scholarly journals The dynamics of molecular evolution of emerging avian reoviruses through accumulation of point mutations and genetic re-assortment

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Lisanework E Ayalew ◽  
Khawaja Ashfaque Ahmed ◽  
Zelalem H Mekuria ◽  
Betty Lockerbie ◽  
Shelly Popowich ◽  
...  
Keyword(s):  
Molecular Evolution ◽  
Control Strategies ◽  
Point Mutations ◽  
Sequence Divergence ◽  
Whole Genome ◽  
Poultry Industry ◽  
Diversifying Selection ◽  
A Genome ◽  
New Findings ◽  
Codon Positions

Abstract In the last decade, the emergence of variant strains of avian reovirus (ARV) has caused enormous economic impact in the poultry industry across Canada and USA. ARVs are non-enveloped viruses with ten segments of double-stranded RNA genome. So far, only six genotyping cluster groups are identified worldwide based on sequence analysis of the σC protein encoded by the S1 segment. In this study, we performed deep next generation whole-genome sequencing and analysis of twelve purified ARVs isolated from Saskatchewan, Canada. The viruses represent different genotyping cluster. A genome-wide sequence divergence of up to 25 per cent was observed between the virus isolates with a comparable and contrasting evolutionary history. The proportion of synonymous single-nucleotide variations (sSNVs) was higher than the non-synonymous (ns) SNVs across all the genomic segments. Genomic segment S1 was the most variable as compared with the other genes followed by segment M2. Evidence of positive episodic/diversifying selection was observed at different codon positions in the σC protein sequence, which is the genetic marker for the classification of ARV genotypes. In addition, the N-terminus of σC protein had a persuasive diversifying selection, which was not detected in other genomic segments. We identified only four ARV genotypes based on the most variable σC gene sequence. However, a different pattern of phylogenetic clustering was observed with concatenated whole-genome sequences. Together with the accumulation of point mutations, multiple re-assortment events appeared as mechanisms of ARV evolution. For the first time, we determined the mean rate of molecular evolution of ARVs, which was computed as 2.3 × 10−3 substitution/site/year. In addition, widespread geographic intermixing of ARVs was observed between Canada and USA, and between different countries of the world. In conclusion, the study provides a comprehensive analysis of the complete genome of different genotyping clusters of ARVs including their molecular rate of evolution and spatial distribution. The new findings in this study can be utilized for the development of effective vaccines and other control strategies against ARV-induced arthritis/tenosynovitis in the poultry industry worldwide.

scholarly journals Distinguishing successive ancient polyploidy levels based on genome-internal syntenic alignment

2019 ◽  
Vol 20 (S20) ◽  
Author(s):  
Yue Zhang ◽  
Chunfang Zheng ◽  
David Sankoff
Keyword(s):  
Branching Process ◽  
Sequence Divergence ◽  
Duplicate Gene ◽  
Original Data ◽  
Whole Genome ◽  
Local Maxima ◽  
Genome Doubling ◽  
Model Combining ◽  
A Genome ◽  
History Of

Abstract Background A basic tool for studying the polyploidization history of a genome, especially in plants, is the distribution of duplicate gene similarities in syntenically aligned regions of a genome. This distribution can usually be decomposed into two or more components identifiable by peaks, or local maxima, each representing a different polyploidization event. The distributions may be generated by means of a discrete time branching process, followed by a sequence divergence model. The branching process, as well as the inference of fractionation rates based on it, requires knowledge of the ploidy level of each event, which cannot be directly inferred from the pair similarity distribution. Results For a sequence of two events of unknown ploidy, either tetraploid, giving rise to whole genome doubling (WGD), or hexaploid, giving rise to whole genome tripling (WGT), we base our analysis on triples of similar genes. We calculate the probability of the four triplet types with origins in one or the other event, or both, and impose a mutational model so that the distribution resembles the original data. Using a ML transition point in the similarities between the two events as a discriminator for the hypothesized origin of each similarity, we calculate the predicted number of triplets of each type for each model combining WGT and/or WGD. This yields a predicted profile of triplet types for each model. We compare the observed and predicted triplet profiles for each model to confirm the polyploidization history of durian, poplar and cabbage. Conclusions We have developed a way of inferring the ploidy of up to three successive WGD and/or WGT events by estimating the time of origin of each of the similarities in triples of genes. This may be generalized to a larger number of events and to higher ploidies.

