scholarly journals Selection on codon usage and base composition in Drosophila americana

2011 ◽  
Vol 8 (1) ◽  
pp. 82-85 ◽  
Author(s):  
Sophie Marion de Procé ◽  
Kai Zeng ◽  
Andrea J. Betancourt ◽  
Brian Charlesworth
Keyword(s):  
Natural Selection ◽  
Codon Usage ◽  
Base Composition ◽  
Maximum Likelihood Method ◽  
Demographic History ◽  
Population Expansion ◽  
Likelihood Method ◽  
Recent Population Expansion ◽  
Coding Sequences ◽  
Biased Gene Conversion

We have used a polymorphism dataset on introns and coding sequences of X-linked loci in Drosophila americana to estimate the strength of selection on codon usage and/or biased gene conversion (BGC), taking into account a recent population expansion detected by a maximum-likelihood method. Drosophila americana was previously thought to have a stable demographic history, so that this evidence for a recent population expansion means that previous estimates of selection need revision. There was evidence for natural selection or BGC favouring GC over AT variants in introns, which is stronger for GC-rich than GC-poor introns. By comparing introns and coding sequences, we found evidence for selection on codon usage bias, which is much stronger than the forces acting on GC versus AT basepairs in introns.

scholarly journals Recent population expansion of longtail tuna Thunnus tonggol (Bleeker, 1851) inferred from the mitochondrial DNA markers

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9679
Author(s):  
Noorhani Syahida Kasim ◽  
Tun Nurul Aimi Mat Jaafar ◽  
Rumeaida Mat Piah ◽  
Wahidah Mohd Arshaad ◽  
Siti Azizah Mohd Nor ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Pacific Ocean ◽  
Goodness Of Fit ◽  
Demographic History ◽  
Population Expansion ◽  
Seasonal Migration ◽  
Likelihood Method ◽  
Recent Population Expansion ◽  
D Loop ◽  
Longtail Tuna

The population genetic diversity and demographic history of the longtail tuna Thunnus tonggol in Malaysian waters was investigated using mitochondrial DNA D-loop and NADH dehydrogenase subunit 5 (ND5). A total of 203 (D-loop) and 208 (ND5) individuals of T. tonggol were sampled from 11 localities around the Malaysian coastal waters. Low genetic differentiation between populations was found, possibly due to the past demographic history, dispersal potential during egg and larval stages, seasonal migration in adults, and lack of geographical barriers. The gene trees, constructed based on the maximum likelihood method, revealed a single panmictic population with unsupported internal clades, indicating an absence of structure among the populations studied. Analysis on population pairwise comparison ФST suggested the absence of limited gene flow among study sites. Taken all together, high haplotype diversity (D-loop = 0.989–1.000; ND5 = 0.848–0.965), coupled with a low level of nucleotide diversity (D-loop = 0.019–0.025; ND5 = 0.0017–0.003), “star-like” haplotype network, and unimodal mismatch distribution, suggests a recent population expansion for populations of T. tonggol in Malaysia. Furthermore, neutrality and goodness of fit tests supported the signature of a relatively recent population expansion during the Pleistocene epoch. To provide additional insight into the phylogeographic pattern of the species within the Indo-Pacific Ocean, we included haplotypes from GenBank and a few samples from Taiwan. Preliminary analyses suggest a more complex genetic demarcation of the species than an explicit Indian Ocean versus Pacific Ocean delineation.

