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1.
Front Plant Sci ; 15: 1350281, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38736448

RESUMO

Fungal diseases, caused mainly by Bipolaris spp., are past and current threats to Northern Wild Rice (NWR) grain production and germplasm preservation in both natural and cultivated settings. Genetic resistance against the pathogen is scarce. Toward expanding our understanding of the global gene communications of NWR and Bipolaris oryzae interaction, we designed an RNA sequencing study encompassing the first 12 h and 48 h of their encounter. NWR activated numerous plant recognition receptors after pathogen infection, followed by active transcriptional reprogramming of signaling mechanisms driven by Ca2+ and its sensors, mitogen-activated protein kinase cascades, activation of an oxidative burst, and phytohormone signaling-bound mechanisms. Several transcription factors associated with plant defense were found to be expressed. Importantly, evidence of diterpenoid phytoalexins, especially phytocassane biosynthesis, among expression of other defense genes was found. In B. oryzae, predicted genes associated with pathogenicity including secreted effectors that could target plant defense mechanisms were expressed. This study uncovered the early molecular communication between the NWR-B. oryzae pathosystem, which could guide selection for allele-specific genes to boost NWR defenses, and overall aid in the development of more efficient selection methods in NWR breeding through the use of the most virulent fungal isolates.

2.
Front Physiol ; 14: 1293264, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38074316

RESUMO

Thermal stress alters the transcriptome and subsequent tissue physiology of poultry; thus, it can negatively impact poultry production through reduced meat quality, egg production, and health and wellbeing. The modulation of gene expression is critical to embryonic development and cell proliferation, and growing evidence suggests the role of non-coding RNAs (RNA:RNA interaction) in response to thermal stress in animals. MicroRNAs (miRNAs) comprise a class of small regulatory RNAs that modulate gene expression through posttranscriptional interactions and regulate mRNAs, potentially altering numerous cellular processes. This study was designed to identify and characterize the differential expression of miRNAs in satellite cells (SCs) from the turkey pectoralis major muscle and predict important miRNA:mRNA interactions in these developing SCs under a thermal challenge. Small RNA sequencing was performed on RNA libraries prepared from SCs cultured from 1-week-old male Nicholas commercial turkeys (NCTs) and non-selected Randombred Control Line 2 turkeys during proliferation and differentiation at the control temperature (38°C) or under a thermal challenge (33°C or 43°C). A total of 353 miRNAs (161 known and 192 novel) were detected across the sequenced libraries. Expression analysis found fewer differentially expressed miRNAs in the SCs of NCT birds, suggesting that the miRNA response to heat stress has been altered in birds selected for their modern commercial growth traits. Differentially expressed miRNAs, including those with described roles in muscle development, were detected both among temperature treatments and between genetic lines. A prominent differential expression of miR-206 was found in proliferating turkey SCs with a significant response to thermal challenges in both lines. In differentiating SCs, isoforms of miR-1 had significant differential responses, with the expression of miR-206 being mainly affected only by cold treatment. Target gene predictions and Gene Ontology analysis suggest that the differential expression of miRNAs during thermal stress could significantly affect cellular proliferation and differentiation.

3.
J Hered ; 113(5): 538-551, 2022 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-35922036

RESUMO

Combining genetic and ecological measures of differentiation can provide compelling evidence for ecological and genetic divergence among lineages. The rough-footed mud turtle, Kinosternon hirtipes, is distributed from the Trans-Pecos region of Texas to the highlands of Central Mexico and contains 6 described subspecies, 5 of which are extant. We use ddRAD sequencing and species distribution models to assess levels of ecological and genetic differentiation among these subspecies. We also predict changes in climatically suitable habitat under different climate change scenarios and assess levels of genetic diversity and inbreeding within each lineage. Our results show that there is strong genetic and ecological differentiation among multiple lineages within K. hirtipes, and that this differentiation appears to be the result of vicariance associated with the Trans-Mexican Volcanic Belt. We propose changes to subspecies designations to more accurately reflect the evolutionary relationships among populations and assess threats to each subspecies.


