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Grassa CJ, Weiblen GD, Wenger JP, Dabney C, Poplawski SG, Timothy Motley S, Michael TP, Schwartz CJ. A new Cannabis genome assembly associates elevated cannabidiol (CBD) with hemp introgressed into marijuana. New Phytol 2021; 230:1665-1679. [PMID: 33521943 PMCID: PMC8248131 DOI: 10.1111/nph.17243] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/18/2021] [Indexed: 05/20/2023]
Abstract
Demand for cannabidiol (CBD), the predominant cannabinoid in hemp (Cannabis sativa), has favored cultivars producing unprecedented quantities of CBD. We investigated the ancestry of a new cultivar and cannabinoid synthase genes in relation to cannabinoid inheritance. A nanopore-based assembly anchored to a high-resolution linkage map provided a chromosome-resolved genome for CBDRx, a potent CBD-type cultivar. We measured cannabinoid synthase expression by cDNA sequencing and conducted a population genetic analysis of diverse Cannabis accessions. Quantitative trait locus mapping of cannabinoids in a hemp × marijuana segregating population was also performed. Cannabinoid synthase paralogs are arranged in tandem arrays embedded in long terminal repeat retrotransposons on chromosome 7. Although CBDRx is predominantly of marijuana ancestry, the genome has cannabidiolic acid synthase (CBDAS) introgressed from hemp and lacks a complete sequence for tetrahydrocannabinolic acid synthase (THCAS). Three additional genomes, including one with complete THCAS, confirmed this genomic structure. Only cannabidiolic acid synthase (CBDAS) was expressed in CBD-type Cannabis, while both CBDAS and THCAS were expressed in a cultivar with an intermediate tetrahydrocannabinol (THC) : CBD ratio. Although variation among cannabinoid synthase loci might affect the THC : CBD ratio, variability among cultivars in overall cannabinoid content (potency) was also associated with other chromosomes.
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Affiliation(s)
| | - George D. Weiblen
- Department of Plant and Microbial BiologyUniversity of MinnesotaSaint PaulMN55108USA
| | - Jonathan P. Wenger
- Department of Plant and Microbial BiologyUniversity of MinnesotaSaint PaulMN55108USA
| | - Clemon Dabney
- Department of Plant and Microbial BiologyUniversity of MinnesotaSaint PaulMN55108USA
| | | | - S. Timothy Motley
- Department of InformaticsJ. Craig Venter InstituteLa JollaCA92037USA
| | - Todd P. Michael
- Department of InformaticsJ. Craig Venter InstituteLa JollaCA92037USA
- Present address:
Molecular and Cellular Biology LaboratorySalk Institute for Biological StudiesLa JollaCA92037USA
| | - C. J. Schwartz
- Sunrise Genetics Inc.Fort CollinsCO80525USA
- Present address:
Industrial Hemp Genetics LLCMadisonWI53705USA
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2
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Turner KG, Ostevik KL, Grassa CJ, Rieseberg LH. Genomic Analyses of Phenotypic Differences Between Native and Invasive Populations of Diffuse Knapweed (Centaurea diffusa). Front Ecol Evol 2021. [DOI: 10.3389/fevo.2020.577635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Invasive species represent excellent opportunities to study the evolutionary potential of traits important to success in novel environments. Although some ecologically important traits have been identified in invasive species, little is typically known about the genetic mechanisms that underlie invasion success in non-model species. Here, we use a genome-wide association (GWAS) approach to identify the genetic basis of trait variation in the non-model, invasive, diffuse knapweed [Centaurea diffusa Lam. (Asteraceae)]. To assist with this analysis, we have assembled the first draft genome reference and fully annotated plastome assembly for this species, and one of the first from this large, weedy, genus, which is of major ecological and economic importance. We collected phenotype data from 372 individuals from four native and four invasive populations of C. diffusa grown in a common environment. Using these individuals, we produced reduced-representation genotype-by-sequencing (GBS) libraries and identified 7,058 SNPs. We identify two SNPs associated with leaf width in these populations, a trait which significantly varies between native and invasive populations. In this rosette forming species, increased leaf width is a major component of increased biomass, a common trait in invasive plants correlated with increased fitness. Finally, we use annotations from Arabidopsis thaliana to identify 98 candidate genes that are near the associated SNPs and highlight several good candidates for leaf width variation.