Phylogenetic Analysis of Black Peper (Piper Spp.) Population Collected in Different Locations of Vietnam Based on the ITSU1-4 Gene Region

2021 ◽  
Author(s):  
Sonexay Rasphone ◽  
Long Thanh Dang ◽  
Hoan Nguyen ◽  
Ngoc Quang Nguyen ◽  
Oanh Thi Duong ◽  
...  
Keyword(s):  
Dna Barcoding ◽  
Ribosomal Dna ◽  
Maximum Likelihood Method ◽  
Dna Barcode ◽  
Population Expansion ◽  
Nuclear Ribosomal Dna ◽  
Likelihood Method ◽  
Gene Region ◽  
Universal Primers ◽  
Intraspecific Distance

Abstract Background: The internal transcribed spacer (ITS) of nuclear ribosomal DNA is one of the most commonly used DNA markers in plant phylogenetic and DNA barcoding analyses, and it has been recommended as a core plant DNA barcode. To compare and find out the analysis genetic diversity difference some pepper individuals collected in different localities in Vietnam when using the ITS of nuclear ribosomal DNA. The ITS gene region from the nuclear genomes were tested for their suitability as DNA barcoding regions of thirty-nine pepper individuals. Universal primers were used, and sequenced products were analyzed using the Maximum Likelihood method and Tamura-Nei model in the MEGA X program.Results: We did not observe high variability in intraspecific distance within the ITSu1-4 gene region between individuals, ranged from 0.000 to 0.155 (mean = 0.033). The size of the gene region has fluctuated from 667 to 685 bp between different individuals with the percentage (G + C) contained in the ITSu1-4 gene region was ranged from 54.776% to 60.805%, mean = 60.174%. The values of Fu’s Fs, D, Fu and Li’s D* and F* were negative as well (Fs = -0.209, D = -1.824; P < 0.05, D* = -1.205; not significant, P > 0.10 and F* = -1.699; not significant, 0.10 > P > 0.05), indicating an excess of recently derived haplotypes and suggesting that either population expansion or background selection has occurred. The value Strobeck’s S the obtained between individuals in a population is high (S = 0.684). The results of evolutionary relationships of taxa obtained 3 groups with the highest value of Fst is shown in the pairs of groups II and III (Fst = 0.151), and the lowest is in groups II and I (Fst = 0.015). All of the new sequences have been deposited in GeneBank under the following accession numbers MZ636718 to MZ636756.Conclusions: This database is an important resource for researchers working on Species of pepper in Vietnam and also provides a tool to create ITSu1-4 databases for any given taxonomy.

scholarly journals Intragenomic variation in mutation biases causes underestimation of selection on synonymous codon usage

2021 ◽  
Author(s):  
Alexander L Cope ◽  
Premal Shah
Keyword(s):  
Population Genetics ◽  
Natural Selection ◽  
Codon Usage ◽  
Codon Bias ◽  
Synonymous Codon ◽  
Synonymous Codon Usage ◽  
Mutation Bias ◽  
Biased Gene Conversion ◽  
Intragenomic Variation ◽  
The Impact

Patterns of non-uniform usage of synonymous codons (codon bias) varies across genes in an organism and across species from all domains of life. The bias in codon usage is due to a combination of both non-adaptive (e.g. mutation biases) and adaptive (e.g. natural selection for translation efficiency/accuracy) evolutionary forces. Most population genetics models quantify the effects of mutation bias and selection on shaping codon usage patterns assuming a uniform mutation bias across the genome. However, mutation biases can vary both along and across chromosomes due to processes such as biased gene conversion, potentially obfuscating signals of translational selection. Moreover, estimates of variation in genomic mutation biases are often lacking for non-model organisms. Here, we combine an unsupervised learning method with a population genetics model of synonymous codon bias evolution to assess the impact of intragenomic variation in mutation bias on the strength and direction of natural selection on synonymous codon usage across 49 Saccharomycotina budding yeasts. We find that in the absence of a priori information, unsupervised learning approaches can be used to identify regions evolving under different mutation biases. We find that the impact of intragenomic variation in mutation bias varies widely, even among closely-related species. We show that the overall strength and direction of selection on codon usage can be underestimated by failing to account for intragenomic variation in mutation biases. Interestingly, genes falling into clusters identified by machine learning are also often physically clustered across chromosomes, consistent with processes such as biased gene conversion. Our results indicate the need for more nuanced models of sequence evolution that systematically incorporate the effects of variable mutation biases on codon frequencies.