scholarly journals Global Analysis of Furfural-Induced Genomic Instability Using a Yeast Model

2019 ◽  
Vol 85 (18) ◽  
Author(s):  
Lei Qi ◽  
Ke Zhang ◽  
Yu-Ting Wang ◽  
Jian-Kun Wu ◽  
Yang Sui ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Global Analysis ◽  
Chromosomal Rearrangements ◽  
Point Mutations ◽  
Mitotic Recombination ◽  
Whole Genome ◽  
Wild Type ◽  
Content Type ◽  
A Genome

ABSTRACT Furfural is an important renewable precursor for multiple commercial chemicals and fuels; a main inhibitor existing in cellulosic hydrolysate, which is used for bioethanol fermentation; and a potential carcinogen, as well. Using a genetic system in Saccharomyces cerevisiae that allows detection of crossover events, we observed that the frequency of mitotic recombination was elevated by 1.5- to 40-fold when cells were treated with 0.1 g/liter to 20 g/liter furfural. Analysis of the gene conversion tracts associated with crossover events suggested that most furfural-induced recombination resulted from repair of DNA double-strand breaks (DSBs) that occurred in the G1 phase. Furfural was incapable of breaking DNA directly in vitro but could trigger DSBs in vivo related to reactive oxygen species accumulation. By whole-genome single nucleotide polymorphism (SNP) microarray and sequencing, furfural-induced genomic alterations that range from single base substitutions, loss of heterozygosity, and chromosomal rearrangements to aneuploidy were explored. At the whole-genome level, furfural-induced events were evenly distributed across 16 chromosomes but were enriched in high-GC-content regions. Point mutations, particularly the C-to-T/G-to-A transitions, were significantly elevated in furfural-treated cells compared to wild-type cells. This study provided multiple novel insights into the global effects of furfural on genomic stability. IMPORTANCE Whether and how furfural affects genome integrity have not been clarified. Using a Saccharomyces cerevisiae model, we found that furfural exposure leads to in vivo DSBs and elevation in mitotic recombination by orders of magnitude. Gross chromosomal rearrangements and aneuploidy events also occurred at a higher frequency in furfural-treated cells. In a genome-wide analysis, we show that the patterns of mitotic recombination and point mutations differed dramatically in furfural-treated cells and wild-type cells.

scholarly journals Structural characterization and duplication modes of pseudogenes in plants

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Flavia Mascagni ◽  
Gabriele Usai ◽  
Andrea Cavallini ◽  
Andrea Porceddu
Keyword(s):  
Evolutionary Rate ◽  
Populus Trichocarpa ◽  
Sequence Divergence ◽  
Strand Break ◽  
Whole Genome ◽  
Flanking Sequence ◽  
Plant Genomes ◽  
High Sequence Divergence ◽  
Flanking Regions

AbstractWe identified and characterized the pseudogene complements of five plant species: four dicots (Arabidopsis thaliana, Vitis vinifera, Populus trichocarpa and Phaseolus vulgaris) and one monocot (Oryza sativa). Retroposition was considered of modest importance for pseudogene formation in all investigated species except V. vinifera, which showed an unusually high number of retro-pseudogenes in non coding genic regions. By using a pipeline for the classification of sequence duplicates in plant genomes, we compared the relative importance of whole genome, tandem, proximal, transposed and dispersed duplication modes in the pseudo and functional gene complements. Pseudogenes showed higher tendencies than functional genes to genomic dispersion. Dispersed pseudogenes were prevalently fragmented and showed high sequence divergence at flanking regions. On the contrary, those deriving from whole genome duplication were proportionally less than expected based on observations on functional loci and showed higher levels of flanking sequence conservation than dispersed pseudogenes. Pseudogenes deriving from tandem and proximal duplications were in excess compared to functional loci, probably reflecting the high evolutionary rate associated with these duplication modes in plant genomes. These data are compatible with high rates of sequence turnover at neutral sites and double strand break repairs mediated duplication mechanisms.

