Transcript Chapter 12
Chapter 12 Genetic Engineering 12-1 Modifying the Living World What do the terms selective breeding, inbreeding, and hybridization mean? How can mutations be useful to humans? Breeding Strategies Farmers and ranchers have been trying to improve organisms for years By selecting the most productive animals for the next generation, people have found that the domesticated organisms' productivity can be increased Can be done by selective breeding, inbreeding, and hybridization http://www.wisdompanelpro.com/breedinfo/ Selective Breeding Selective breeding-selecting a few individuals to serve as parents for the next generation Farmers are able to increase the yield of crops & the milk production of animals by only breeding animals that produce the most Almost all the present-day crops were developed through selective breeding http://dels-old.nas.edu/plant_genome/booklet_part_2.shtml http://www.tutorvista.com/content/biology/biology-ii/heredity-and-evolution/comparative-study.php Inbreeding Once the breeder has developed a good stock of organisms, he wants to maintain that similar stock Inbreeding-crossing individuals with similar characteristics so that those characteristics will appear in their offspring (usually closely related) Many varieties of purebred dogs are maintained by inbreeding http://phys.org/news138025054.html Inbreeding is useful for getting certain characteristics, it does have risks The chances that recessive genetic disorders will show up are higher because most of the individuals have similar DNA Examples: joint problems and blindness in golden retrievers and German shepherds is a result of this http://fhoguide.com/FHO-hip-problems.php Hybridization Hybridization- cross between members of different (but related) species This produces hybrids that are usually hardier than either of the parents (hybrid vigor) Example: modern hybrid corn produces as much as ten times the crop per acre of older varieties of corn. Hybrid vigor http://passel.unl.edu/pages/informationmodule.php?idinformationmodule=1075412493&topicorder=9&maxto=12&minto=1 Mutations: Producing New Kinds of Organisms Selective breeding only involves characteristics that already exist Mutations can sometimes produce new organisms with new characteristics If mutations are wanted, the breeders can produce new populations with those desired characteristics This definitely scares the mice!! / http://www.patheos.com/blogs/unreasonablefaith/2009/08/mouse-gets-benefitical-mutation-but-doesnt-evolve-into-crododuck But seriously…seedless oranges http://coastgrown.com/shop/product.php?productid=98 A mutation could take a long time to ever happen so breeders my increase the chances of a mutation Mutagens-substances or agents which include radiation and chemicals that cause mutations Mutations are usually harmful but with luck and perseverance, a few mutants can be produced with desirable characteristics Could get some like this…probs not http://www.dan-dare.org/FreeFun/Games/CartoonsMoviesTV/Pokemon2.htm Mutagenesis (using mutagens to increase mutation rate) is very useful with bacteria With their small size and so many of them, they are able to change at a much greater scale They are able to create useful bacteria strains…one that even can digest oil Oil digesting bacteria http://news.softpedia.com/news/Bacteria-Eating-Up-Oil-Spills-and-Producing-Biodegradable-Plastic-18787.shtml 12-2 Genetic Engineering: Technology and Heredity What is genetic engineering? How does it affect DNA? How do the various techniques of genetic engineering work? What are some applications of genetic engineering? Genetic engineering Biologists have developed ways that affect DNA directly They can engineer a sec of genetic changes directly into an organism’s DNA This is called genetic engineering The techniques of genetic engineering http://www.ces.ncsu.edu/resources/crops/ag546-1/ Restriction Enzymes Restriction enzymes-proteins that cut out specific DNA sequences in genes These recognize a site of four to six nucleotides and then cut it out of the strand of DNA These make it possible to cut and isolate specific DNA parts http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/R/RestrictionEnzymes.html DNA Recombination DNA fragments then need to be placed into part of the recipient cell’s genetic material The DNA is then combined with bacterial cells DNA which are known as plasmids Restriction enzymes cut the plasmids at certain points so that the new DNA fragments can combine with the “sticky ends” of the bacterial DNA http://en.wikipedia.org/wiki/Recombinant_DNA This fuses DNA of two different organisms Combined DNA is known as recombinant DNA since DNA from two sources have been recombined DNA Insertion How does this then get back into living cells? The easiest way is to place it into bacterial cells and then grow them with the desired DNA This is known as DNA cloning because growing a large number of cells grown from a single cell is known as a clone DNA can also be inserted into plants and animals Done by insertion with a glass needle and fusion with plama-like DNA DNA sequencing The DNA then needs to be read Only one stand is read but DNA cloning is done to see multiple copies DNA is broken into pieces with chemical treatments When separated they are able to see the positions of the bases on the original strands Separated by electrophoresis DNA sequencing with electrophoresis http://en.wikipedia.org/wiki/DNA_sequencing Engineering New Organisms Organisms that contain such foreign genes are said to be transgenic http://www.scq.ubc.ca/the-new-macdonald-pharm/ Transgenic bacteria Can create human growth hormones and insulin which can help fight diabetes http://tle.westone.wa.gov.au/content/file/c0a7f9da-2dc9-b549-578a-0f1a8921d148/1/bio_science_3b.zip/content/001_dna/page_15.htm Transgenic plants Tobacco plant with Firefly genes http://www.sciencedaily.com/articles/t/transgenic_plants.htm CMV virus resistance http://web.entomology.cornell.edu/shelton/cornell-biocontrol-conf/talks/gonsalves.html Transgenic animals http://www.nature.com/nbt/journal/v26/n11/full/nbt1108-1205.html Transgenic Carp http://www.cafs.ac.cn/english/Research-Priorities.html Transgenic Mice http://www.hms.harvard.edu/agingresearch/pages/whoweare.htm