scholarly journals Codon Usage Bias in Animals: Disentangling the Effects of Natural Selection, Effective Population Size, and GC-Biased Gene Conversion

2018 ◽  
Vol 35 (5) ◽  
pp. 1092-1103 ◽  
Author(s):  
Nicolas Galtier ◽  
Camille Roux ◽  
Marjolaine Rousselle ◽  
Jonathan Romiguier ◽  
Emeric Figuet ◽  
...  
Keyword(s):  
Natural Selection ◽  
Codon Usage ◽  
Population Size ◽  
Gene Conversion ◽  
Effective Population Size ◽  
Codon Usage Bias ◽  
Effective Population ◽  
Biased Gene Conversion

scholarly journals Mitochondrial phylogeography of the Mediterranean horseshoe bat on the Balkan Peninsula

2019 ◽  
Vol 71 (4) ◽  
pp. 767-774
Author(s):  
Ivana Budinski ◽  
Vladimir Jovanovic ◽  
Branka Pejic ◽  
Jelena Blagojevic ◽  
Marija Rajicic ◽  
...  
Keyword(s):  
Demographic History ◽  
Haplotype Diversity ◽  
Population Expansion ◽  
Balkan Peninsula ◽  
Glacial Refugium ◽  
Recent Population Expansion ◽  
The Balkans ◽  
Loop Region ◽  
The Mediterranean ◽  
Horseshoe Bat

The Balkan Peninsula is identified as one of the major glacial refugia in Europe during the Pleistocene, and it has served as a genetic source for post-glacial recolonization for many temperate species. The aim of this study was to investigate the genetic diversity and phylogeographic patterns of the Mediterranean horseshoe bat, Rhinolophus euryale Blasius 1853, on the Balkan Peninsula. We also analyzed its demographic history and tested the hypothesis that this region was a glacial refugium for this species. We collected 82 samples from 20 localities in the Balkans and Italy and sequenced the mitochondrial D-loop region. Our results revealed low nucleotide but high haplotype diversity, with 20 out of 24 haplotypes reported for the first time. All Balkan and Italian samples belonged to a single genetic clade in the phylogenetic reconstruction, where they clustered together with previously published samples from Turkey, southern France and North Africa. The haplotype network had a star-like pattern that is indicative of recent population expansion. Both mismatch distribution and shallow genetic differentiation also supported the scenario of a sudden demographic expansion. We estimated that expansion within this lineage commenced in the Late Pleistocene. We suggest that the Balkan Peninsula was a glacial refugium for R. euryale.

scholarly journals Analysis of Synonymous Codon Usage Bias in Potato Virus M and Its Adaption to Hosts

Viruses ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 752 ◽  
Author(s):  
Zhen He ◽  
Haifeng Gan ◽  
Xinyan Liang
Keyword(s):  
Natural Selection ◽  
Codon Usage ◽  
Potato Virus ◽  
Synonymous Codon ◽  
Synonymous Codon Usage ◽  
Economic Losses ◽  
Codon Usage Pattern ◽  
Usage Pattern ◽  
Coding Sequences ◽  
Potato Virus M

Potato virus M (PVM) is a member of the genus Carlavirus of the family Betaflexviridae and causes large economic losses of nightshade crops. Several previous studies have elucidated the population structure, evolutionary timescale and adaptive evolution of PVM. However, the synonymous codon usage pattern of PVM remains unclear. In this study, we performed comprehensive analyses of the codon usage and composition of PVM based on 152 nucleotide sequences of the coat protein (CP) gene and 125 sequences of the cysteine-rich nucleic acid binding protein (NABP) gene. We observed that the PVM CP and NABP coding sequences were GC-and AU-rich, respectively, whereas U- and G-ending codons were preferred in the PVM CP and NABP coding sequences. The lower codon usage of the PVM CP and NABP coding sequences indicated a relatively stable and conserved genomic composition. Natural selection and mutation pressure shaped the codon usage patterns of PVM, with natural selection being the most important factor. The codon adaptation index (CAI) and relative codon deoptimization index (RCDI) analysis revealed that the greatest adaption of PVM was to pepino, followed by tomato and potato. Moreover, similarity Index (SiD) analysis showed that pepino had a greater impact on PVM than tomato and potato. Our study is the first attempt to evaluate the codon usage pattern of the PVM CP and NABP genes to better understand the evolutionary changes of a carlavirus.

