scholarly journals Tripsacum de novo transcriptome assemblies reveal parallel gene evolution with maize after ancient polyploidy

2018 ◽  
Author(s):  
Christine M. Gault ◽  
Karl A. Kremling ◽  
Edward S. Buckler
Keyword(s):  
Gene Expression ◽  
Gene Loss ◽  
Genome Duplication ◽  
De Novo ◽  
Gc Content ◽  
Purifying Selection ◽  
Duplicate Gene ◽  
Duplication Event ◽  
High Quality ◽  
Genome Duplication Event

AbstractPlant genomes reduce in size following a whole genome duplication event, and one gene in a duplicate gene pair can lose function in absence of selective pressure to maintain duplicate gene copies. Maize and its sister genus, Tripsacum, share a genome duplication event that occurred 5 to 26 million years ago. Because few genomic resources for Tripsacum exist, it is unknown whether Tripsacum grasses and maize have maintained a similar set of genes under purifying selection. Here we present high quality de novo transcriptome assemblies for two species: Tripsacum dactyloides and Tripsacum floridanum. Genes with experimental protein evidence in maize were good candidates for genes under purifying selection in both genera because pseudogenes by definition do not produce protein. We tested whether 15,160 maize genes with protein evidence are resisting gene loss and whether their Tripsacum homologs are also resisting gene loss. Protein-encoding maize transcripts and their Tripsacum homologs have higher GC content, higher gene expression levels, and more conserved expression levels than putatively untranslated maize transcripts and their Tripsacum homologs. These results indicate that gene loss is occurring in a similar fashion in both genera after a shared ancient polyploidy event. The Tripsacum transcriptome assemblies provide a high quality genomic resource that can provide insight into the evolution of maize, an highly valuable crop worldwide.Core ideasMaize genes with protein evidence have higher expression and GC contentTripsacum homologs of maize genes exhibit the same trends as in maizeMaize proteome genes have more highly correlated gene expression with TripsacumExpression dominance for homeologs occurs similarly between maize and TripsacumA similar set of genes may be decaying into pseudogenes in maize and Tripsacum

scholarly journals Limited role of differential fractionation in genome content variation and function in maize (Zea mays L.) inbred lines

2017 ◽  
Author(s):  
Alex B. Brohammer ◽  
Thomas JY. Kono ◽  
Nathan M. Springer ◽  
Suzanne E. McGaugh ◽  
Candice N. Hirsch
Keyword(s):  
Large Scale ◽  
De Novo ◽  
Duplicate Gene ◽  
Duplication Event ◽  
Inbred Lines ◽  
Whole Genome ◽  
Ancestral State ◽  
Genome Duplication Event ◽  
Number Variation ◽  
And Function

SUMMARYMaize is a diverse paleotetraploid species with widespread presence/absence variation and copy number variation. One mechanism through which presence/absence variation can arise is differential fractionation. Fractionation refers to the loss of duplicate gene pairs from one of the maize subgenomes during diploidization and differential fractionation refers to non-shared gene loss events between individuals. We investigated the prevalence of presence/absence variation resulting from differential fractionation in the syntenic portion of the genome using two whole genome de novo assemblies of the inbred lines B73 and PH207. Between these two genomes, syntenic genes were highly conserved with less than 1% of syntenic genes being subject to differential fractionation. The few variable syntenic genes that were identified are unlikely to contribute to functional phenotypic variation, as there is a significant depletion of these genes in annotated gene sets. In further comparisons of 60 diverse inbred lines, non-syntenic genes were six times more likely to be variable compared to syntenic genes, suggesting that comparisons among additional genome assemblies are not likely to result in the discovery of large-scale presence/absence variation among syntenic genes.SIGNIFICANCE STATEMENTThere is a large amount of presence/absence variation for gene content in maize. One mechanism that has been hypothesized to contribute to this variation is differential fractionation between individuals following the maize whole genome duplication event. Using comparative genomics, with sorghum and rice representing the ancestral state, we observed little evidence of differential fractionation among elite inbred lines and the few differentially fractionated genes identified did not appear to confer functional significance.