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Hedrick BP, Heberling JM, Meineke EK, Turner KG, Grassa CJ, Park DS, Kennedy J, Clarke JA, Cook JA, Blackburn DC, Edwards SV, Davis CC. Digitization and the Future of Natural History Collections. Bioscience 2020. [DOI: 10.1093/biosci/biz163] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Abstract
Natural history collections (NHCs) are the foundation of historical baselines for assessing anthropogenic impacts on biodiversity. Along these lines, the online mobilization of specimens via digitization—the conversion of specimen data into accessible digital content—has greatly expanded the use of NHC collections across a diversity of disciplines. We broaden the current vision of digitization (Digitization 1.0)—whereby specimens are digitized within NHCs—to include new approaches that rely on digitized products rather than the physical specimen (Digitization 2.0). Digitization 2.0 builds on the data, workflows, and infrastructure produced by Digitization 1.0 to create digital-only workflows that facilitate digitization, curation, and data links, thus returning value to physical specimens by creating new layers of annotation, empowering a global community, and developing automated approaches to advance biodiversity discovery and conservation. These efforts will transform large-scale biodiversity assessments to address fundamental questions including those pertaining to critical issues of global change.
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Affiliation(s)
- Brandon P Hedrick
- Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana
- Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, Massachusetts
| | - J Mason Heberling
- Section of Botany, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania
| | - Emily K Meineke
- Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, Massachusetts
- Harvard University Herbaria, Harvard University, Cambridge, Massachusetts
| | - Kathryn G Turner
- Department of Biological Sciences, Idaho State University, Pocatello
| | | | - Daniel S Park
- Harvard University Herbaria, Harvard University, Cambridge, Massachusetts
| | - Jonathan Kennedy
- Harvard University Herbaria, Harvard University, Cambridge, Massachusetts
| | - Julia A Clarke
- Jackson School of Geosciences, University of Texas at Austin, Austin, Texas
| | - Joseph A Cook
- Department of Biology, University of New Mexico, Albuquerque
| | - David C Blackburn
- Florida Museum of Natural History, University of Florida, Gainesville
| | - Scott V Edwards
- Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, Massachusetts
| | - Charles C Davis
- Harvard University Herbaria, Harvard University, Cambridge, Massachusetts
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Marks RA, Smith JJ, Cronk Q, Grassa CJ, McLetchie DN. Genome of the tropical plant Marchantia inflexa: implications for sex chromosome evolution and dehydration tolerance. Sci Rep 2019; 9:8722. [PMID: 31217536 PMCID: PMC6584576 DOI: 10.1038/s41598-019-45039-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 05/29/2019] [Indexed: 01/29/2023] Open
Abstract
We present a draft genome assembly for the tropical liverwort, Marchantia inflexa, which adds to a growing body of genomic resources for bryophytes and provides an important perspective on the evolution and diversification of land plants. We specifically address questions related to sex chromosome evolution, sexual dimorphisms, and the genomic underpinnings of dehydration tolerance. This assembly leveraged the recently published genome of related liverwort, M. polymorpha, to improve scaffolding and annotation, aid in the identification of sex-linked sequences, and quantify patterns of sequence differentiation within Marchantia. We find that genes on sex chromosomes are under greater diversifying selection than autosomal and organellar genes. Interestingly, this is driven primarily by divergence of male-specific genes, while divergence of other sex-linked genes is similar to autosomal genes. Through analysis of sex-specific read coverage, we identify and validate genetic sex markers for M. inflexa, which will enable diagnosis of sex for non-reproductive individuals. To investigate dehydration tolerance, we capitalized on a difference between genetic lines, which allowed us to identify multiple dehydration associated genes two of which were sex-linked, suggesting that dehydration tolerance may be impacted by sex-specific genes.