scholarly journals Genetic Diversity and Demographic History of the Shaggy Soft-Haired Mouse Abrothrix hirta (Cricetidae; Abrotrichini)

2021 ◽  
Vol 12 ◽  
Author(s):  
Lourdes Valdez ◽  
Guillermo D’Elía
Keyword(s):  
Genetic Diversity ◽  
Demographic History ◽  
Population Expansion ◽  
Principal Component ◽  
Tierra Del Fuego ◽  
Local Fauna ◽  
Recent Population Expansion ◽  
Genetic Groups ◽  
History Of ◽  
Species Specific

Genetic information on species can inform decision making regarding conservation of biodiversity since the response of organisms to changing environments depend, in part, on their genetic makeup. Territories of central-southern Chile and Argentina have undergone a varying degree of impact during the Quaternary, where the response of local fauna and flora was rather species-specific. Here, we focus on the sigmodontine rodent Abrothrix hirta, distributed from 35° S in Chile and Argentina to northern Tierra del Fuego. Based on 119,226 transcriptome-derived SNP loci from 46 individuals of A. hirta, we described the geographic distribution of the genetic diversity of this species using a maximum likelihood tree, principal component and admixture analyses. We also addressed the demographic history of the main intraspecific lineages of A. hirta using GADMA. We found that A. hirta exhibited four allopatric intraspecific lineages. Three main genetic groups were identified by a Principal Component Analysis and by Ancestry analysis. The demographic history of A. hirta was characterized by recent population stability for populations at the northernmost part of the range, while southern populations experienced a recent population expansion.

scholarly journals Genetic Diversity and Population Structure of Rhododendron rex Subsp. rex Inferred from Microsatellite Markers and Chloroplast DNA Sequences

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 338 ◽  
Author(s):  
Xue Zhang ◽  
Yuan-Huan Liu ◽  
Yue-Hua Wang ◽  
Shi-Kang Shen
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Microsatellite Markers ◽  
Chloroplast Dna ◽  
Dna Sequences ◽  
Demographic History ◽  
Population Decline ◽  
Population Expansion ◽  
Distribution Models ◽  
Recent Population Expansion

Genetic diversity is vital to the sustainable utilization and conservation of plant species. Rhododendron rex subsp. rex Lévl. is an endangered species endemic to the southwest of China. Although the natural populations of this species are facing continuous decline due to the high frequency of anthropogenic disturbance, the genetic information of R. rex subsp. rex is not yet elucidated. In the present study, 10 pairs of microsatellite markers (nSSRs) and three pairs of chloroplast DNA (cpDNAs) were used in the elucidation of the genetic diversity, population structure, and demographic history of 11 R. rex subsp. rex populations. A total of 236 alleles and 12 haplotypes were found. A moderate genetic diversity within populations (HE = 0.540 for nSSRs, Hd = 0.788 for cpDNA markers), high historical and low contemporary gene flows, and moderate genetic differentiation (nSSR: FST = 0.165***; cpDNA: FST = 0.841***) were detected among the R. rex subsp. rex populations. Genetic and geographic distances showed significant correlation (p < 0.05) determined by the Mantel test. The species exhibited a conspicuous phylogeographical structure among the populations. Using the Bayesian skyline plot and species distribution models, we found that R. rex subsp. rex underwent a population demography contraction approximately 50,000–100,000 years ago. However, the species did not experience a recent population expansion event. Thus, habitat loss and destruction, which result in a population decline and species inbreeding depression, should be considered in the management and conservation of R. rex subsp. rex.