scholarly journals A chromosome-level genome of the spider Trichonephila antipodiana reveals the genetic basis of its polyphagy and evidence of an ancient whole-genome duplication event

GigaScience ◽  
2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Zheng Fan ◽  
Tao Yuan ◽  
Piao Liu ◽  
Lu-Yu Wang ◽  
Jian-Feng Jin ◽  
...  
Keyword(s):  
Whole Genome Duplication ◽  
Large Scale ◽  
Hox Genes ◽  
Genome Duplication ◽  
Duplication Event ◽  
Whole Genome ◽  
High Quality ◽  
Genome Duplication Event ◽  
Whole Genome Duplication Event ◽  
Chromosome Level

Abstract Background The spider Trichonephila antipodiana (Araneidae), commonly known as the batik golden web spider, preys on arthropods with body sizes ranging from ∼2 mm in length to insects larger than itself (>20‒50 mm), indicating its polyphagy and strong dietary detoxification abilities. Although it has been reported that an ancient whole-genome duplication event occurred in spiders, lack of a high-quality genome has limited characterization of this event. Results We present a chromosome-level T. antipodiana genome constructed on the basis of PacBio and Hi-C sequencing. The assembled genome is 2.29 Gb in size with a scaffold N50 of 172.89 Mb. Hi-C scaffolding assigned 98.5% of the bases to 13 pseudo-chromosomes, and BUSCO completeness analysis revealed that the assembly included 94.8% of the complete arthropod universal single-copy orthologs (n = 1,066). Repetitive elements account for 59.21% of the genome. We predicted 19,001 protein-coding genes, of which 96.78% were supported by transcriptome-based evidence and 96.32% matched protein records in the UniProt database. The genome also shows substantial expansions in several detoxification-associated gene families, including cytochrome P450 mono-oxygenases, carboxyl/cholinesterases, glutathione-S-transferases, and ATP-binding cassette transporters, reflecting the possible genomic basis of polyphagy. Further analysis of the T. antipodiana genome architecture reveals an ancient whole-genome duplication event, based on 2 lines of evidence: (i) large-scale duplications from inter-chromosome synteny analysis and (ii) duplicated clusters of Hox genes. Conclusions The high-quality T. antipodiana genome represents a valuable resource for spider research and provides insights into this species’ adaptation to the environment.

scholarly journals The ancient Salicoid genome duplication event: A platform for reconstruction of de Novo gene evolution in Populus trichocarpa

2021 ◽  
Author(s):  
Timothy B Yates ◽  
Kai Feng ◽  
Jin Zhang ◽  
Vasanth Singan ◽  
Sara S Jawdy ◽  
...  
Keyword(s):  
Genome Duplication ◽  
De Novo ◽  
Gene Evolution ◽  
Populus Trichocarpa ◽  
Duplication Event ◽  
Functional Enrichment ◽  
Orphan Genes ◽  
Genome Duplication Event ◽  
Orphan Gene ◽  
De Novo Gene

Abstract Orphan genes are characteristic genomic features that have no detectable homology to genes in any other species and represent an important attribute of genome evolution as sources of novel genetic functions. Here, we identified 445 genes specific to Populus trichocarpa. Of these, we performed deeper reconstruction of 13 orphan genes to provide evidence of de novo gene evolution. Populus and its sister genera Salix are particularly well suited for the study of orphan gene evolution because of the Salicoid whole-genome duplication event (WGD) which resulted in highly syntenic sister chromosomal segments across the Salicaceae. We leveraged this genomic feature to reconstruct de novo gene evolution from inter-genera, inter-species, and intra-genomic perspectives by comparing the syntenic regions within the P. trichocarpa reference, then P. deltoides, and finally Salix purpurea. Furthermore, we demonstrated that 86.5% of the putative orphan genes had evidence of transcription. Additionally, we also utilized the Populus genome-wide association mapping panel (GWAS), a collection of 1,084 undomesticated P. trichocarpa genotypes to further determine putative regulatory networks of orphan genes using expression quantitative trait loci (eQTL) mapping. Functional enrichment of these eQTL subnetworks identified common biological themes associated with orphan genes such as response to stress and defense response. We also identify a putative cis-element for a de novo gene and leverage conserved synteny to describe evolution of a putative transcription factor binding site. Overall, 45% of orphan genes were captured in trans-eQTL networks.

