scholarly journals Identification of SARS-CoV-2 recombinant genomes

2020 ◽  
Author(s):  
David VanInsberghe ◽  
Andrew Neish ◽  
Anice C. Lowen ◽  
Katia Koelle
Keyword(s):  
Genetic Diversity ◽  
Analysis Approach ◽  
Window Of Opportunity ◽  
Phenotypic Characteristics ◽  
Viral Recombination ◽  
Clear Case ◽  
Viral Genetic Diversity ◽  
Low Levels

AbstractViral recombination has the potential to bring about viral genotypes with modified phenotypic characteristics, including transmissibility and virulence. Although the capacity for recombination among Betacoronaviruses is well documented, SARS-CoV-2 has only been circulating in humans for approximately 8 months and thus has had a relatively short window of opportunity for the occurrence of recombination. The ability to detect recombination has further been limited by the relatively low levels of genetic diversity in SARS-CoV-2. Despite this, two studies have reported recombinants among SARS-CoV-2 strains. Here we first revisit these findings with a new analysis approach, arguing that neither presents a clear case of within-SARS-CoV-2 recombination. Applying this same approach to available SARS-CoV-2 sequences, we then identify five recombinant genomes. Each of these genomes contain phylogenetic markers of two distinct SARS-CoV-2 clades. Further, the predicted parent clades of these recombinant genomes were, with one exception, documented to be co-circulating in the country of infection in the two weeks prior to the sample being collected. Our results indicate that recombination among SARS-CoV-2 strains is occurring, but is either not widespread or often remains undetectable given current levels of viral genetic diversity. Efforts to monitor the emergence of new recombinant genomes should therefore be sustained.

scholarly journals Reconciling disparate estimates of viral genetic diversity during human influenza infections

2018 ◽  
Author(s):  
Katherine S. Xue ◽  
Jesse D. Bloom
Keyword(s):  
Genetic Diversity ◽  
Hong Kong ◽  
Deep Sequencing ◽  
Large Scale ◽  
Viral Diversity ◽  
Human Influenza ◽  
Sequencing Data ◽  
Viral Genetic Diversity ◽  
Host Genetic ◽  
Low Levels

AbstractDeep sequencing can measure viral genetic diversity within human influenza infections, but published studies disagree in their estimates of how much genetic diversity is typically present. One large-scale deep-sequencing study of human influenza reported high levels of shared viral genetic diversity among infected individuals in Hong Kong, but subsequent studies of other cohorts have reported little shared viral diversity. We re-analyze sequencing data from four studies of within-host genetic diversity encompassing more than 500 acute human influenza infections. We identify an anomaly in the Hong Kong data that provides a technical explanation for these discrepancies: read pairs from this study are often split between different biological samples, indicating that some reads are incorrectly assigned. These technical abnormalities explain the high levels of within-host variation and loose transmission bottlenecks reported by this study. Studies without these anomalies consistently report low levels of genetic diversity in acute human influenza infections.

scholarly journals Quantitative measures of within-host viral genetic diversity

2021 ◽  
Vol 49 ◽  
pp. 157-163
Author(s):  
Lara Fuhrmann ◽  
Kim Philipp Jablonski ◽  
Niko Beerenwinkel
Keyword(s):  
Genetic Diversity ◽  
Viral Genetic Diversity

scholarly journals Genetic diversity of rice stem borer (Chilo suppressalis Walker) from Northern Iran and comparison with other countries

2016 ◽  
Vol 48 (3) ◽  
pp. 360 ◽  
Author(s):  
M. Shayanmehr ◽  
E. Yoosefi-Lafooraki
Keyword(s):  
Genetic Diversity ◽  
Stem Borer ◽  
Chilo Suppressalis ◽  
Mazandaran Province ◽  
Northern Iran ◽  
Low Genetic Diversity ◽  
High Gene ◽  
Major Pest ◽  
Different Populations ◽  
Low Levels

Rice striped stem borer, <em>Chilo suppressalis</em> Walker (Lepidoptera: Crambidae) is considered the major pest of rice in Iran. Because of the serious damage on rice in Northern Iran, the present study was conducted to investigate genetic diversity within populations of <em>C. suppressalis</em>, from Mazandaran using a template of cytochrome oxidase I gene, 750 bps, (<em>COI</em>). Later the haplotypes from Iran were compared with those found in other countries. According to the results of this study, there is very low genetic diversity (two haplotypes) among different populations of this pest in populations of Northern Iran. The genetic similarity and low levels of genetic diversity of these populations suggest that the pest colonization occurred relatively recently and there is high gene flow between these populations of the province. In addition, haplotypes of Mazandaran province are different with those found in other countries. The similarity of Iranian population (Simorgh) with one population from China indicated that China might be the origin of <em>C. suppresalis</em>.

