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Paul VincelliExtension Professor andProvost’s Distinguished Service ProfessorUniversity of Kentucky
GMO Crops: Basic Concepts, Risks and Benefits
Part I. GMO Crops: Basic Concepts
Word processing: a metaphor for how genetic engineering works
Nature, the “Mother of all Frankenfoods”
Compare/contrast to other crop improvement techniques
Discussion: Future programming needs
Part II. GMO Crops: Risks and Benefits
Examples of present-day GMO crops, and impacts
Potential risks of GMO crops Potential benefits of GMO crops Discussion: Future programming
needs
Google searches for “GMO”
www.google.com/trends
2005 2007 2009 2011 2013
Relative number of searches
Scientific information is necessary but insufficient
http://prestonhull.bpweb.net/Fight.html
Some recommendations on communicating science
All crops are genetically modified
Image from http://evolution.berkeley.edu/evolibrary/news/070201_corn
All crops are genetically modified
http://vozpopuli.com/next/50980-asi-hemos-moldeado-geneticamente-el-tomate-en-los-ultimos-10-000-anos?utm_content=buffer66b36&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer
Crops without genetic modification
http://www.geneticliteracyproject.org/2014/06/19/how-your-food-would-look-if-not-genetically-modified-over-millennia/
Gene expression
DNA RNA Protein
Conventional breeding vs. transgenesis (GMO)
http://www.csiro.au/files/images/ph8g.jpg
Plant transformationAgrobacterium
Biolistics
http://www.genomenewsnetwork.org/articles/12_01/A_tumefaciens_genome.shtml https://physics.ucsd.edu/~groisman/Gene%20guns.html
Word processing
A metaphor for how genetic engineering works
Is genetic engineering “unnatural”?
“Ick” vs. “Cool!”
Some natural genetic processes
“Scrambling” of genetic material (within an organism)
Transfer of gene fragments (between organisms)
“Scrambling” of genetic material (within an organism)
Transposons (“jumping genes”)
https://www.broadinstitute.org/files/news/stories/full/transposons_720x720_v2.jpg
Some transposons are active in crops
New insertions in rice indicated by arrows
Naito et al, 2006. Dramatic amplification of a rice transposable element during recent domestication. PNAS 103, 17620
Transposon-produced defect in chlorophyll biosynthesis
Dooner and Weil, 2013. Transposons and gene creation. In Fedoroff, 2013. Plant Transposons and Genome Dynamics in Evolution. J. Wiley and Sons.
Transposons (“jumping genes”)
From Feschotte et al. 2002. Nature Review Genetics 3:329
Chimerical genes created by one of Nature’s “cut-and-paste” tools
Normal wp allele
wp alleles with captured fragments of exons and introns
Zabala and Vodkin, 2007. Novel exon combinations generated by alternative splicing of gene fragments mobilized by a CACTA transposon in Glycine max. BMC Plant Biology 7:38
Transposable elements in monocot crops
From Plant Transposable Elements, 2012
Transfer of gene fragments (between organisms)
Paradigm: Evolutionary branches do not share genetic material
http://www.dnabaser.com/articles/phylogenetic-tree/phylogenetic-tree-big.jpg
Proposed inter-kingdom transfer of GT28 domain
From: Song D, Cho WK, Park S-H, Jo Y, Kim K-H (2013) Evolution of and Horizontal Gene Transfer in the Endornavirus Genus. PLoS ONE 8(5): e64270. doi:10.1371/journal.pone.0064270
www.pnas.org/cgi/doi/10.1073/pnas.1319929111
Sun B-F, et al. (2013) Multiple Interkingdom Horizontal Gene Transfers in Pyrenophora and Closely Related Species andTheir Contributions to Phytopathogenic Lifestyles. PLoS ONE 8(3): e60029. doi:10.1371/journal.pone.0060029
5:2876 | DOI: 10.1038/ncomms3876
Genome Research, 2014, http://www.genome.org/cgi/doi/10.1101/gr.164400.113.
Walshet al, 2013, PNAS 110:1012-1016
http://www.pnas.org/content/early/2012/01/23/1114076109
Nature Reviews: Genetics, 2008, doi:10.1038/nrg2386
Metcalf et al, 2014. Antibacterial gene transfer across the tree of life. eLife 2014;3:e04266. DOI: 10.7554/eLife.04266
Horizontal gene transfer is “fairly common in nature.”
Bioessays , 868–875, 2013
Plant genomes are highly dynamic
Some natural genetic processes
“Scrambling” of genetic material (within an organism)
Transfer of gene fragments (between organisms)
Generating biodiversity
Basis for selection of adapted biotypes
Genetic engineering vs. other disruptive breeding techniques
Protoplast fusion overcomes hybridization barriers
Image from http://www.syntheticsomaticseeds.org/protoplast-fusion
Through protoplast fusion, “…we can create new species of plants…”
Forced crossing can be highly mutagenic
Wang et al, 2005. Extensive de Novo Genomic Variation in Rice Induced by Introgression From Wild Rice (Zizania latifolia Griseb.). Genetics 170: 1945–1956
Tissue culture: somaclonal variation & activation of jumping genes
See: Scnnell et al, 2015. A comparative analysis of insertional effects in genetically engineered plants: considerations for pre-market assessments. Transgenic Research 24:1-7, etc.
Mutation breeding: unknown genetic changes
De: Bjorn Sigurbjornsson, “Induced Mutations in Plants.” Copyright © 1970 by Scientific American, Inc. All rights reserved.
http://www.wasatchorganics.com/products-page/grapefruit/organic-henderson-grapefruit-duplicate/
Other methods of crop improvement
Schnell et al, 2015. A comparative analysis of insertional effects in genetically engineered plants: considerations for pre-market assessments. Transgenic Research DOI 10.1007/s11248-014-9843-7
New developments in genetic engineering
Extremely targeted genetic changes
Gene expression
DNA RNA Protein
Gene silencing (RNAi)
DNA ProteindsRNA
Potato with 50% less acrylamide, less bruising
Pesticidal RNAs
Types of mutations
http://evolution.berkeley.edu/evosite/evo101/IIIC3aTypes.shtml
Substitution Insertion Deletion
Genome editing: mutations in rice indistinguishable from spontaneous ones
Shan et al, 2013. Targeted genome modification of crop plants using a CRISPR-Cas system. Nature Biotechnology 31:686
Red=insertions, dashes=deletions
Cisgenesis
http://www.biofortified.org/2013/08/cisgenesis-new-dawn-on-food-production/
Discussion
Questions/concerns Future programming needs
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