scholarly journals Global assessment of organ specific basal gene expression over a diurnal cycle with analyses of gene copies exhibiting cyclic expression patterns

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Yuan Lu ◽  
Mikki Boswell ◽  
William Boswell ◽  
Raquel Ybanez Salinas ◽  
Markita Savage ◽  
...  
Keyword(s):  
Gene Expression ◽  
Expression Pattern ◽  
Genome Duplication ◽  
Functional Divergence ◽  
Expression Patterns ◽  
Duplication Event ◽  
Global Scale ◽  
Genome Duplication Event ◽  
Gene Copies ◽  
Cyclic Expression

Abstract Background Studying functional divergences between paralogs that originated from genome duplication is a significant topic in investigating molecular evolution. Genes that exhibit basal level cyclic expression patterns including circadian and light responsive genes are important physiological regulators. Temporal shifts in basal gene expression patterns are important factors to be considered when studying genetic functions. However, adequate efforts have not been applied to studying basal gene expression variation on a global scale to establish transcriptional activity baselines for each organ. Furthermore, the investigation of cyclic expression pattern comparisons between genome duplication created paralogs, and potential functional divergence between them has been neglected. To address these questions, we utilized a teleost fish species, Xiphophorus maculatus, and profiled gene expression within 9 organs at 3-h intervals throughout a 24-h diurnal period. Results Our results showed 1.3–21.9% of genes in different organs exhibited cyclic expression patterns, with eye showing the highest fraction of cycling genes while gonads yielded the lowest. A majority of the duplicated gene pairs exhibited divergences in their basal level expression patterns wherein only one paralog exhibited an oscillating expression pattern, or both paralogs exhibit oscillating expression patterns, but each gene duplicate showed a different peak expression time, and/or in different organs. Conclusions These observations suggest cyclic genes experienced significant sub-, neo-, or non-functionalization following the teleost genome duplication event. In addition, we developed a customized, web-accessible, gene expression browser to facilitate data mining and data visualization for the scientific community.

scholarly journals High-quality de novo assembly of the Eucommia ulmoides haploid genome provides new insights into evolution and rubber biosynthesis

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Yun Li ◽  
Hairong Wei ◽  
Jun Yang ◽  
Kang Du ◽  
Jiang Li ◽  
...  
Keyword(s):  
De Novo ◽  
Mevalonate Pathway ◽  
Genome Structure ◽  
Duplication Event ◽  
Eucommia Ulmoides ◽  
Long Terminal Repeats ◽  
High Quality ◽  
Genome Duplication Event ◽  
Protein Coding ◽  
Rubber Biosynthesis

Abstract We report the acquisition of a high-quality haploid chromosome-scale genome assembly for the first time in a tree species, Eucommia ulmoides, which is known for its rubber biosynthesis and medicinal applications. The assembly was obtained by applying PacBio and Hi–C technologies to a haploid that we specifically generated. Compared to the initial genome release, this one has significantly improved assembly quality. The scaffold N50 (53.15 MB) increased 28-fold, and the repetitive sequence content (520 Mb) increased by 158.24 Mb, whereas the number of gaps decreased from 104,772 to 128. A total of 92.87% of the 26,001 predicted protein-coding genes identified with multiple strategies were anchored to the 17 chromosomes. A new whole-genome duplication event was superimposed on the earlier γ paleohexaploidization event, and the expansion of long terminal repeats contributed greatly to the evolution of the genome. The more primitive rubber biosynthesis of this species, as opposed to that in Hevea brasiliensis, relies on the methylerythritol-phosphate pathway rather than the mevalonate pathway to synthesize isoprenyl diphosphate, as the MEP pathway operates predominantly in trans-polyisoprene-containing leaves and central peels. Chlorogenic acid biosynthesis pathway enzymes were preferentially expressed in leaves rather than in bark. This assembly with higher sequence contiguity can foster not only studies on genome structure and evolution, gene mapping, epigenetic analysis and functional genomics but also efforts to improve E. ulmoides for industrial and medical uses through genetic engineering.