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Affiliation(s)
- Rose A Marks
- Department of Biology, University of Kentucky, 101 Thomas Hunt Morgan Building, Lexington, KY, 40506, USA.
| | - Jeramiah J Smith
- Department of Biology, University of Kentucky, 101 Thomas Hunt Morgan Building, Lexington, KY, 40506, USA
| | - Quentin Cronk
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, BC, V6T 1Z4, Canada
| | - Christopher J Grassa
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, BC, V6T 1Z4, Canada
- Department of Organismic and Evolutionary Biology, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, MA, 02138, USA
| | - D Nicholas McLetchie
- Department of Biology, University of Kentucky, 101 Thomas Hunt Morgan Building, Lexington, KY, 40506, USA
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Hübner S, Bercovich N, Todesco M, Mandel JR, Odenheimer J, Ziegler E, Lee JS, Baute GJ, Owens GL, Grassa CJ, Ebert DP, Ostevik KL, Moyers BT, Yakimowski S, Masalia RR, Gao L, Ćalić I, Bowers JE, Kane NC, Swanevelder DZH, Kubach T, Muños S, Langlade NB, Burke JM, Rieseberg LH. Sunflower pan-genome analysis shows that hybridization altered gene content and disease resistance. Nat Plants 2019; 5:54-62. [PMID: 30598532 DOI: 10.1038/s41477-018-0329-0] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 11/15/2018] [Indexed: 05/22/2023]
Abstract
Domesticated plants and animals often display dramatic responses to selection, but the origins of the genetic diversity underlying these responses remain poorly understood. Despite domestication and improvement bottlenecks, the cultivated sunflower remains highly variable genetically, possibly due to hybridization with wild relatives. To characterize genetic diversity in the sunflower and to quantify contributions from wild relatives, we sequenced 287 cultivated lines, 17 Native American landraces and 189 wild accessions representing 11 compatible wild species. Cultivar sequences failing to map to the sunflower reference were assembled de novo for each genotype to determine the gene repertoire, or 'pan-genome', of the cultivated sunflower. Assembled genes were then compared to the wild species to estimate origins. Results indicate that the cultivated sunflower pan-genome comprises 61,205 genes, of which 27% vary across genotypes. Approximately 10% of the cultivated sunflower pan-genome is derived through introgression from wild sunflower species, and 1.5% of genes originated solely through introgression. Gene ontology functional analyses further indicate that genes associated with biotic resistance are over-represented among introgressed regions, an observation consistent with breeding records. Analyses of allelic variation associated with downy mildew resistance provide an example in which such introgressions have contributed to resistance to a globally challenging disease.
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Affiliation(s)
- Sariel Hübner
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada.
- Department of Biotechnology, Tel-Hai Academic College, Upper Galilee, Israel.
- MIGAL-Galilee Research Institute, Kiryat Shmona, Israel.
