author(s):  
A. E. Ringwood

Abstract The early thermal state of the Earth provides important constraints on hypotheses relating to its origin and its connection with the Moon. The currently popular giant impact hypothesis of lunar origin requires the Earth’s mantle to have been completely melted during the impact. Differentiation of a molten mantle would have produced strong chemical and mineralogical stratification, causing the mantle to become gravitationally stable and resistant to convective rehomogenization. The resulting composition and mineralogy of the upper mantle and primitive crust would have been dramatically different from those which have existed during the past 3.8 b. y. It is concluded that the Earth’s mantle was not extensively melted at the conclusion of accretion of the planet and therefore the hypothesis that the Moon was formed by the impact of a martian-sized planetesimal on the proto-Earth is probably incorrect. Nevertheless, a wide range of geochemical evidence demonstrates the existence of a close genetic relationship between the Moon and the Earth’s mantle. The key evidence relates to the processes of core formation in planetary bodies and resultant abundance patterns of siderophile elements which remain in their silicate mantles. Because of the complexity of the core formation process within a given body and the multiplicity of chemical and physical processes involved, the mantle siderophile signature is expected to be a unique characteristic. Thus, the siderophile signatures of Mars and of the eucrite parent body are quite distinct from that of the Earth’s mantle. Lunar siderophile geochemistry is reviewed in detail. It is demonstrated that a large group of siderophile elements display similar abundances in the terrestrial and lunar mantles. The similarity implies that a major proportion of the material now in the Moon was derived from the Earth’s mantle after core formation. This implication, however, does not require that the bulk compositions of the lunar and terrestrial mantles should be essentially identical, as is often assumed. Factors which may contribute to significant compositional differences between the two bodies within the context of a close genetic relationship are reviewed. The most promising mechanism for removing terrestrial material from the Earth’s mantle arises from the impacts of a number of large (0.001 to 0.01 ME) but not giant (≥ 0.1 ME) planetesimals after core formation and at the terminal stage of the Earth’s accretion. These impacts evaporated several times their own masses of mantle material and shock-melted considerably more. However, they did not lead to complete or extensive (e.g. > 50%) melting of the entire mantle. Impact-generated clouds of shock-melted spray and vapours were accelerated to high velocities in the presence of a primitive terrestrial atmosphere that co-rotated with the Earth. This provided an effective means of transferring angular momentum from the Earth to the ejected material which condensed to form a ring of Earth-orbiting planetesimals and moonlets. The Moon was formed by coagulation from material derived from the outer regions of this ring. Accretion of the Earth in the presence of the gases of the solar nebula and the co-rotating primitive terrestrial atmosphere may also have provided a mechanism for generating the rapid prograde spin of the proto-Earth.


1992 ◽  
Vol 70 (9) ◽  
pp. 1758-1764 ◽  
Author(s):  
Nils Hallenberg ◽  
Ellen Larsson

Mating tests were performed to analyze the genetic relationship between two intersterile sibling species in Peniophora cinerea (Fr.) Cooke in Europe. Two newly collected specimens from North Europe were found to be compatible with both sibling species, which strongly suggests a close genetic relationship and a sterility barrier of simple genetic origin. The two sibling species, which differ in their substrate selectivity, are accepted as subspecies. One subspecies is restricted to decorticated wood of Fagus, and occasionally the fruit bodies are associated with insect galls. Intersterility was also found in some combinations with two other specimens from Canada and Turkey, but no linkage was found with a particular substrate. Specimens from Taiwan were found to be partially compatible with specimens from Europe, Turkey, and Canada. Distinct differences between the subspecies were found in banding patterns from isoelectric focusing of buffer-soluble mycelial proteins. It is proposed that the kind of intersterility found here is intraspecific and should be looked upon as part of a propagation strategy. Key words: speciation, evolution, Basidiomycetes, isoelectric focusing, insect gall, mating test.


2016 ◽  
Vol 15 (4) ◽  
pp. 862-871
Author(s):  
Ji-long HAN ◽  
Min YANG ◽  
Ting-ting GUO ◽  
Jian-bin LIU ◽  
Chun-e NIU ◽  
...  

Author(s):  
Blake M. Hanson ◽  
An Q. Dinh ◽  
Truc T. Tran ◽  
Sebastian Arenas ◽  
Darryl Pronty ◽  
...  

Clinical cases of C. auris noted during a COVID-19 surge led to an epidemiological, clinical, and genomic investigation. Evaluation identified a close genetic relationship but no conclusive epidemiologic link between all cases. Prolonged hospitalization due to critical illness from COVID-19 and use of antimicrobials may have contributed to clinical infections.


