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Over the last few years multiple studies have been published outlining chloroplast genomes that represent many of the photosynthetic euglenid genera. However, these genomes were scattered throughout the euglenophyceaean phylogenetic tree, and focused on comparisons with Euglena gracilis. Here, we present a study exclusively on taxa within the Euglenaceae. Six new chloroplast genomes were characterized, those of Cryptoglena skujai, E. gracilis var. bacillaris, Euglena viridis, Euglenaria anabaena, Monomorphina parapyrum, and Trachelomonas volvocina, and added to six previously published chloroplast genomes to determine if trends existed within the family. With this study: at least one genome has now been characterized for each genus, the genomes of different strains from two taxa were characterized to explore intraspecific variability, and a second taxon has been characterized for the genus Monomorphina to examine intrageneric variability. Overall results showed a large amount of variability among the genomes, though a few trends could be identified both within Euglenaceae and within Euglenophyta. In addition, the intraspecific analysis indicated that the similarity of a genome sequence between strains was taxon dependent, and the intrageneric analysis indicated that the majority of the evolutionary changes within the Euglenaceae occurred intergenerically. 相似文献
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Hana Chaïr Julie Sardos Anthea Supply Pierre Mournet Roger Malapa Vincent Lebot 《Botanical journal of the Linnean Society. Linnean Society of London》2016,180(3):319-333
Phylogenetic relationships of Oceanian staple yams (species of Dioscorea section Enantiophyllum) were investigated using plastid trnL‐F and rpl32‐trnL(UAG) sequences and nine nuclear co‐dominant microsatellites. Analysis of herbarium specimens, used as taxonomic references, allowed the comparison with samples collected in the field. It appears that D. alata, D. transversa and D. hastifolia are closely related species. This study does not support a direct ancestry from D. nummularia to D. alata as previously hypothesized. The dichotomy in D. nummularia previously described by farmers in semi‐perennial and annual types was reflected by molecular markers, but the genetic structure of D. nummularia appears more complex. Dioscorea nummularia displayed two haplotypes, each corresponding to a different genetic group. One, including a D. nummularia voucher from New Guinea, is closer to D. tranversa, D. alata and D. hastifolia and encompasses only semi‐perennial types. The second group is composed of semi‐perennial and annual yams. However, some of these annual yams also displayed D. alata haplotypes. Nuclear markers revealed that some annual yams shared alleles with D. alata and semi‐perennial D. nummularia, suggesting a hybrid origin, which may explain their intermediate morphotypes and the difficulty met in classifying them. 相似文献
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Jianchao Ma Dongshi Wan Bingbing Duan Xiaotao Bai Qiuxian Bai Ningning Chen Tao Ma 《Plant biotechnology journal》2019,17(2):451-460
Populus alba is widely distributed and cultivated in Europe and Asia. This species has been used for diverse studies. In this study, we assembled a de novo genome sequence of P. alba var. pyramidalis (= P. bolleana) and confirmed its high transformation efficiency and short transformation time by experiments. Through a process of hybrid genome assembly, a total of 464 M of the genome was assembled. Annotation analyses predicted 37 901 protein‐coding genes. This genome is highly collinear to that of P. trichocarpa, with most genes having orthologs in the two species. We found a marked expansion of gene families related to histone and the hormone auxin but loss of disease resistance genes in P. alba if compared with the closely related P. trichocarpa. The genome sequence presented here represents a valuable resource for further molecular functional analyses of this species as a new tree model, poplar breeding practices and comparative genomic analyses across different poplars. 相似文献
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Cordelia Bolle Gunnar Huep Nils Kleinbölting Georg Haberer Klaus Mayer Dario Leister Bernd Weisshaar 《The Plant journal : for cell and molecular biology》2013,75(1):157-171
Owing to duplication events in its progenitor, more than 90% of the genes in the Arabidopsis thaliana genome are members of multigene families. A set of 2108 gene families, each consisting of precisely two unlinked paralogous genes, was identified in the nuclear genome of A. thaliana on the basis of sequence similarity. A systematic method for the creation of double knock‐out lines for such gene pairs, designated as DUPLO lines, was established and 200 lines are now publicly available. Their initial phenotypic characterisation led to the identification of seven lines with defects that emerge only in the adult stage. A further six lines display seedling lethality and 23 lines were lethal before germination. Another 14 lines are known to show phenotypes under non‐standard conditions or at the molecular level. Knock‐out of gene pairs with very similar coding sequences or expression profiles is more likely to produce a mutant phenotype than inactivation of gene pairs with dissimilar profiles or sequences. High coding sequence similarity and highly similar expression profiles are only weakly correlated, implying that promoter and coding regions of these gene pairs display different degrees of diversification. 相似文献