| | - Natalia Bercovich
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Marco Todesco
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jennifer R Mandel
- Department of Biological Sciences, University of Memphis, Memphis, TN, USA
| | | | | | - Joon S Lee
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gregory J Baute
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gregory L Owens
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Integrative Biology, University of California, Berkeley, CA, USA
| | - Christopher J Grassa
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Harvard University Herbaria , Cambridge, MA, USA
| | - Daniel P Ebert
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- The Beef Industry Centre, University of New England, Armidale, New South Wales, Australia
| | - Katherine L Ostevik
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Biology , Duke University, Durham, NC, USA
| | - Brook T Moyers
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO, USA
| | - Sarah Yakimowski
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Rishi R Masalia
- Department of Plant Biology, Miller Plant Sciences, University of Georgia, Athens, Georgia, USA
| | - Lexuan Gao
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Irina Ćalić
- Department of Plant Biology, Miller Plant Sciences, University of Georgia, Athens, Georgia, USA
| | - John E Bowers
- Department of Plant Biology, Miller Plant Sciences, University of Georgia, Athens, Georgia, USA
| | - Nolan C Kane
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Dirk Z H Swanevelder
- Agricultural Research Council, Biotechnology Platform, Private Bag X05, Onderstepoort, South Africa
| | - Timo Kubach
- SAP SE, Dietmar-Hopp-Allee 16, Walldorf, Germany
| | - Stephane Muños
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | | | - John M Burke
- Department of Plant Biology, Miller Plant Sciences, University of Georgia, Athens, Georgia, USA
| | - Loren H Rieseberg
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
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6
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Lee-Yaw JA, Grassa CJ, Joly S, Andrew RL, Rieseberg LH. An evaluation of alternative explanations for widespread cytonuclear discordance in annual sunflowers (Helianthus). New Phytol 2019; 221:515-526. [PMID: 30136727 DOI: 10.1111/nph.15386] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Accepted: 07/05/2018] [Indexed: 05/03/2023]
Abstract
Cytonuclear discordance is commonly observed in phylogenetic studies, yet few studies have tested whether these patterns reflect incomplete lineage sorting or organellar introgression. Here, we used whole-chloroplast sequence data in combination with over 1000 nuclear single-nucleotide polymorphisms to clarify the extent of cytonuclear discordance in wild annual sunflowers (Helianthus), and to test alternative explanations for such discordance. Our phylogenetic analyses indicate that cytonuclear discordance is widespread within this group, both in terms of the relationships among species and among individuals within species. Simulations of chloroplast evolution show that incomplete lineage sorting cannot explain these patterns in most cases. Instead, most of the observed discordance is better explained by cytoplasmic introgression. Molecular tests of evolution further indicate that selection may have played a role in driving patterns of plastid variation - although additional experimental work is needed to fully evaluate the importance of selection on organellar variants in different parts of the geographic range. Overall, this study represents one of the most comprehensive tests of the drivers of cytonuclear discordance and highlights the potential for gene flow to lead to extensive organellar introgression in hybridizing taxa.
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Affiliation(s)
- Julie A Lee-Yaw
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Christopher J Grassa
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Harvard University Herbaria, Cambridge, MA, 02138, USA
| | - Simon Joly
- Institut Recherche en Biologie Végétale, QC, H1X 2B2, Canada
- Jardin botanique de Montréal, Department Sciences Biologiques, Université de Montréal, Montréal, QC, H1X 2B2, Canada
| | - Rose L Andrew
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- School of Environmental and Rural Science, University of New England, Armidale, NSW, 2351, Australia
| | - Loren H Rieseberg
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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7
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Iha C, Grassa CJ, Lyra GDM, Davis CC, Verbruggen H, Oliveira MC. Organellar genomics: a useful tool to study evolutionary relationships and molecular evolution in Gracilariaceae (Rhodophyta). J Phycol 2018; 54:775-787. [PMID: 29989670 DOI: 10.1111/jpy.12765] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 06/29/2018] [Indexed: 06/08/2023]
Abstract
Gracilariaceae has a worldwide distribution including numerous economically important species. We applied high-throughput sequencing to obtain organellar genomes (mitochondria and chloroplast) from 10 species of Gracilariaceae and, combined with published genomes, to infer phylogenies and compare genome architecture among species representing main lineages. We obtained similar topologies between chloroplast and mitochondrial genomes phylogenies. However, the chloroplast phylogeny was better resolved with full support. In this phylogeny, Melanthalia intermedia is sister to a monophyletic clade including Gracilaria and Gracilariopsis, which were both resolved as monophyletic genera. Mitochondrial and chloroplast genomes were highly conserved in gene synteny, and variation mainly occurred in regions where insertions of plasmid-derived sequences (PDS) were found. In mitochondrial genomes, PDS insertions were observed in two regions where the transcription direction changes: between the genes cob and trnL, and trnA and trnN. In chloroplast genomes, PDS insertions were in different positions, but generally found between psdD and rrs genes. Gracilariaceae is a good model system to study the impact of PDS in genome evolution due to the frequent presence of these insertions in organellar genomes. Furthermore, the bacterial leuC/leuD operon was found in chloroplast genomes of Gracilaria tenuistipitata, G. chilensis, and M. intermedia, and in extrachromosomal plasmid of G. vermiculophylla. Phylogenetic trees show two different origins of leuC/leuD: genes found in chloroplast and plasmid were placed with proteobacteria, and genes encoded in the nucleus were close to Viridiplantae and cyanobacteria.