2000 ◽  
Vol 182 (22) ◽  
pp. 6322-6330 ◽  
Author(s):  
Timothy P. Stinear ◽  
Grant A. Jenkin ◽  
Paul D. R. Johnson ◽  
John K. Davies

ABSTRACT Previous studies of the 16S rRNA genes from Mycobacterium ulcerans and Mycobacterium marinum have suggested a very close genetic relationship between these species (99.6% identity). However, these organisms are phenotypically distinct and cause diseases with very different pathologies. To investigate this apparent paradox, we compared 3,306 nucleotides from the partial sequences of eight housekeeping and structural genes derived from 18M. ulcerans strains and 22 M. marinumstrains. This analysis confirmed the close genetic relationship inferred from the 16S rRNA data, with nucleotide sequence identity ranging from 98.1 to 99.7%. The multilocus sequence analysis also confirmed previous genotype studies of M. ulceransthat have identified distinct genotypes within a geographical region. Single isolates of both M. ulcerans and M. marinum that were shown by the sequence analysis to be the most closely related were then selected for further study. One- and two-dimensional pulsed-field gel electrophoresis was employed to compare the architecture and size of the genome from each species. Genome sizes of approximately 4.4 and 4.6 Mb were obtained forM. ulcerans and M. marinum, respectively. Significant macrorestriction fragment polymorphism was observed between the species. However, hybridization analysis of DNA cleaved with more frequently cutting enzymes identified significant preservation of the flanking sequence at seven of the eight loci sequenced. The exception was the 16S rRNA locus. Two high-copy-number insertion sequences, IS2404 and IS2606, have recently been reported in M. ulcerans, and significantly, these elements are not present in M. marinum. Hybridization of theAseI restriction fragments from M. ulcerans with IS2404 and IS2606 indicated widespread genome distribution for both of these repeated sequences. Taken together, these data strongly suggest that M. ulcerans has recently diverged from M. marinumby the acquisition and concomitant loss of DNA in a manner analogous to the emergence of M. tuberculosis, where species diversity is being driven mainly by the activity of mobile DNA elements.


1998 ◽  
Vol 88 (3) ◽  
pp. 247-255 ◽  
Author(s):  
M. Charalambous ◽  
M. Arzube ◽  
S. Lowell

AbstractTwo new cytotypes of the onchocerciasis vector blackfly Simulium exiguum Roubaud are described from amazonian Ecuador. As transmission of the disease does not occur in the region, the two cytotypes are not currently vectors, The Napo form (N = 113) differs cytologically from the chromosomal standard of the species, the Cayapa form, through possession of the fixed paracentric inversions IL-E and IIIL-L; the Huatarac form (N = 22) differs by the fixed inversions IL-L and IIIL-D + L. Both forms form a subcomplex, termed the ‘amazonian’ subcomplex, through sharing the fixed inversion IIIL-L. They also share a number of polymorphic inversions, but neither form possesses sex-linked inversions. The fixed and sex-linked inversions of the previously described Aguarico form were found to be polymorphic and autosomal in the Napo and Huatarac forms, suggesting a close genetic relationship among these forms. The Napo form is distributed throughout the Napo river system (except in the Rio Huatarac) and found in the Rio Aguarico, whereas the Huatarac form is unique to the Rio Huatarac. As their distributions in this study were allopatric, the species status of the two cytotypes could not be tested. The Aguarico form was not found in the Rio Aguarico, nor in any of the other rivers sampled. Whether the Napo form has replaced the Aguarico form in the Rio Aguarico, or whether its absence is due to seasonal variation requires further investigation.


1968 ◽  
Vol 46 (11) ◽  
pp. 1423-1429 ◽  
Author(s):  
Alexander Olchowecki ◽  
Harold J. Brodie

A recently described bird's nest fungus, Cyathus helenae Brodie, was grown in pure culture. Monosporous mycelia developed irregularly pigmented areas of a dark umber color and most displayed a marked tendency to produce a variety of saltant types. Saltants differed from parental mycelia in growth rate, pigmentation, and the amount of aerial mycelium developed. When mated, monosporous mycelia behaved according to a tetrapolar pattern. Mating-type genes were identical in mycelia originating from fruit bodies of widely separated areas. All mycelia of C. helenae were very different in pigment and texture from mycelia of C. striatus (Huds.) Willd. ex Pers. Dikaryotic mycelia were developed in certain matings of monosporous mycelia of C. helenae with monosporous mycelia of C. striatus, but this close genetic relationship is not taken as indicative of conspecificity.


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