Assuntos
Tartarugas , Animais , Tartarugas/genética , Ecossistema , Mudança Climática , Evolução Biológica , Genômica
4.
G3 (Bethesda) ; 12(2)2022 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-34897429

RESUMO

The zebra mussel, Dreissena polymorpha, continues to spread from its native range in Eurasia to Europe and North America, causing billions of dollars in damage and dramatically altering invaded aquatic ecosystems. Despite these impacts, there are few genomic resources for Dreissena or related bivalves. Although the D. polymorpha genome is highly repetitive, we have used a combination of long-read sequencing and Hi-C-based scaffolding to generate a high-quality chromosome-scale genome assembly. Through comparative analysis and transcriptomics experiments, we have gained insights into processes that likely control the invasive success of zebra mussels, including shell formation, synthesis of byssal threads, and thermal tolerance. We identified multiple intact steamer-like elements, a retrotransposon that has been linked to transmissible cancer in marine clams. We also found that D. polymorpha have an unusual 67 kb mitochondrial genome containing numerous tandem repeats, making it the largest observed in Eumetazoa. Together these findings create a rich resource for invasive species research and control efforts.


Assuntos
Dreissena , Animais , Dreissena/genética , Ecossistema , Genoma , Genômica , Espécies Introduzidas
5.
Plant J ; 107(6): 1802-1818, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34310794

RESUMO

Zizania palustris L. (northern wild rice, NWR) is an aquatic grass native to North America that is notable for its nutritious grain. This is an important species with ecological, cultural and agricultural significance, specifically in the Great Lakes region of the USA. Using flow cytometry, we first estimated the NWR genome size to be 1.8 Gb. Using long- and short-range sequencing, Hi-C scaffolding and RNA-seq data from eight tissues, we generated an annotated whole-genome de novo assembly of NWR. The assembly was 1.29 Gb in length, highly repetitive (approx. 76.0%) and contained 46 421 putative protein-coding genes. The expansion of retrotransposons within the genome and a whole-genome duplication (WGD) after the Zizania-Oryza speciation event have both led to an increase in the genome size of NWR in comparison with Oryza sativa L. and Zizania latifolia. Both events depict a genome rapidly undergoing change over a short evolutionary time. Comparative analyses revealed the conservation of large syntenic blocks between NWR and O. sativa, which were used to identify putative seed-shattering genes. Estimates of divergence times revealed that the Zizania genus diverged from Oryza approximately 26-30 million years ago (26-30 MYA), whereas NWR and Z. latifolia diverged from one another approximately 6-8 MYA. Comparative genomics confirmed evidence of a WGD in the Zizania genus and provided support that the event occurred prior to the NWR-Z. latifolia speciation event. This genome assembly and annotation provides a valuable resource for comparative genomics in the Oryzeae tribe and provides an important resource for future conservation and breeding efforts of NWR.


Assuntos
Genoma de Planta , Oryza/genética , Poaceae/genética , Evolução Molecular , Citometria de Fluxo , Duplicação Gênica , Tamanho do Genoma , Genômica , Minnesota , Anotação de Sequência Molecular , Filogenia , Melhoramento Vegetal , Sequências Repetitivas de Ácido Nucleico , Transcriptoma
6.
Sci Rep ; 10(1): 11290, 2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32647312

RESUMO

Smoking-related lung tumors are characterized by profound epigenetic changes including scrambled patterns of DNA methylation, deregulated histone acetylation, altered gene expression levels, distorted microRNA profiles, and a global loss of cytosine hydroxymethylation marks. Here, we employed an enhanced version of bisulfite sequencing (RRBS/oxRRBS) followed by next generation sequencing to separately map DNA epigenetic marks 5-methyl-dC and 5-hydroxymethyl-dC in genomic DNA isolated from lungs of A/J mice exposed whole-body to environmental cigarette smoke for 10 weeks. Exposure to cigarette smoke significantly affected the patterns of cytosine methylation and hydroxymethylation in the lungs. Differentially hydroxymethylated regions were associated with inflammatory response/disease, organismal injury, and respiratory diseases and were involved in regulation of cellular development, function, growth, and proliferation. To identify epigenetic changes in the lung associated with exposure to tobacco carcinogens and inflammation, A/J mice were intranasally treated with the tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), the inflammatory agent lipopolysaccharide (LPS), or both. NNK alone caused minimal epigenetic alterations, while exposure either to LPS or NNK/LPS in combination led to increased levels of global cytosine methylation and formylation, reduced cytosine hydroxymethylation, decreased histone acetylation, and altered expression levels of multiple genes. Our results suggest that inflammatory processes are responsible for epigenetic changes contributing to lung cancer development.