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Affiliation(s)
- Cintia Iha
- Department of Botany, Institute of Biosciences, University of São Paulo, R Matão 277, São Paulo, SP, 05508-090, Brazil
- School of BioSciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Christopher J Grassa
- Department of Organismic and Evolutionary Biology, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, Massachusetts, 02138, USA
| | - Goia de M Lyra
- Department of Organismic and Evolutionary Biology, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, Massachusetts, 02138, USA
- Laboratório de Algas Marinhas, Instituto de Biologia, Universidade Federal da Bahia, Rua Barão de Jeremoabo, s/n, Salvador, Bahia, 40170-115, Brazil
| | - Charles C Davis
- Department of Organismic and Evolutionary Biology, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, Massachusetts, 02138, USA
| | - Heroen Verbruggen
- School of BioSciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Mariana C Oliveira
- Department of Botany, Institute of Biosciences, University of São Paulo, R Matão 277, São Paulo, SP, 05508-090, Brazil
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Baute GJ, Kane NC, Grassa CJ, Lai Z, Rieseberg LH. Genome scans reveal candidate domestication and improvement genes in cultivated sunflower, as well as post-domestication introgression with wild relatives. New Phytol 2015; 206:830-8. [PMID: 25641359 DOI: 10.1111/nph.13255] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 11/24/2014] [Indexed: 05/22/2023]
Abstract
The development of modern crops typically involves both selection and hybridization, but to date most studies have focused on the former. In the present study, we explore how both processes, and their interactions, have molded the genome of the cultivated sunflower (Helianthus annuus), a globally important oilseed. To identify genes targeted by selection during the domestication and improvement of sunflower, and to detect post-domestication hybridization with wild species, we analyzed transcriptome sequences of 80 genotypes, including wild, landrace, and modern lines of H. annuus, as well as two cross-compatible wild relatives, Helianthus argophyllus and Helianthus petiolaris. Outlier analyses identified 122 and 15 candidate genes associated with domestication and improvement, respectively. As in several previous studies, genes putatively involved in oil biosynthesis were the most extreme outliers. Additionally, several promising associations were observed with previously mapped quantitative trait loci (QTLs), such as branching. Admixture analyses revealed that all the modern cultivar genomes we examined contained one or more introgressions from wild populations, with every chromosome having evidence of introgression in at least one modern line. Cumulatively, introgressions cover c. 10% of the cultivated sunflower genome. Surprisingly, introgressions do not avoid candidate domestication genes, probably because of the reintroduction of branching.
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Affiliation(s)
- Gregory J Baute
- Department of Botany, University of British Columbia, 3529-6270 University Blvd, Vancouver, BC, V6T 1Z4, Canada
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9
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Geraldes A, Farzaneh N, Grassa CJ, McKown AD, Guy RD, Mansfield SD, Douglas CJ, Cronk QCB. Landscape genomics of Populus trichocarpa: the role of hybridization, limited gene flow, and natural selection in shaping patterns of population structure. Evolution 2014; 68:3260-80. [PMID: 25065449 DOI: 10.1111/evo.12497] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 07/08/2014] [Indexed: 01/17/2023]
Abstract
Populus trichocarpa is an ecologically important tree across western North America. We used a large population sample of 498 accessions over a wide geographical area genotyped with a 34K Populus SNP array to quantify geographical patterns of genetic variation in this species (landscape genomics). We present evidence that three processes contribute to the observed patterns: (1) introgression from the sister species P. balsamifera, (2) isolation by distance (IBD), and (3) natural selection. Introgression was detected only at the margins of the species' distribution. IBD was significant across the sampled area as a whole, but no evidence of restricted gene flow was detected in a core of drainages from southern British Columbia (BC). We identified a large number of FST outliers. Gene Ontology analyses revealed that FST outliers are overrepresented in genes involved in circadian rhythm and response to red/far-red light when the entire dataset is considered, whereas in southern BC heat response genes are overrepresented. We also identified strong correlations between geoclimate variables and allele frequencies at FST outlier loci that provide clues regarding the selective pressures acting at these loci.