scholarly journals Genomic diversity of Mycobacterium avium subsp. paratuberculosis: pangenomic approach for highlighting unique genomic features with newly constructed complete genomes

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Jaewon Lim ◽  
Hong-Tae Park ◽  
Seyoung Ko ◽  
Hyun-Eui Park ◽  
Gyumin Lee ◽  
...  
Keyword(s):  
Mycobacterium Avium ◽  
Phenotypic Diversity ◽  
Control Strategies ◽  
Genomic Diversity ◽  
Phenotypic Traits ◽  
Whole Genome ◽  
Genomic Features ◽  
Phenotypic Differences ◽  
Mycobacterium Avium Subsp Paratuberculosis ◽  
Type Strains

AbstractMycobacterium avium subsp. paratuberculosis (MAP) is a causative agent of Johne’s disease, which is a chronic granulomatous enteropathy in ruminants. Determining the genetic diversity of MAP is necessary to understand the epidemiology and biology of MAP, as well as establishing disease control strategies. In the present study, whole genome-based alignment and comparative analysis were performed using 40 publicly available MAP genomes, including newly sequenced Korean isolates. First, whole genome-based alignment was employed to identify new genomic structures in MAP genomes. Second, the genomic diversity of the MAP population was described by pangenome analysis. A phylogenetic tree based on the core genome and pangenome showed that the MAP was differentiated into two major types (C- and S-type), which was in keeping with the findings of previous studies. However, B-type strains were discriminated from C-type strains. Finally, functional analysis of the pangenome was performed using three virulence factor databases (i.e., PATRIC, VFDB, and Victors) to predict the phenotypic diversity of MAP in terms of pathogenicity. Based on the results of the pangenome analysis, we developed a real-time PCR technique to distinguish among S-, B- and C-type strains. In conclusion, the results of our study suggest that the phenotypic differences between MAP strains can be explained by their genetic polymorphisms. These results may help to elucidate the diversity of MAP, extending from genomic features to phenotypic traits.

Demographic history and patterns of molecular evolution from whole genome sequencing in the radiation of Galapagos giant tortoises

2021 ◽  
Author(s):  
Evelyn L. Jensen ◽  
Stephen J. Gaughran ◽  
Ryan C. Garrick ◽  
Michael A. Russello ◽  
Adalgisa Caccone
Keyword(s):  
Molecular Evolution ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Demographic History ◽  
Whole Genome

scholarly journals Molecular characterization of glucose-6-phosphate dehydrogenase (G6PD) deficiency in patients of Chinese descent and identification of new base substitutions in the human G6PD gene

Blood ◽  
1993 ◽  
Vol 81 (8) ◽  
pp. 2150-2154 ◽  
Author(s):  
DT Chiu ◽  
L Zuo ◽  
L Chao ◽  
E Chen ◽  
E Louie ◽  
...  
Keyword(s):  
G6pd Deficiency ◽  
Point Mutations ◽  
Nucleotide Substitutions ◽  
New Findings ◽  
G6pd Gene ◽  
High Prevalence ◽  
Chinese Descent ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Sequencing Procedure