scholarly journals Comprehensive Analysis of Codon Usage Patterns in Chinese Porcine Circoviruses Based on Their Major Protein-Coding Sequences

Viruses ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 81
Author(s):  
Hua Feng ◽  
Joaquim Segalés ◽  
Fangyu Wang ◽  
Qianyue Jin ◽  
Aiping Wang ◽  
...  
Keyword(s):  
Natural Selection ◽  
Codon Usage ◽  
Codon Usage Bias ◽  
Large Scale ◽  
Codon Usage Pattern ◽  
Major Protein ◽  
Mutation Pressure ◽  
Coding Sequences ◽  
Usage Patterns ◽  
Porcine Circoviruses

Porcine circoviruses (PCVs) are distributed in swine herds worldwide and represent a threat to the health of domestic pigs and the profits of the swine industry. Currently, four PCV species, including PCV-1, PCV-2, PCV-3 and PCV-4, have been identified in China. Considering the ubiquitous characteristic of PCVs, the new emerged PCV-4 and the large scale of swine breeding in China, an overall analysis on codon usage bias for Chinese PCV sequences was performed by using the major proteins coding sequences (ORF1 and ORF2) to better understand the relationship of these viruses with their host. The data from genome nucleotide frequency composition and relative synonymous codon usage (RSCU) analysis revealed an overrepresentation of AT pair and the existence of a certain codon usage bias in all PCVs. However, the values of an effective number of codons (ENC) revealed that the bias was of low magnitude. Principal component analysis, ENC-plot, parity rule two analysis and correlation analysis suggested that natural selection and mutation pressure were both involved in the shaping of the codon usage patterns of PCVs. However, a neutrality plot revealed a stronger effect of natural selection than mutation pressure on codon usage patterns. Good host adaptation was also shown by the codon adaptation index analysis for all these viruses. Interestingly, obtained data suggest that PCV-4 might be more adapted to its host compared to other PCVs. The present study obtained insights into the codon usage pattern of PCVs based on ORF1 and ORF2, which further helps the understanding the molecular evolution of these swine viruses.

scholarly journals Assessing the origin, genetic structure and demographic history of the common pheasant (Phasianus colchicus) in the introduced European range

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Reza Ashrafzadeh ◽  
Rasoul Khosravi ◽  
Carlos Fernandes ◽  
Cecilia Aguayo ◽  
Zoltán Bagi ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Demographic History ◽  
Population Expansion ◽  
Game Species ◽  
Recent Population Expansion ◽  
Biogeographic Patterns ◽  
Clustering Model ◽  
History Of ◽  
Common Pheasant ◽  
The Common

AbstractThe common pheasant, a game species widely introduced throughout the world, can be considered as an ideal model to study the effects of introduction events on local adaptations, biogeographic patterns, and genetic divergence processes. We aimed to assess the origin, spatial patterns of genetic variation, and demographic history of the introduced populations in the contact zone of Central and Southeast Europe, using mitochondrial DNA control region sequences and microsatellite loci. Both types of molecular markers indicated relatively low to moderate levels of genetic variation. The mtDNA analyses revealed that common pheasants across the study area are divided into two distinct clades: B (mongolicus group) and F (colchicus group). Analyses of the microsatellite data consistently suggested a differentiation between Hungary and Serbia, with the pheasant population in Hungary being much more genetically homogeneous, while that of Serbia has much more genetic mixture and admixture. This cryptic differentiation was not detected using a non-spatial Bayesian clustering model. The analyses also provided strong evidence for a recent population expansion. This fundamental information is essential for adequate and effective conservation management of populations of a game species of great economic and ecological importance in the studied geographical region.

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