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Affiliation(s)
- Armando Geraldes
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
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10
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Andrew RL, Kane NC, Baute GJ, Grassa CJ, Rieseberg LH. Recent nonhybrid origin of sunflower ecotypes in a novel habitat. Mol Ecol 2013. [PMID: 23072494 DOI: 10.111/mec.12038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The genomics of local adaptation is an increasingly active field, providing insights into the forces driving ecological speciation and the repeatability of evolution. Demography and gene flow play an important role in determining the paths by which parallel evolution occurs and the genomic signatures of adaptation. In the annual sunflowers, hybridization between species has repeatedly led to the colonization of extreme habitats, such as sand dunes. In a new case of adaptation to sand dunes that occurs in populations of H. petiolaris growing at Great Sand Dunes National Park and Preserve (Colorado), we wished to determine the age and long-term migration patterns of the system, as well as its ancestry. We addressed these questions with restriction-associated DNA (RAD) sequence data, aligned to a reference transcriptome. In an isolation with migration model using RAD sequences, coalescent analysis showed that the dune ecotype originated since the last ice age, which is very recent compared with the hybrid dune species, H. anomalus. Large effective population sizes and substantial numbers of gene migrants per generation between dune and nondune ecotypes explained the highly heterogeneous divergence observed among loci. Analysis of RAD-derived SNPs identified heterogeneous divergence between the dune and nondune ecotypes, as well as identifying its nearest relative. Our results did not support the hypothesis that the dune ecotype has hybrid ancestry, suggesting that adaptation of sunflowers to dunes has occurred by multiple mechanisms. The ancestry and long-term history of gene flow between incipient sunflower species provides valuable context for our understanding of ecological speciation and parallel adaptation.
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Affiliation(s)
- Rose L Andrew
- Department of Botany, University of British Columbia, Vancouver, BC, Canada.
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11
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Geraldes A, Difazio SP, Slavov GT, Ranjan P, Muchero W, Hannemann J, Gunter LE, Wymore AM, Grassa CJ, Farzaneh N, Porth I, McKown AD, Skyba O, Li E, Fujita M, Klápště J, Martin J, Schackwitz W, Pennacchio C, Rokhsar D, Friedmann MC, Wasteneys GO, Guy RD, El-Kassaby YA, Mansfield SD, Cronk QCB, Ehlting J, Douglas CJ, Tuskan GA. A 34K SNP genotyping array for Populus trichocarpa: design, application to the study of natural populations and transferability to other Populus species. Mol Ecol Resour 2013; 13:306-23. [PMID: 23311503 DOI: 10.1111/1755-0998.12056] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 11/30/2012] [Accepted: 12/03/2012] [Indexed: 02/03/2023]
Abstract
Genetic mapping of quantitative traits requires genotypic data for large numbers of markers in many individuals. For such studies, the use of large single nucleotide polymorphism (SNP) genotyping arrays still offers the most cost-effective solution. Herein we report on the design and performance of a SNP genotyping array for Populus trichocarpa (black cottonwood). This genotyping array was designed with SNPs pre-ascertained in 34 wild accessions covering most of the species latitudinal range. We adopted a candidate gene approach to the array design that resulted in the selection of 34 131 SNPs, the majority of which are located in, or within 2 kb of, 3543 candidate genes. A subset of the SNPs on the array (539) was selected based on patterns of variation among the SNP discovery accessions. We show that more than 95% of the loci produce high quality genotypes and that the genotyping error rate for these is likely below 2%. We demonstrate that even among small numbers of samples (n = 10) from local populations over 84% of loci are polymorphic. We also tested the applicability of the array to other species in the genus and found that the number of polymorphic loci decreases rapidly with genetic distance, with the largest numbers detected in other species in section Tacamahaca. Finally, we provide evidence for the utility of the array to address evolutionary questions such as intraspecific studies of genetic differentiation, species assignment and the detection of natural hybrids.