Assuntos
Epigênese Genética , Exposição por Inalação , Neoplasias Pulmonares/genética , Pulmão/efeitos dos fármacos , Fumaça/efeitos adversos , Animais , Carcinógenos/metabolismo , Proliferação de Células , Cromatografia Líquida de Alta Pressão , Ilhas de CpG , Citosina/química , DNA/metabolismo , Metilação de DNA , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Histonas/química , Histonas/metabolismo , Inflamação , Camundongos , Camundongos Endogâmicos , Nitrosaminas/metabolismo , Fumar , Sulfitos/farmacologia , Nicotiana , Produtos do Tabaco
7.
Neuropsychopharmacology ; 45(11): 1781-1792, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32079024

RESUMO

Drug-evoked adaptations in the mesolimbic dopamine system are postulated to drive opioid abuse and addiction. These adaptations vary in magnitude and direction following different patterns of opioid exposure, but few studies have systematically manipulated the pattern of opioid administration while measuring neurobiological and behavioral impact. We exposed male and female mice to morphine for one week, with administration patterns that were either intermittent (daily injections) or continuous (osmotic minipump infusion). We then interrupted continuous morphine exposure with either naloxone-precipitated or spontaneous withdrawal. Continuous morphine exposure caused tolerance to the psychomotor-activating effects of morphine, whereas both intermittent and interrupted morphine exposure caused long-lasting psychomotor sensitization. Given links between locomotor sensitization and mesolimbic dopamine signaling, we used fiber photometry and a genetically encoded dopamine sensor to conduct longitudinal measurements of dopamine dynamics in the nucleus accumbens. Locomotor sensitization caused by interrupted morphine exposure was accompanied by enhanced dopamine signaling in the nucleus accumbens. To further assess downstream consequences on striatal gene expression, we used next-generation RNA sequencing to perform genome-wide transcriptional profiling in the nucleus accumbens and dorsal striatum. The interruption of continuous morphine exposure exacerbated drug-evoked transcriptional changes in both nucleus accumbens and dorsal striatum, dramatically increasing differential gene expression and engaging unique signaling pathways. Our study indicates that opioid-evoked adaptations in brain function and behavior are critically dependent on the pattern of drug administration, and exacerbated by interruption of continuous exposure. Maintaining continuity of chronic opioid administration may, therefore, represent a strategy to minimize iatrogenic effects on brain reward circuits.


Assuntos
Analgésicos Opioides , Preparações Farmacêuticas , Animais , Encéfalo , Dopamina , Feminino , Masculino , Camundongos , Morfina , Núcleo Accumbens
8.
Ecol Evol ; 10(2): 940-951, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32015856

RESUMO

As the environment changes, so too must plant communities and populations if they are to persist. Life-history transitions and their timing are often the traits that are most responsive to changing environmental conditions. To compare the contributions of plasticity and natural selective response to variation in germination and flowering phenology, we performed a quantitative genetic study of phenotypic selection on Chamaecrista fasciculata (Fabaceae) across two consecutive years in a restored tallgrass prairie. The earliest dates of germination and flowering were recorded for two parental cohorts and one progeny cohort in an experimental garden. Environmental differences between years were the largest contributors to phenological variation in this population. In addition, there was substantial heritability for flowering time and statistically significant selection for advancement of flowering. Comparison between a progeny cohort and its preselection parental cohort indicated a change in mean flowering time consistent with the direction of selection. Selection on germination time was weaker than that on flowering time, while environmental effects on germination time were stronger. The response to selection on flowering time was detectable when accounting for the effect of the environment on phenotypic differences, highlighting the importance of controlling for year-to-year environmental variation in quantitative genetic studies.

9.
Int J Mol Sci ; 22(1)2020 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-33396408

RESUMO

Epigenetic dysregulation is hypothesized to play a role in the observed association between inflammatory bowel disease (IBD) and colon tumor development. In the present work, DNA methylome, hydroxymethylome, and transcriptome analyses were conducted in proximal colon tissues harvested from the Helicobacter hepaticus (H. hepaticus)-infected murine model of IBD. Reduced representation bisulfite sequencing (RRBS) and oxidative RRBS (oxRRBS) analyses identified 1606 differentially methylated regions (DMR) and 3011 differentially hydroxymethylated regions (DhMR). These DMR/DhMR overlapped with genes that are associated with gastrointestinal disease, inflammatory disease, and cancer. RNA-seq revealed pronounced expression changes of a number of genes associated with inflammation and cancer. Several genes including Duox2, Tgm2, Cdhr5, and Hk2 exhibited changes in both DNA methylation/hydroxymethylation and gene expression levels. Overall, our results suggest that chronic inflammation triggers changes in methylation and hydroxymethylation patterns in the genome, altering the expression of key tumorigenesis genes and potentially contributing to the initiation of colorectal cancer.