Abstract The underlying DNA changes associated with glucose-6-phosphate dehydrogenase (G6PD)-deficient Asians have not been extensively investigated. To fill this gap, we sequenced the G6PD gene of 43 G6PD- deficient Chinese whose G6PD was well characterized biochemically. DNA samples were obtained from peripheral blood of these individuals for sequencing using a direct polymerase chain reaction (PCR) sequencing procedure. From these 43 samples, we have identified five different types of nucleotide substitutions in the G6PD gene: at cDNA 1388 from G to A (Arg to His); at cDNA 1376 from G to T (Arg to Leu); at cDNA 1024 from C to T (Leu to Phe); at cDNA 392 from G to T (Gly to Val); at cDNA 95 from A to G (His to Arg). These five nucleotide substitutions account for over 83% of our 43 G6PD-deficient samples and these substitutions have not been reported in non-Asians. The substitutions found at cDNA 392 and cDNA 1024 are new findings. The substitutions at cDNA 1376 and 1388 account for over 50% of the 43 samples examined indicating a high prevalence of these two alleles among G6PD-deficient Chinese. Our findings add support to the notion that diverse point mutations may account largely for much of the phenotypic heterogeneity of G6PD deficiency.

Calreticulin molecular evolution: a strong purifying and episodic diversifying selection result

Biologia ◽  
2014 ◽  
Vol 69 (3) ◽  
Author(s):  
Rigers Bakiu
Keyword(s):  
Molecular Evolution ◽  
Higher Plants ◽  
Phylogenetic Analyses ◽  
Purifying Selection ◽  
Amino Acid Sequences ◽  
Over Expression ◽  
Diversifying Selection ◽  
Pathological Conditions ◽  
Weight Protein ◽  
Low Molecular Weight Protein

AbstractCalreticulin (CRT) is a low molecular weight protein present in vertebrates, invertebrates and higher plants. Its multiple functions have been demonstrated. It plays an important role as a chaperone and Ca2+ buffer inside sarcoplasmic/endoplasmic reticulum (SR/ER), and outside the ER in many physiological/pathological processes. Recently it has been observed that CRT over-expression or its absence is linked to various pathological conditions, such as malignant evolution and progression, and these facts really increased its study interests. Using an evolution approach CRT was further characterized. Several Bayesian phylogenetic analyses were performed using coding and amino acid sequences. CRT molecular evolution was investigated for the presence of negative or/and positive selection using HyPhy package. The results indicated that the purifying selection might have operated over the whole CRT primary structure. Although, an episodic diversifying selection was also found on the analyzed CRT sequences.

Evolutionary Analyses of Protein Interaction Networks

2009 ◽  
pp. 169-181 ◽  
Author(s):  
Takashi Makino ◽  
Aoife McLysaght
Keyword(s):  
Molecular Evolution ◽  
Comparative Genomics ◽  
Protein Interaction ◽  
Protein Interaction Networks ◽  
Evolutionary Rates ◽  
Interaction Networks ◽  
Evolutionary Mechanisms ◽  
Ancestral Gene ◽  
Protein Protein Interaction ◽  
A Genome

This chapter introduces evolutionary analyses of protein interaction networks and of proteins as components of the networks. The authors show relationships between proteins in the networks and their evolutionary rates. For understanding protein-protein interaction (PPI) divergence, duplicated genes are often compared because they are derived from a common ancestral gene. In order to reveal evolutionary mechanisms acting on the interactome it is necessary to compare PPIs across species. Investigation of co-localization of interacting genes in a genome shows that PPIs have an important role in the maintenance of a physical link between neighboring genes. The purpose of this chapter is to introduce methodologies for analyzing PPI data and to describe molecular evolution and comparative genomics insights gained from such studies.

scholarly journals Efficient and accurate determination of genome-wide DNA methylation patterns in Arabidopsis thaliana with enzymatic methyl sequencing

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Suhua Feng ◽  
Zhenhui Zhong ◽  
Ming Wang ◽  
Steven E. Jacobsen
Keyword(s):  
Dna Methylation ◽  
Bisulfite Sequencing ◽  
Accurate Determination ◽  
Gc Content ◽  
Epigenetic Mark ◽  
Whole Genome ◽  
Whole Genome Bisulfite Sequencing ◽  
Genome Wide ◽  
A Genome ◽  
Genome Bisulfite Sequencing