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Affiliation(s)
- A Geraldes
- Department of Botany, University of British Columbia, Vancouver, BC, V6T1Z4, Canada.
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Wang Z, Hobson N, Galindo L, Zhu S, Shi D, McDill J, Yang L, Hawkins S, Neutelings G, Datla R, Lambert G, Galbraith DW, Grassa CJ, Geraldes A, Cronk QC, Cullis C, Dash PK, Kumar PA, Cloutier S, Sharpe AG, Wong GKS, Wang J, Deyholos MK. The genome of flax (Linum usitatissimum) assembled de novo from short shotgun sequence reads. Plant J 2012; 72:461-73. [PMID: 22757964 DOI: 10.1111/j.1365-313x.2012.05093.x] [Citation(s) in RCA: 252] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Flax (Linum usitatissimum) is an ancient crop that is widely cultivated as a source of fiber, oil and medicinally relevant compounds. To accelerate crop improvement, we performed whole-genome shotgun sequencing of the nuclear genome of flax. Seven paired-end libraries ranging in size from 300 bp to 10 kb were sequenced using an Illumina genome analyzer. A de novo assembly, comprised exclusively of deep-coverage (approximately 94× raw, approximately 69× filtered) short-sequence reads (44-100 bp), produced a set of scaffolds with N(50) =694 kb, including contigs with N(50)=20.1 kb. The contig assembly contained 302 Mb of non-redundant sequence representing an estimated 81% genome coverage. Up to 96% of published flax ESTs aligned to the whole-genome shotgun scaffolds. However, comparisons with independently sequenced BACs and fosmids showed some mis-assembly of regions at the genome scale. A total of 43384 protein-coding genes were predicted in the whole-genome shotgun assembly, and up to 93% of published flax ESTs, and 86% of A. thaliana genes aligned to these predicted genes, indicating excellent coverage and accuracy at the gene level. Analysis of the synonymous substitution rates (K(s) ) observed within duplicate gene pairs was consistent with a recent (5-9 MYA) whole-genome duplication in flax. Within the predicted proteome, we observed enrichment of many conserved domains (Pfam-A) that may contribute to the unique properties of this crop, including agglutinin proteins. Together these results show that de novo assembly, based solely on whole-genome shotgun short-sequence reads, is an efficient means of obtaining nearly complete genome sequence information for some plant species.
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Affiliation(s)
- Zhiwen Wang
- BGI-Shenzen, Bei Shan Industrial Zone, Yantian District, Shenzhen 518083, China
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Renaut S, Grassa CJ, Moyers BT, Kane NC, Rieseberg LH. The Population Genomics of Sunflowers and Genomic Determinants of Protein Evolution Revealed by RNAseq. Biology (Basel) 2012; 1:575-96. [PMID: 24832509 PMCID: PMC4009819 DOI: 10.3390/biology1030575] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 10/09/2012] [Accepted: 10/12/2012] [Indexed: 11/17/2022]
Abstract
Few studies have investigated the causes of evolutionary rate variation among plant nuclear genes, especially in recently diverged species still capable of hybridizing in the wild. The recent advent of Next Generation Sequencing (NGS) permits investigation of genome wide rates of protein evolution and the role of selection in generating and maintaining divergence. Here, we use individual whole-transcriptome sequencing (RNAseq) to refine our understanding of the population genomics of wild species of sunflowers (Helianthus spp.) and the factors that affect rates of protein evolution. We aligned 35 GB of transcriptome sequencing data and identified 433,257 polymorphic sites (SNPs) in a reference transcriptome comprising 16,312 genes. Using SNP markers, we identified strong population clustering largely corresponding to the three species analyzed here (Helianthus annuus, H. petiolaris, H. debilis), with one distinct early generation hybrid. Then, we calculated the proportions of adaptive substitution fixed by selection (alpha) and identified gene ontology categories with elevated values of alpha. The “response to biotic stimulus” category had the highest mean alpha across the three interspecific comparisons, implying that natural selection imposed by other organisms plays an important role in driving protein evolution in wild sunflowers. Finally, we examined the relationship between protein evolution (dN/dS ratio) and several genomic factors predicted to co-vary with protein evolution (gene expression level, divergence and specificity, genetic divergence [FST], and nucleotide diversity pi). We find that variation in rates of protein divergence was correlated with gene expression level and specificity, consistent with results from a broad range of taxa and timescales. This would in turn imply that these factors govern protein evolution both at a microevolutionary and macroevolutionary timescale. Our results contribute to a general understanding of the determinants of rates of protein evolution and the impact of selection on patterns of polymorphism and divergence.