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C. J. Anderson W. T. Tay A. McGaughran K. Gordon T. K. Walsh 《Molecular ecology》2016,25(21):5296-5311
Helicoverpa armigera is a major agricultural pest that is distributed across Europe, Asia, Africa and Australasia. This species is hypothesized to have spread to the Americas 1.5 million years ago, founding a population that is at present, a distinct species, Helicoverpa zea. In 2013, H. armigera was confirmed to have re‐entered South America via Brazil and subsequently spread. The source of the recent incursion is unknown and population structure in H. armigera is poorly resolved, but a basic understanding would highlight potential biosecurity failures and determine the recent evolutionary history of region‐specific lineages. Here, we integrate several end points derived from high‐throughput sequencing to assess gene flow in H. armigera and H. zea from populations across six continents. We first assemble mitochondrial genomes to demonstrate the phylogenetic relationship of H. armigera with other Heliothine species and the lack of distinction between populations. We subsequently use de novo genotyping‐by‐sequencing and whole‐genome sequences aligned to bacterial artificial chromosomes, to assess levels of admixture. Primarily, we find that Brazilian H. armigera are derived from diverse source populations, with strong signals of gene flow from European populations, as well as prevalent signals of Asian and African ancestry. We also demonstrate a potential field‐caught hybrid between H. armigera and H. zea, and are able to provide genomic support for the presence of the H. armigera conferta subspecies in Australasia. While structure among the bulk of populations remains unresolved, we present distinctions that are pertinent to future investigations as well as to the biosecurity threat posed by H. armigera. 相似文献
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Ya‐Long Guo 《The Plant journal : for cell and molecular biology》2013,73(6):941-951
Gene family size variation is an important mechanism that shapes the natural variation for adaptation in various species. Despite its importance, the pattern of gene family size variation in green plants is still not well understood. In particular, the evolutionary pattern of genes and gene families remains unknown in the model plant Arabidopsis thaliana in the context of green plants. In this study, eight representative genomes of green plants are sampled to study gene family evolution and characterize the origination of A. thaliana genes, respectively. Four important insights gained are that: (i) the rate of gene gains and losses is about 0.001359 per gene every million years, similar to the rate in yeast, Drosophila, and mammals; (ii) some gene families evolved rapidly with extreme expansions or contractions, and 2745 gene families present in all the eight species represent the ‘core’ proteome of green plants; (iii) 70% of A. thaliana genes could be traced back to 450 million years ago; and (iv) intriguingly, A. thaliana genes with early origination are under stronger purifying selection and more conserved. In summary, the present study provides genome‐wide insights into evolutionary history and mechanisms of genes and gene families in green plants and especially in A. thaliana. 相似文献
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Sébastien Renaut 《Molecular ecology》2013,22(9):2361-2363
Variation in patterns of gene expression contributes to phenotypic diversity and can ultimately predict adaptive responses. However, in many cases, the consequences of regulatory mutations on patterns of gene expression and ultimately phenotypic differences remain elusive. A standard way to study the genetic architecture of expression variation in model systems has been to map gene expression variation to genetic loci (Fig. 1a). At the same time, in many nonmodel species, especially for long‐lived organisms, controlled crosses are not feasible. If we are to expand our understanding of the role of regulatory mutations on phenotypes, we need to develop new methodologies to study species under ecologically relevant conditions. In this issue of Molecular Ecology, Verta et al. ( 2013 ) present a new approach to analyse gene expression variation and regulatory networks in gymnosperms (Fig. 1b). They capitalized on the fact that gymnosperm seeds contain an energy storage tissue (the megagametophyte) that is directly derived from a single haploid cell (the megaspore). The authors identified over 800 genes for which expression segregated in this maternally inherited haploid tissue. Based