scholarly journals Patterns of gene-body-methylation conservation and its divergent association with gene expression in Pigeonpea and Soybean

2020 ◽  
Author(s):  
Alim Junaid ◽  
N.K. Singh ◽  
Kishor Gaikwad
Keyword(s):  
Gene Expression ◽  
Expression Patterns ◽  
Crop Improvement ◽  
Duplicate Gene ◽  
Duplication Event ◽  
Gene Body ◽  
Gene Body Methylation ◽  
Genome Duplication Event ◽  
Slow Evolution ◽  
The Impact

AbstractPigeonpea and Soybean are closely related agronomically important legumes that diverged ∼23 million years ago followed by a whole genome duplication event in Soybean. However, the impact of divergence on their epigenomes is not known. Comparative epigenomics is a powerful tool to understand shaping of epigenomes and its functional consequences during evolution. In this study, we investigated the conservation and divergence of Gene body methylation (GbM) and gene-expression patterns between the two species. We compared their genome-wide DNA methylation landscape at single-base resolution and studied the influence of GbM on duplicate gene retention. Our results indicate that during the divergence of Pigeonpea and Soybean, the effects of methylation on gene expression evolved in a heterogeneous manner. GbM features-slow evolution rate and increased length remained conserved in Pigeonpea and Soybean. We also found that contrary to high CG-methylation conservation, non-CG methylated genes remained diverged during evolution due to transposons insertion in adjacent sequences. The methylation differences in paralogs were associated with expression divergence. Notably, we found that variably methylated marks are less likely to target evolutionary conserved sequences. Finally, our findings identify conservation of nitrogen-related genes during evolution, which are promising candidates for epi-alleles for crop improvement.

scholarly journals Gene-interleaving patterns of synteny in the Saccharomyces cerevisiae genome: are they proof of an ancient genome duplication event?

2007 ◽  
Vol 2 (1) ◽  
pp. 23 ◽  
Author(s):  
Nicolas Martin ◽  
Elizabeth A Ruedi ◽  
Richard LeDuc ◽  
Feng-Jie Sun ◽  
Gustavo Caetano-Anollés
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Genome Duplication ◽  
Duplication Event ◽  
Genome Duplication Event

scholarly journals Facile, High Quality Sequencing of Bacterial Genomes from Small Amounts of DNA

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Momchilo Vuyisich ◽  
Ayesha Arefin ◽  
Karen Davenport ◽  
Shihai Feng ◽  
Cheryl Gleasner ◽  
...  
Keyword(s):  
Genomic Dna ◽  
De Novo ◽  
Gc Content ◽  
Library Preparation ◽  
Sequencing Data ◽  
Bacterial Genomes ◽  
Dna Amount ◽  
High Quality ◽  
Preparation Methods

Sequencing bacterial genomes has traditionally required large amounts of genomic DNA (~1 μg). There have been few studies to determine the effects of the input DNA amount or library preparation method on the quality of sequencing data. Several new commercially available library preparation methods enable shotgun sequencing from as little as 1 ng of input DNA. In this study, we evaluated the NEBNext Ultra library preparation reagents for sequencing bacterial genomes. We have evaluated the utility of NEBNext Ultra for resequencing andde novoassembly of four bacterial genomes and compared its performance with the TruSeq library preparation kit. The NEBNext Ultra reagents enable high quality resequencing andde novoassembly of a variety of bacterial genomes when using 100 ng of input genomic DNA. For the two most challenging genomes (Burkholderiaspp.), which have the highest GC content and are the longest, we also show that the quality of both resequencing andde novoassembly is not decreased when only 10 ng of input genomic DNA is used.

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