Assuntos
Metilação de DNA , Proteínas de Ligação a DNA/fisiologia , Regulação da Expressão Gênica , Hiperplasia/patologia , Doenças Inflamatórias Intestinais/complicações , Interleucina-10/fisiologia , Transcriptoma , Animais , Modelos Animais de Doenças , Epigenômica , Feminino , Hiperplasia/etiologia , Hiperplasia/metabolismo , Masculino , Camundongos , Camundongos Knockout , Regiões Promotoras Genéticas
10.
PLoS One ; 14(12): e0227079, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31877180

RESUMO

Since the mid-20th century, crop breeding has driven unprecedented yield gains. Breeders generally select for broadly- and reliably-performing varieties that display little genotype-by-environment interaction (GxE). In contrast, ecological theory predicts that across environments that vary spatially or temporally, the most productive population will be a mixture of narrowly adapted specialists. We quantified patterns of broad and narrow adaptation in modern, commercial maize (Zea mays L.) hybrids planted across 216 site-years, from 1999-2018, for the University of Illinois yield trials. We found that location was the dominant source of yield variation (44.5%), and yearly weather was the smallest (1.7%), which suggested a benefit for reliable performance in narrow biophysical environments. Varieties displayed a large "home field advantage" when growing in the location of best performance relative to other varieties. Home field advantage accounted for 19% of GxE and provided a yield increase of 1.01 ± 0.04 Mg ∙ ha-1 (7.6% relative to mean yield), yet was both smaller than predicted by a null model and unchanged across time. This counterfactual suggests that commercial breeding programs have missed an opportunity to further increase yields by leveraging local adaptation. Public breeding programs may pursue this opportunity by releasing specialist varieties that perform reliably in narrow environments. As seed sources are increasingly privatized and consolidated, this alternate strategy may compliment private breeding to support global food security.


Assuntos
Melhoramento Vegetal/métodos , Zea mays/genética , Interação Gene-Ambiente , Genótipo , Hibridização Genética , Fenótipo , Zea mays/crescimento & desenvolvimento
11.
Genetics ; 213(4): 1531-1544, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31653677

RESUMO

Targeted identification and purging of deleterious genetic variants has been proposed as a novel approach to animal and plant breeding. This strategy is motivated, in part, by the observation that demographic events and strong selection associated with cultivated species pose a "cost of domestication." This includes an increase in the proportion of genetic variants that are likely to reduce fitness. Recent advances in DNA resequencing and sequence constraint-based approaches to predict the functional impact of a mutation permit the identification of putatively deleterious SNPs (dSNPs) on a genome-wide scale. Using exome capture resequencing of 21 barley lines, we identified 3855 dSNPs among 497,754 total SNPs. We generated whole-genome resequencing data of Hordeum murinum ssp. glaucum as a phylogenetic outgroup to polarize SNPs as ancestral vs. derived. We also observed a higher proportion of dSNPs per synonymous SNPs (sSNPs) in low-recombination regions of the genome. Using 5215 progeny from a genomic prediction experiment, we examined the fate of dSNPs over three breeding cycles. Adjusting for initial frequency, derived alleles at dSNPs reduced in frequency or were lost more often than other classes of SNPs. The highest-yielding lines in the experiment, as chosen by standard genomic prediction approaches, carried fewer homozygous dSNPs than randomly sampled lines from the same progeny cycle. In the final cycle of the experiment, progeny selected by genomic prediction had a mean of 5.6% fewer homozygous dSNPs relative to randomly chosen progeny from the same cycle.


