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