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Affiliation(s)
- Sébastien Renaut
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada.
| | - Christopher J Grassa
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - Brook T Moyers
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - Nolan C Kane
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - Loren H Rieseberg
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
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Andrew RL, Kane NC, Baute GJ, Grassa CJ, Rieseberg LH. Recent nonhybrid origin of sunflower ecotypes in a novel habitat. Mol Ecol 2012; 22:799-813. [DOI: 10.1111/mec.12038] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 07/27/2012] [Accepted: 07/30/2012] [Indexed: 02/04/2023]
Affiliation(s)
- Rose L. Andrew
- Department of Botany; University of British Columbia; 3529-6270 University Blvd; Vancouver; BC; Canada; V6T 1Z4
| | - Nolan C. Kane
- Department of Botany; University of British Columbia; 3529-6270 University Blvd; Vancouver; BC; Canada; V6T 1Z4
| | - Greg J. Baute
- Department of Botany; University of British Columbia; 3529-6270 University Blvd; Vancouver; BC; Canada; V6T 1Z4
| | - Christopher J. Grassa
- Department of Botany; University of British Columbia; 3529-6270 University Blvd; Vancouver; BC; Canada; V6T 1Z4
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Grassa CJ, Kulathinal RJ. Elevated Evolutionary Rates among Functionally Diverged Reproductive Genes across Deep Vertebrate Lineages. Int J Evol Biol 2011; 2011:274975. [PMID: 21811675 PMCID: PMC3147129 DOI: 10.4061/2011/274975] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 05/17/2011] [Accepted: 05/23/2011] [Indexed: 11/24/2022]
Abstract
Among closely related taxa, proteins involved in reproduction generally evolve more rapidly than other proteins. Here, we apply a functional and comparative genomics approach to compare functional divergence across a deep phylogenetic array of egg-laying and live-bearing vertebrate taxa. We aligned and annotated a set of 4,986 1 : 1 : 1 : 1 : 1 orthologs in Anolis carolinensis (green lizard), Danio rerio (zebrafish), Xenopus tropicalis (frog), Gallus gallus (chicken), and Mus musculus (mouse) according to function using ESTs from available reproductive (including testis and ovary) and non-reproductive tissues as well as Gene Ontology. For each species lineage, genes were further classified as tissue-specific (found in a single tissue) or tissue-expressed (found in multiple tissues). Within independent vertebrate lineages, we generally find that gonadal-specific genes evolve at a faster rate than gonadal-expressed genes and significantly faster than non-reproductive genes. Among the gonadal set, testis genes are generally more diverged than ovary genes. Surprisingly, an opposite but nonsignificant pattern is found among the subset of orthologs that remained functionally conserved across all five lineages. These contrasting evolutionary patterns found between functionally diverged and functionally conserved reproductive orthologs provide evidence for pervasive and potentially cryptic lineage-specific selective processes on ancestral reproductive systems in vertebrates.
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Affiliation(s)
- Christopher J Grassa
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
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