on the observed segregation patterns, these genes (Mendelian Expression Traits) are most probably controlled by biallelic variants at a single locus. Most of these genes also belonged to different regulatory networks, except for one large group of 180 genes under the control of a putative trans‐acting factor. In addition, the approach developed here may also help to uncover the effect of rare recessive mutations, which usually remain hidden in a heterozygous state in diploid individuals. The appeal of the work by Verta et al. ( 2013 ) to study gene expression variation is in its simplicity, which circumvents several of the hurdles behind traditional expression quantitative trait locus (eQTL) studies, and could potentially be applied to a large number of species. 相似文献
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Sidney K. Pierce Nicholas E. Curtis Michael L. Middlebrooks 《Invertebrate Biology》2015,134(2):103-115
The phenomenon of the uptake, intracellular sequestration, and subsequent usage of algal chloroplasts by the digestive cells of many species of sacoglossan sea slugs, currently called kleptoplasty, has been of considerable interest since its discovery in the 1960s. While a large body of literature reported that captured chloroplasts were photosynthetically active inside slug cells and that plastid longevity in some species might be the result of the horizontal transfer of functional algal nuclear genes into the slug genome, a few recent studies have called the older results into question. Here, we have reviewed the literature and showed that while kleptoplasty occurs in many slug species and almost all derive benefit from kleptoplast photosynthesis, the slug adaptations to maintain the chloroplasts differ from species to species. These adaptations range from behavioral to molecular, including gene transfer, in a variety of combinations. 相似文献
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Bin Gao Yalin Cheng Yanhua Qu Shaoyuan Wu Shimiao Shao Yongjie Wu Per Alström Fumin Lei 《Molecular ecology》2017,26(23):6654-6665
Patterns of heterogeneous genomic differentiation have been well documented between closely related species, with some highly differentiated genomic regions (“genomic differentiation islands”) spread throughout the genome. Differential levels of gene flow are proposed to account for this pattern, as genomic differentiation islands are suggested to be resistant to gene flow. Recent studies have also suggested that genomic differentiation islands could be explained by linked selection acting on genomic regions with low recombination rates. Here, we investigate genomic differentiation and gene‐flow patterns for autosomes using RAD‐seq data between two closely related species of long‐tailed tits (Aegithalos bonvaloti and A. fuliginosus) in both allopatric and contact zone populations. The results confirm recent or ongoing gene flow between these two species. However, there is little evidence that the genomic regions that were found to be highly differentiated between the contact zone populations are resistant to gene flow, suggesting that differential levels of gene flow is not the cause of the heterogeneous genomic differentiation. Linked selection may be the cause of genomic differentiation islands between the allopatric populations with no or very limited gene flow, but this could not account for the heterogeneous genomic differentiation between the contact zone populations, which show evidence of recent or ongoing gene flow. 相似文献
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B. Brenig J. Beck C. Floren K. Bornemann‐Kolatzki I. Wiedemann S. Hennecke H. Swalve E. Schütz 《Animal genetics》2013,44(4):450-453
White Galloway cattle exhibit three different white coat colour phenotypes, that is, well marked, strongly marked and mismarked. However, mating of individuals with the preferred well or strongly marked phenotype also results in offspring with the undesired mismarked and/or even fully black coat colour. To elucidate the genetic background of the coat colour variations in White Galloway cattle, we analysed four coat colour relevant genes: mast/stem cell growth factor receptor (KIT), KIT ligand (KITLG), melanocortin 1 receptor (MC1R) and tyrosinase (TYR). Here, we show that the coat colour variations in White Galloway cattle and White Park cattle are caused by a KIT gene (chromosome 6) duplication and aberrant insertion on chromosome 29 (Cs29) as recently described for colour‐sided Belgian Blue. Homozygous (Cs29/Cs29) White Galloway cattle and White Park cattle exhibit the mismarked phenotype, whereas heterozygous (Cs29/wt29) individuals are either well or strongly marked. In contrast, fully black individuals are characterised by the wild‐type chromosome 29. As known for other cattle breeds, mutations in the MC1R gene determine the red colouring. Our data suggest that the white coat colour variations in White Galloway cattle and White Park cattle are caused by a dose‐dependent effect based on the ploidy of aberrant insertions and inheritance of the KIT gene on chromosome 29. 相似文献