Assuntos
Variação Genética , Genômica , Hordeum/genética , Variação Biológica da População , Códon/genética , Exoma/genética , Frequência do Gene/genética , Genética Populacional , Genótipo , Homozigoto , Melhoramento Vegetal , Polimorfismo de Nucleotídeo Único/genética , Análise de Sequência de DNA
12.
Chem Res Toxicol ; 32(5): 831-839, 2019 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-30942577

RESUMO

Lipopolysaccharide (LPS) is a bacterial endotoxin present in cigarette smoke. LPS is known to induce inflammation and to increase the size and the multiplicity of lung tumors induced by tobacco-specific nitrosamines. However, the means by which LPS contributes to pulmonary carcinogenesis are not known. One possible mechanism includes LPS-mediated epigenetic deregulation, which leads to aberrant expression of genes involved in DNA repair, tumor suppression, cell cycle progression, and cell growth. In the present work, epigenetic effects of LPS were examined in alveolar type II lung cells of A/J mice. Type II cells were selected because they serve as progenitors of lung adenocarcinomas in smoking induced lung cancer. A/J mice were intranasally treated with LPS, followed by isolation of alveolar type II cells from the lung using cell panning. Global levels of DNA methylation and histone acetylation were quantified by mass spectrometry, while genome-wide transcriptomic changes were characterized by RNA-Seq. LPS treatment was associated with epigenetic changes including decreased cytosine formylation and reduced histone H3K14 and H3K23 acetylation, as well as altered expression levels of genes involved in cell adhesion, inflammation, immune response, and epigenetic regulation. These results suggest that exposure to inflammatory agents in cigarette smoke leads to early epigenetic changes in the lung, which may collaborate with genetic changes to drive the development of lung cancer.


Assuntos
Células Epiteliais Alveolares/efeitos dos fármacos , Lipopolissacarídeos/toxicidade , Acetilação , Células Epiteliais Alveolares/citologia , Células Epiteliais Alveolares/metabolismo , Animais , Células Cultivadas , Cromatografia Líquida de Alta Pressão , DNA/análise , DNA/isolamento & purificação , Metilação de DNA , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Histonas/metabolismo , Espectrometria de Massas , Camundongos
13.
BMC Plant Biol ; 19(1): 45, 2019 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-30704393

RESUMO

BACKGROUND: Maize stover is an important source of crop residues and a promising sustainable energy source in the United States. Stalk is the main component of stover, representing about half of stover dry weight. Characterization of genetic determinants of stalk traits provide a foundation to optimize maize stover as a biofuel feedstock. We investigated maize natural genetic variation in genome-wide association studies (GWAS) to detect candidate genes associated with traits related to stalk biomass (stalk diameter and plant height) and stalk anatomy (rind thickness, vascular bundle density and area). RESULTS: Using a panel of 942 diverse inbred lines, 899,784 RNA-Seq derived single nucleotide polymorphism (SNP) markers were identified. Stalk traits were measured on 800 members of the panel in replicated field trials across years. GWAS revealed 16 candidate genes associated with four stalk traits. Most of the detected candidate genes were involved in fundamental cellular functions, such as regulation of gene expression and cell cycle progression. Two of the regulatory genes (Zmm22 and an ortholog of Fpa) that were associated with plant height were previously shown to be involved in regulating the vegetative to floral transition. The association of Zmm22 with plant height was confirmed using a transgenic approach. Transgenic lines with increased expression of Zmm22 showed a significant decrease in plant height as well as tassel branch number, indicating a pleiotropic effect of Zmm22. CONCLUSION: Substantial heritable variation was observed in the association panel for stalk traits, indicating a large potential for improving useful stalk traits in breeding programs. Genome-wide association analyses detected several candidate genes associated with multiple traits, suggesting common regulatory elements underlie various stalk traits. Results of this study provide insights into the genetic control of maize stalk anatomy and biomass.


Assuntos
Caules de Planta/anatomia & histologia , Característica Quantitativa Herdável , Zea mays/genética , Biomassa , Regulação da Expressão Gênica de Plantas/genética , Genes de Plantas/genética , Genes de Plantas/fisiologia , Estudo de Associação Genômica Ampla , Caules de Planta/genética , Caules de Planta/crescimento & desenvolvimento , Polimorfismo de Nucleotídeo Único/genética , Zea mays/anatomia & histologia , Zea mays/crescimento & desenvolvimento
14.
Mol Ecol Resour ; 19(2): 456-464, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30447171