scholarly journals Population genetic structure and variability in Lindera glauca (Lauraceae) indicates low levels of genetic diversity and skewed sex ratios in natural populations in mainland China

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8304 ◽  
Author(s):  
Biao Xiong ◽  
Limei Zhang ◽  
Shubin Dong ◽  
Zhixiang Zhang
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Isolation By Distance ◽  
Sex Ratios ◽  
Mainland China ◽  
Small Sample ◽  
Chloroplast Microsatellites ◽  
Wild Populations ◽  
Haplotype Networks ◽  
Low Levels

Lindera glauca (Lauraceae) is a tree of economic and ecological significance that reproduces sexually and asexually via apomictic seeds. It is widely distributed in the low-altitude montane forests of East Asia. Despite the potential implications of a mixed reproductive system in terms of genetic diversity, few studies have focused on this aspect. In this study, the genetic structure of wild populations of L. glauca was investigated via genetic analyses. Overall, 13 nuclear microsatellites (nSSRs) and five chloroplast microsatellites (cpSSRs) were used to genotype 300 individual plants, taken from 20 wild populations (a small sample size in some wild populations is due to the limitation of its specific reproduction, leading to certain limitations in the results of this study) and two cultivated populations ranging across nearly the entire natural distribution of mainland China. The populations exhibited low levels of genetic diversity (nSSR: AR = 1.75, Ho = 0.32, He = 0.36; cpSSR: Nb = 2.01, Hrs = 0.40), and no significant effect of isolation by distance between populations existed, regardless of marker type (nSSR: R2 = 0.0401, P = 0.068; cpSSR: R2 = 0.033, P = 0.091). Haplotype networks showed complex relationships among populations, and the H12 haplotype was predominant in most populations. Analyses of molecular variance obtained with nuclear markers (Fsc = 0.293, FST = 0.362) and chloroplast markers (Fsc = 0.299, FST = 0.312) were similar. The migration ratio of pollen flow versus seed flow in this study was negative (r = −1.149). Results suggest that weak barriers of dispersal between populations and/or the similarity of founders shared between neighbors and distant populations are indicative of the gene flow between populations more likely involving seeds. Wild L. glauca in mainland China was inferred to have highly skewed sex ratios with predominant females. In addition, some populations experienced a recent bottleneck effect, especially in Gujianshan, Chongqing, and southwest China (population GJS). It is suggested that few wild male individuals should be conserved in order to maintain overall genetic diversity in the wild populations of this species. These findings provide important information for the sustainable utilization and preservation of the overall genetic diversity of L. glauca.

scholarly journals A Pre-Vaccination Baseline of SARS-CoV-2 Genetic Surveillance and Diversity in the United States

Viruses ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 104
Author(s):  
Adam A. Capoferri ◽  
Wei Shao ◽  
Jon Spindler ◽  
John M. Coffin ◽  
Jason W. Rausch ◽  
...  
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Rna Virus ◽  
Viral Evolution ◽  
The United States ◽  
Virus Spread ◽  
Immune Pressure ◽  
Viral Genetic Diversity ◽  
Genetic Sampling ◽  
The U.S

COVID-19 vaccines were first administered on 15 December 2020, marking an important transition point for the spread of SARS-CoV-2 in the United States (U.S.). Prior to this point in time, the virus spread to an almost completely immunologically naïve population, whereas subsequently, vaccine-induced immune pressure and prior infections might be expected to influence viral evolution. Accordingly, we conducted a study to characterize the spread of SARS-CoV-2 in the U.S. pre-vaccination, investigate the depth and uniformity of genetic surveillance during this period, and measure and otherwise characterize changing viral genetic diversity, including by comparison with more recently emergent variants of concern (VOCs). In 2020, SARS-CoV-2 spread across the U.S. in three phases distinguishable by peaks in the numbers of infections and shifting geographical distributions. Virus was genetically sampled during this period at an overall rate of ~1.2%, though there was a substantial mismatch between case rates and genetic sampling nationwide. Viral genetic diversity tripled over this period but remained low in comparison to other widespread RNA virus pathogens, and although 54 amino acid changes were detected at frequencies exceeding 5%, linkage among them was not observed. Based on our collective observations, our analysis supports a targeted strategy for worldwide genetic surveillance as perhaps the most sensitive and efficient means of detecting new VOCs.

