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Frontiers of Biotechnology. Changing the Living World. These dogs are all of the same species Where do their striking differences in appearance come from?. Beef Cattle Breeds. Selective Breeding.
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Changing the Living World • These dogs are all of the same species • Where do their striking differences in appearance come from?
Selective Breeding • A method of improving a species by allowing only those individual organisms with desired characteristics to produce the next generation • Nearly all domestic animals and crop plants have been produced by selective breeding
Luther Burbank • American botanist 1849 – 1926 • Developed more than 800 varieties of plants in his lifetime • Developed disease resistant potato to help fight Irish potato blight
Hybridization • Breeding technique that involves crossing dissimilar individuals to bring together the best traits of both organisms
Inbreeding • The continued breeding of individuals with similar characteristics • Breeds developed through inbreeding are genetically similar • Increased chances of bringing together two recessive alleles for genetic defects
Increasing Variation • Breeders can increase genetic variation in a population by • Inducing mutations • Mutations are the ultimate source of genetic variability
Variation – New Kinds of Bacteria • Mutation rates increased by using radiation or chemicals • Increases the chances of producing a useful mutant • Hundreds of useful bacterial strains have been produced
Variation – New Kinds of Plants • Polyploid plants • Plants with double or triple the normal number of chromosomes • Produced by using drugs that prevent chromosomes from separating during meiosis
Manipulating DNATools of Molecular Biology • DNA extraction • DNA can be extracted from cells by simple chemical procedures • Cutting DNA • DNA can be cut into smaller fragments by the use of restriction enzymes • Separating DNA • Gel electrophoresis – procedure used to produce DNA “fingerprints”
Cell Transformation • During transformation, a cell takes in DNA from outside the cell • External DNA becomes a part of the cell’s DNA
Transforming Animal Cells • Can be transformed in some of the same ways as plant cells • Has applications in gene replacement therapy
Applications of Genetic Engineering • Transgenic organisms • Transgenic organisms contain genes from other organisms • Transgenic microorganisms • Transgenic animals • Transgenic plants
Cloning • Clone • A member of a population of genetically identical cells produced from a single cell
Cloning Dolly A donor cell is taken from a sheep’s udder. The nucleus of this cell will provide the genetic material for the cloned lamb.
An egg cell is taken from a second sheep. The nucleus of the cell is removed. This cell does not supply any genetic material for the cloned lamb.
The donor cell (with a nucleus) and the egg cell (without a nucleus) are fused using an electric shock.
The fused cells begin dividing normally, forming an embryo. The embryo is placed in the uterus of a foster mother.
The embryo develops into a lamb, Dolly. Dolly is a clone of the sheep that donated the udder cell.
A cross between dissimilar individuals to bring together their best characteristics is called a. genetic engineering b. inbreeding c. hybridization d. sequencing
Crossing individuals with similar characteristics so that those characteristics will appear in the offspring is called a. inbreeding b. electrophoresis c. hybridization d. genetic engineering
Varieties of purebred dogs are maintained by a. selective breeding b. hybridization c. inbreeding d. genetic engineering
Changing the DNA of an organism is called a. genetic engineering b. hybridization c. selective breeding d. inbreeding