Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Hopes for the future: new breeding technologies Helen Sang The Roslin Institute University of Edinburgh www. bbsrc.ac.uk “Genome editing” • DNA is packaged into chromosomes • Humans have 1.8metres of DNA, wheat 5X longer • Each chromosome is a linear array of genes, each of a unique sequence “Genome editing” Genome editing: “molecular scissors” identify a specified gene sequence and then cut the DNA “Genome editing” The DNA at the cut site may be replaced with a very short stretch of new DNA: making a specific change in a gene is possible CRISPR: sequence-specific editing • CRISPRs:most recently developed molecular scissors • CRISPRS very efficient in finding the target sequence and cutting DNA • Cut DNA may be repaired causing a novel mutation • Cut DNA may be repaired, introducing a precise genetic change Powdery mildew in wheat: CRISPR mutation of TaMLOabd Yanpeng Wang, Xi Cheng,Qiwei Shan,Yi Zhang,Jinxing Liu,Caixia Gao& Jin-Long Qiu Nature Biotechnology 32, 947–951 (2014) Mutation of a target gene: resistance to PRRS a major viral disease of pigs University of Missouri and Genus PLC Gene editing in a Brassica crop: pod shatter in oil seed rape a b c Wild type Edited d Wild type Edited • A single mutation in a model brassica species stops pod shatter • Introduction of a similar mutation in oil seed rape should greatly reduce losses of seed Lawrenson et al. Genome Biology 2015 Aquaculture: main source of fish protein globally, Require source of omega3 fatty acids in diet Wild fish mainly take up omega3 LC-PUFAs via the food chain Primary producers of omega-3 LCPUFAs are algae Farmed fish has to be fed with omega-3 LCPUFAs Need a sustainable source of omega-3 LCPUFAs Reduction fisheries are limiting growth of aquaculture Can an oil seed crop be genetically altered to form a source of omega3 fatty acids for farmed fish food? http://www.rothamsted.ac .uk/camelina-2015 Nitrogen availability limits crop yields Legumes are the prototype for self-fertilising crops Aim: genetically alter cereals to fix nitrogen, adopting the mechanisms used by legumes e.g.peas https://www.jic.ac.uk/ New breeding technologies using molecular techniques • Simple gene mutation: equivalent mutations could exist “naturally”; much faster than breeding • Move gene variant between breeds: avoid loss of genetic merit; much faster than breeding • Move gene variants between species; cannot be achieved by breeding • Introduce novel genes not present in particular species e.g. blight resistance in potatoes; may involve introduction of new DNA sequences • Introduce novel genetic pathways to enhance qualities; complex combination of very small genetic changes and introduction of new gene sequences Parallel increase in knowledge of genome sequences/gene structure/gene function in crops and farmed animals (and their diseases) results in opportunities to use GE to increase productivity faster and in novel ways BUT!!!!! • What are the most useful/practical applications? • How will genome edited crops be regulated? • Will they be accepted by consumers? • Will more complex combinations of GE and GM become accepted? More information: Wendy Harwood [email protected] https://www.jic.ac.uk/ Matina Tsalavouta [email protected] http://www.rothamsted.ac.uk/ Replicate a “natural mutation” in different breeds Recombinetics • Beef cattle are hornless, the polled mutation • majority of dairy cattle have horns that are removed in calves. • Gene editing has been used to make dairy cattle genetically hornless