Abstract Background 5′ methylation of cytosines in DNA molecules is an important epigenetic mark in eukaryotes. Bisulfite sequencing is the gold standard of DNA methylation detection, and whole-genome bisulfite sequencing (WGBS) has been widely used to detect methylation at single-nucleotide resolution on a genome-wide scale. However, sodium bisulfite is known to severely degrade DNA, which, in combination with biases introduced during PCR amplification, leads to unbalanced base representation in the final sequencing libraries. Enzymatic conversion of unmethylated cytosines to uracils can achieve the same end product for sequencing as does bisulfite treatment and does not affect the integrity of the DNA; enzymatic methylation sequencing may, thus, provide advantages over bisulfite sequencing. Results Using an enzymatic methyl-seq (EM-seq) technique to selectively deaminate unmethylated cytosines to uracils, we generated and sequenced libraries based on different amounts of Arabidopsis input DNA and different numbers of PCR cycles, and compared these data to results from traditional whole-genome bisulfite sequencing. We found that EM-seq libraries were more consistent between replicates and had higher mapping and lower duplication rates, lower background noise, higher average coverage, and higher coverage of total cytosines. Differential methylation region (DMR) analysis showed that WGBS tended to over-estimate methylation levels especially in CHG and CHH contexts, whereas EM-seq detected higher CG methylation levels in certain highly methylated areas. These phenomena can be mostly explained by a correlation of WGBS methylation estimation with GC content and methylated cytosine density. We used EM-seq to compare methylation between leaves and flowers, and found that CHG methylation level is greatly elevated in flowers, especially in pericentromeric regions. Conclusion We suggest that EM-seq is a more accurate and reliable approach than WGBS to detect methylation. Compared to WGBS, the results of EM-seq are less affected by differences in library preparation conditions or by the skewed base composition in the converted DNA. It may therefore be more desirable to use EM-seq in methylation studies.

scholarly journals Fine Mapping Using Whole-Genome Sequencing Confirms Anti-Müllerian Hormone as a Major Gene for Sex Determination in Farmed Nile Tilapia (Oreochromis niloticus L.)

2019 ◽  
Vol 9 (10) ◽  
pp. 3213-3223 ◽  
Author(s):  
Giovanna Cáceres ◽  
María E. López ◽  
María I. Cádiz ◽  
Grazyella M. Yoshida ◽  
Ana Jedlicki ◽  
...  
Keyword(s):  
Sex Determination ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Major Gene ◽  
Whole Genome ◽  
Important Species ◽  
Genome Wide ◽  
A Genome

Nile tilapia (Oreochromis niloticus) is one of the most cultivated and economically important species in world aquaculture. Intensive production promotes the use of monosex animals, due to an important dimorphism that favors male growth. Currently, the main mechanism to obtain all-male populations is the use of hormones in feeding during larval and fry phases. Identifying genomic regions associated with sex determination in Nile tilapia is a research topic of great interest. The objective of this study was to identify genomic variants associated with sex determination in three commercial populations of Nile tilapia. Whole-genome sequencing of 326 individuals was performed, and a total of 2.4 million high-quality bi-allelic single nucleotide polymorphisms (SNPs) were identified after quality control. A genome-wide association study (GWAS) was conducted to identify markers associated with the binary sex trait (males = 1; females = 0). A mixed logistic regression GWAS model was fitted and a genome-wide significant signal comprising 36 SNPs, spanning a genomic region of 536 kb in chromosome 23 was identified. Ten out of these 36 genetic variants intercept the anti-Müllerian (Amh) hormone gene. Other significant SNPs were located in the neighboring Amh gene region. This gene has been strongly associated with sex determination in several vertebrate species, playing an essential role in the differentiation of male and female reproductive tissue in early stages of development. This finding provides useful information to better understand the genetic mechanisms underlying sex determination in Nile tilapia.

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