Selective Breeding Have you ever seen a dog show on tv? How
many different types of dogs were there?!
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Selective Breeding We know all the dogs are the same species o
So how did we end up with so many different breeds?! Selective
Breeding allowing only animals with desired characteristics to
produce the next generation
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Selective Breeding People use selective breeding to pass
desired traits on to the next generation
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Hybridization Hybridization crossing dissimilar individuals to
bring together the best of both organisms o The offspring are
usually hardier o May include a fast growth rate with a resistance
to a particular disease
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Selective Breeding
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Inbreeding When it comes to dogs and cats, we found particular
traits we desired most We continued to breed these animals to
produce more with similar traits Inbreeding continued breeding of
individuals with similar characteristics
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Variation Variation exists in nature and is the key to the
survival of a group of organisms o Imagineeveryone in this room was
severely allergic to bee stings o Now, we drop a bees next right in
the middle of the room o What would happen?!
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Variation The bee allergy was an extreme example but you get
the point Populations need variation! Breeders can increase the
genetic variation in a population by inducing mutations, which are
the ultimate source of genetic variation
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Variation in Bacteria Bacteria reproduce very quickly! This
allows bacteria to evolve rapidly Scientists have created useful
mutant bacteria to do many jobs!
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New Plants Scientists can use drugs that prevent chromosome
separation during meiosis Polyploidy when a cell has many sets of
chromosomes o Animals usually die of this condition but plants can
survive o Often creates larger and strong plant species
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Polyploidy
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Manipulating DNA Genetic Engineering making changes to DNA
sequence Scientists can remove DNA from a cell, make copies and
alter the sequence to what they wish!
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Manipulating DNA In order to make copies of DNA scientists use
a technique called polymerase chain reaction PCR technique used to
copy DNA
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Manipulating DNA First the DNA must be extracted o Cells are
broken open, proteins are broken down and DNA is removed Then the
DNA is cut using restriction enzymes, which cut DNA at specific
sequences
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Gel Electrophoresis Scientists must then separate the DNA to be
analyzed Gel Electrophoresis DNA fragments are placed in one end of
a porous gel and an electric voltage is applied to the gel. Smaller
particles move faster.
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Gel Electrophoresis DNA is usually dyed with a fluorescent
marker to make it more visible
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How is this Useful!? Knowing the sequence of DNA allows
scientists to do some pretty incredible things! o Study specific
genes o Compare genes of other organisms o Helps researchers
discover the functions of genes o Can help to prevent or cure
diseases
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Transformation Transformation when a cell takes DNA from
outside the cell and integrates it with its own DNA Very easy to do
with bacteria o Bacteria readily accept plasmids, simple circular
structures containing recombinant DNA
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Transgenic Organisms Transgenic containing genes from other
organisms o Genetic engineering has improved biotechnology
Transgenic tobacco plant Contains genes from a firefly! Transgenic
tomatoes Ripening gene has been turned off so the tomatoes have a
longer shelf life
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Cloning A clone is a genetically identical organisms created
from a single cell. In 1997, Ian Wilmut was the first scientist to
clone a mammal o Dolly the sheep was the first mammal to be
successfully cloned!
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GMOs Genetically Modified Organism o Good or bad? o Safe? o How
far should we take it?