RESUMO

RNA sequencing is a popular next-generation sequencing technique for assaying genome-wide gene expression profiles. Nonetheless, it is susceptible to biases that are introduced by sample handling prior gene expression measurements. Two of the most common methods for preserving samples in both field-based and laboratory conditions are submersion in RNAlater and flash freezing in liquid nitrogen. Flash freezing in liquid nitrogen can be impractical, particularly for field collections. RNAlater is a solution for stabilizing tissue for longer-term storage as it rapidly permeates tissue to protect cellular RNA. In this study, we assessed genome-wide expression patterns in 30-day-old fry collected from the same brood at the same time point that were flash-frozen in liquid nitrogen and stored at -80°C or submerged and stored in RNAlater at room temperature, simulating conditions of fieldwork. We show that sample storage is a significant factor influencing observed differential gene expression. In particular, genes with elevated GC content exhibit higher observed expression levels in liquid nitrogen flash-freezing relative to RNAlater storage. Further, genes with higher expression in RNAlater relative to liquid nitrogen experience disproportionate enrichment for functional categories, many of which are involved in RNA processing. This suggests that RNAlater may elicit a physiological response that has the potential to bias biological interpretations of expression studies. The biases introduced to observed gene expression arising from mimicking many field-based studies are substantial and should not be ignored.


Assuntos
Congelamento , Perfilação da Expressão Gênica/métodos , Preservação Biológica/métodos , Análise de Sequência de RNA/métodos , Animais , Peixes/genética
15.
Mol Ecol ; 27(22): 4397-4416, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30252986

RESUMO

Understanding the molecular basis of repeatedly evolved phenotypes can yield key insights into the evolutionary process. Quantifying gene flow between populations is especially important in interpreting mechanisms of repeated phenotypic evolution, and genomic analyses have revealed that admixture occurs more frequently between diverging lineages than previously thought. In this study, we resequenced 47 whole genomes of the Mexican tetra from three cave populations, two surface populations and outgroup samples. We confirmed that cave populations are polyphyletic and two Astyanax mexicanus lineages are present in our data set. The two lineages likely diverged much more recently than previous mitochondrial estimates of 5-7 mya. Divergence of cave populations from their phylogenetically closest surface population likely occurred between ~161 and 191 k generations ago. The favoured demographic model for most population pairs accounts for divergence with secondary contact and heterogeneous gene flow across the genome, and we rigorously identified gene flow among all lineages sampled. Therefore, the evolution of cave-related traits occurred more rapidly than previously thought, and trogolomorphic traits are maintained despite gene flow with surface populations. The recency of these estimated divergence events suggests that selection may drive the evolution of cave-derived traits, as opposed to disuse and drift. Finally, we show that a key trogolomorphic phenotype QTL is enriched for genomic regions with low divergence between caves, suggesting that regions important for cave phenotypes may be transferred between caves via gene flow. Our study shows that gene flow must be considered in studies of independent, repeated trait evolution.


Assuntos
Evolução Biológica , Cavernas , Characidae/genética , Fluxo Gênico , Genética Populacional , Animais , México , Modelos Genéticos , Fenótipo , Filogenia , Locos de Características Quantitativas
16.
G3 (Bethesda) ; 8(10): 3321-3329, 2018 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-30139765

RESUMO

Recent advances in genome resequencing have led to increased interest in prediction of the functional consequences of genetic variants. Variants at phylogenetically conserved sites are of particular interest, because they are more likely than variants at phylogenetically variable sites to have deleterious effects on fitness and contribute to phenotypic variation. Numerous comparative genomic approaches have been developed to predict deleterious variants, but the approaches are nearly always assessed based on their ability to identify known disease-causing mutations in humans. Determining the accuracy of deleterious variant predictions in nonhuman species is important to understanding evolution, domestication, and potentially to improving crop quality and yield. To examine our ability to predict deleterious variants in plants we generated a curated database of 2,910 Arabidopsis thaliana mutants with known phenotypes. We evaluated seven approaches and found that while all performed well, their relative ranking differed from prior benchmarks in humans. We conclude that deleterious mutations can be reliably predicted in A. thaliana and likely other plant species, but that the relative performance of various approaches does not necessarily translate from one species to another.