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Sandra J. Simon Timothy J. Tschaplinski Jared M. LeBoldus Ken Keefover‐Ring Muhammad Azeem Jin‐Gui Chen David Macaya‐Sanz William L. MacDonald Wellington Muchero Stephen P. DiFazio 《Ecology and evolution》2020,10(11):5119-5134
Plants employ a diverse set of defense mechanisms to mediate interactions with insects and fungi. These relationships can leave lasting impacts on host plant genome structure such as rapid expansion of gene families through tandem duplication. These genomic signatures provide important clues about the complexities of plant/biotic stress interactions and evolution. We used a pseudo‐backcross hybrid family to identify quantitative trait loci (QTL) controlling associations between Populus trees and several common Populus diseases and insects. Using whole‐genome sequences from each parent, we identified candidate genes that may mediate these interactions. Candidates were partially validated using mass spectrometry to identify corresponding QTL for defensive compounds. We detected significant QTL for two interacting fungal pathogens and three insects. The QTL intervals contained candidate genes potentially involved in physical and chemical mechanisms of host–plant resistance and susceptibility. In particular, we identified adjoining QTLs for a phenolic glycoside and Phyllocolpa sawfly abundance. There was also significant enrichment of recent tandem duplications in the genomic intervals of the native parent, but not the exotic parent. Tandem gene duplication may be an important mechanism for rapid response to biotic stressors, enabling trees with long juvenile periods to reach maturity despite many coevolving biotic stressors. 相似文献
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第四纪冰期气候的反复变化对青藏高原及邻近地区植物的种群地理分布及种群遗传结构产生了巨大的影响。本研究对青藏高原东北部及其邻近地区无苞香蒲(Typha laxmannii)的15个种群148个个体的叶绿体rpl32-trnL间隔区和核基因(植物螯合肽合成酶, PS)进行测序, 共发现2个叶绿体单倍型和8个核基因单倍型。所有的单倍型被共享, 高原种群没有特有的单倍型。邻近地区种群的叶绿体遗传多样性和核基因遗传多样性分别是高原种群的4倍和2倍。高原种群的遗传分化水平明显高于邻近地区种群, 其中高原种群的遗传分化主要存在于东部种群与西部种群之间。研究结果表明, 冰期后从多个避难所回迁至高原台面和由此产生的奠基者效应造成了无苞香蒲在青藏高原东北及邻近地区目前的遗传多样性和基因谱系地理分布格局。 相似文献
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Debashish Bhattacharya Dana C. Price Cedric Bicep Eric Bapteste Mihir Sarwade Veeran D. Rajah Hwan Su Yoon 《Journal of phycology》2013,49(1):207-212
Analysis of microbial biodiversity is hampered by a lack of reference genomes from most bacteria, viruses, and algae. This necessitates either the cultivation of a restricted number of species for standard sequencing projects or the analysis of highly complex environmental DNA metagenome data. Single‐cell genomics (SCG) offers a solution to this problem by constraining the studied DNA sample to an individual cell and its associated symbionts, prey, and pathogens. We used SCG to study marine heterotrophic amoebae related to Paulinella ovalis (A. Wulff) P.W. Johnson, P.E. Hargraves & J.M. Sieburth (Rhizaria). The genus Paulinella is best known for its photosynthetic members such as P. chromatophora Lauterborn that is the only case of plastid primary endosymbiosis known outside of algae and plants. Here, we studied the phagotrophic sister taxa of P. chromatophora that are related to P. ovalis and found one SCG assembly to contain α‐cyanobacterial DNA. These cyanobacterial contigs are presumably derived from prey. We also uncovered an associated cyanophage lineage (provisionally named phage PoL_MC2). Phylogenomic analysis of the fragmented genome assembly suggested a minimum genome size of 200 Kbp for phage PoL_MC2 that encodes 179 proteins and is most closely related to Synechococcus phage S‐SM2. For this phage, gene network analysis demonstrates a highly modular genome structure typical of other cyanophages. Our work demonstrates that SCG is a powerful approach for discovering algal and protist biodiversity and for elucidating biotic interactions in natural samples. 相似文献
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Fyodor A. Kondrashov 《Proceedings. Biological sciences / The Royal Society》2012,279(1749):5048-5057
A subject of extensive study in evolutionary theory has been the issue of how neutral, redundant copies can be maintained in the genome for long periods of time. Concurrently, examples of adaptive gene duplications to various environmental conditions in different species have been described. At this point, it is too early to tell whether or not a substantial fraction of gene copies have initially achieved fixation by positive selection for increased dosage. Nevertheless, enough examples have accumulated in the literature that such a possibility should be considered. Here, I review the recent examples of adaptive gene duplications and make an attempt to draw generalizations on what types of genes may be particularly prone to be selected for under certain environmental conditions. The identification of copy-number variation in ecological field studies of species adapting to stressful or novel environmental conditions may improve our understanding of gene duplications as a mechanism of adaptation and its relevance to the long-term persistence of gene duplications. 相似文献