scholarly journals Single Nucleotide Polymorphisms and Indel Markers from the Transcriptome of Garlic

2016 ◽  
Vol 141 (1) ◽  
pp. 62-65 ◽  
Author(s):  
Michael J. Havey ◽  
Yul-Kyun Ahn
Keyword(s):  
Genetic Diversity ◽  
Molecular Markers ◽  
Single Nucleotide Polymorphisms ◽  
Nucleotide Polymorphisms ◽  
Phenotypic Characteristics ◽  
Single Nucleotide ◽  
Germplasm Collections ◽  
Indel Markers ◽  
Production Environments ◽  
Culinary Uses

Garlic (Allium sativum) is cultivated worldwide and appreciated for its culinary uses. In spite of primarily being asexually propagated, garlic shows great morphological variation and adaptability to diverse production environments. Molecular markers and phenotypic characteristics have been used to assess the genetic diversity among garlics. In this study, we undertook transcriptome sequencing from a single garlic plant to identify molecular markers in expressed regions of the garlic genome. Garlic sequences were assembled and selected if they were similar to monomorphic sequences from a doubled haploid (DH) of onion (Allium cepa). Single nucleotide polymorphisms (SNPs) and insertion–deletion (indel) events were identified in 4355 independent garlic assemblies. A sample of the indels was verified using the original complementary DNA (cDNA) library and genomics DNAs from diverse garlics, and segregations confirmed by sexual progenies of garlic. These molecular markers from the garlic transcriptome should be useful for estimates of genetic diversity, identification and removal of duplicate accessions from germplasm collections, and the development of a detailed genetic map of this important vegetable crop.

scholarly journals Evolution of recombination in eutherian mammals: insights into mechanisms that affect recombination rates and crossover interference

2013 ◽  
Vol 280 (1771) ◽  
pp. 20131945 ◽  
Author(s):  
Joana Segura ◽  
Luca Ferretti ◽  
Sebastián Ramos-Onsins ◽  
Laia Capilla ◽  
Marta Farré ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Mammalian Species ◽  
Evolutionary Change ◽  
Critical Importance ◽  
Recombination Rates ◽  
Allelic Variants ◽  
Crossover Interference ◽  
Chromosomal Segregation ◽  
Low Levels ◽  
Taxonomic Groups

Recombination allows faithful chromosomal segregation during meiosis and contributes to the production of new heritable allelic variants that are essential for the maintenance of genetic diversity. Therefore, an appreciation of how this variation is created and maintained is of critical importance to our understanding of biodiversity and evolutionary change. Here, we analysed the recombination features from species representing the major eutherian taxonomic groups Afrotheria, Rodentia, Primates and Carnivora to better understand the dynamics of mammalian recombination. Our results suggest a phylogenetic component in recombination rates (RRs), which appears to be directional, strongly punctuated and subject to selection. Species that diversified earlier in the evolutionary tree have lower RRs than those from more derived phylogenetic branches. Furthermore, chromosome-specific recombination maps in distantly related taxa show that crossover interference is especially weak in the species with highest RRs detected thus far, the tiger. This is the first example of a mammalian species exhibiting such low levels of crossover interference, highlighting the uniqueness of this species and its relevance for the study of the mechanisms controlling crossover formation, distribution and resolution.

scholarly journals Genetic diversity in different populations of sloths assessed by DNA fingerprinting

2002 ◽  
Vol 62 (3) ◽  
pp. 503-508 ◽  
Author(s):  
N. MORAES ◽  
J. S. MORGANTE ◽  
C. Y. MIYAKI
Keyword(s):  
Genetic Diversity ◽  
Genetic Variability ◽  
Dna Fingerprinting ◽  
Genetic Similarity ◽  
Similarity Indices ◽  
Different Populations ◽  
Related Individuals ◽  
Low Levels ◽  
Dna Profiles ◽  
Two Populations

In this study we analyzed a population of Bradypus torquatus with individuals originally distributed in different localities of Bahia, and two populations of B. variegatus with individuals from Bahia and São Paulo States. Using the DNA fingerprinting method, we assessed the genetic variability within and between populations. Analysis of the DNA profiles revealed genetic similarity indices ranging from 0.34 ± 0.07 to 0.87 ± 0.04. Similar low levels of genetic variability were found only in isolated mammalian populations or among related individuals. This study presents the first analyses of genetic diversity in sloth populations.

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