Assuntos
Variação Genética , Genoma de Planta , Genômica , Plantas/genética , Arabidopsis/genética , Duplicação Gênica , Genômica/métodos , Humanos , Mutação , Fenótipo , Polimorfismo de Nucleotídeo Único , Curva ROC , Reprodutibilidade dos Testes
17.
G3 (Bethesda) ; 8(9): 3049-3058, 2018 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-30030405

RESUMO

Tandem duplicate genes are proximally duplicated and as such occur in similar genomic neighborhoods. Using the maize B73 and PH207 de novo genome assemblies, we identified thousands of tandem gene duplicates that account for ∼10% of the annotated genes. These tandem duplicates have a bimodal distribution of ages, which coincide with ancient allopolyploidization and more recent domestication. Tandem duplicates are smaller on average and have a higher probability of containing LTR elements than other genes, suggesting origins in nonhomologous recombination. Within relatively recent tandem duplicate genes, ∼26% appear to be undergoing degeneration or divergence in function from the ancestral copy. Our results show that tandem duplicates are abundant in maize, arose in bursts throughout maize evolutionary history under multiple potential mechanisms, and may provide a substrate for novel phenotypic variation.


Assuntos
Domesticação , Evolução Molecular , Duplicação Gênica , Genes de Plantas , Zea mays/genética
18.
Plant J ; 93(1): 131-141, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29124819

RESUMO

Maize is a diverse paleotetraploid species with considerable 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. Differential fractionation refers to non-shared gene loss events between individuals following a whole-genome duplication event. 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 variably fractionated 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 than 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.


Assuntos
Variações do Número de Cópias de DNA , Genoma de Planta/genética , Zea mays/genética , Sintenia , Zea mays/metabolismo
19.
Plant Cell ; 29(6): 1196-1217, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28522548

RESUMO

We report a comprehensive toolkit that enables targeted, specific modification of monocot and dicot genomes using a variety of genome engineering approaches. Our reagents, based on transcription activator-like effector nucleases (TALENs) and the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system, are systematized for fast, modular cloning and accommodate diverse regulatory sequences to drive reagent expression. Vectors are optimized to create either single or multiple gene knockouts and large chromosomal deletions. Moreover, integration of geminivirus-based vectors enables precise gene editing through homologous recombination. Regulation of transcription is also possible. A Web-based tool streamlines vector selection and construction. One advantage of our platform is the use of the Csy-type (CRISPR system yersinia) ribonuclease 4 (Csy4) and tRNA processing enzymes to simultaneously express multiple guide RNAs (gRNAs). For example, we demonstrate targeted deletions in up to six genes by expressing 12 gRNAs from a single transcript. Csy4 and tRNA expression systems are almost twice as effective in inducing mutations as gRNAs expressed from individual RNA polymerase III promoters. Mutagenesis can be further enhanced 2.5-fold by incorporating the Trex2 exonuclease. Finally, we demonstrate that Cas9 nickases induce gene targeting at frequencies comparable to native Cas9 when they are delivered on geminivirus replicons. The reagents have been successfully validated in tomato (Solanum lycopersicum), tobacco (Nicotiana tabacum), Medicago truncatula, wheat (Triticum aestivum), and barley (Hordeum vulgare).


Assuntos
Engenharia Genética/métodos , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Hordeum/genética , Solanum lycopersicum/genética , RNA de Plantas/genética , Nucleases dos Efetores Semelhantes a Ativadores de Transcrição/genética , Triticum/genética
20.
Mol Ecol Resour ; 16(6): 1449-1454, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27480660

RESUMO

High-throughput sequencing has changed many aspects of population genetics, molecular ecology and related fields, affecting both experimental design and data analysis. The software package angsd allows users to perform a number of population genetic analyses on high-throughput sequencing data. angsd uses probabilistic approaches which can directly make use of genotype likelihoods; thus, SNP calling is not required for comparative analyses. This takes advantage of all the sequencing data and produces more accurate results for samples with low sequencing depth. Here, we present angsd-wrapper, a set of wrapper scripts that provides a user-friendly interface for running angsd and visualizing results. angsd-wrapper supports multiple types of analyses including estimates of nucleotide sequence diversity neutrality tests, principal component analysis, estimation of admixture proportions for individual samples and calculation of statistics that quantify recent introgression. angsd-wrapper also provides interactive graphing of angsd results to enhance data exploration. We demonstrate the usefulness of angsd-wrapper by analysing resequencing data from populations of wild and domesticated Zea. angsd-wrapper is freely available from https://github.com/mojaveazure/angsd-wrapper.


Assuntos
Biologia Computacional/métodos , Genética Populacional/métodos , Sequenciamento de Nucleotídeos em Larga Escala , Análise de Sequência de DNA/métodos , Variação Genética , Software , Zea mays/classificação , Zea mays/genética
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