Name _______________________________________________________________
Period _____________
Application of Genetics Notes - 2015
Testing for Alleles
 Because genetic disorders have slightly different DNA __________________ from their normal counterparts, a
variety of genetic tests have been developed that can spot those _____________________.
 Enables prospective parents to see if they are carriers of a genetic disorder such as Tay-Sachs or cystic
fibrosis.
Genetic Tests
 Genetic tests are now available for hundreds of disorders.
 Making it possible to determine whether prospective parents risk passing such ___________ to their
children.
 DNA testing can pinpoint the exact ___________ ___________ of a disorder, making it possible to
develop more effective __________________ for individuals affected by genetic disease.
Gene Therapy
 Process of changing the _________________ that causes a genetic disorder in order to eliminate the
____________ of the disorder
 In _______________________, an absent or _____________ gene is replaced by a _____________, working
gene.
 Replacing a mutated gene:
 A gene called p53 normally prevents _________________ growth in your body. If doctors could replace
the defective p53 gene that might trigger the __________________ cells to die.
 Fixing a mutated gene:
 _________________________ genes that cause disease could be turned off so that they no longer
promote disease, or healthy genes that help __________________ disease could be turned on so that
they can inhibit the disease.
 Making diseased cells more evident to the immune system.
 In some cases, your immune system doesn't attack __________________ cells because it doesn't
recognize them as intruders. Doctors could use _____________ ___________________ to train your
immune system to recognize the cells that are a threat.
History of Gene Therapy
 First authorized attempt to cure a human genetic disorder by gene transfer occurred in ______.
 In 1999, a young French girl was ___________ of an inherited immune disorder when cells from her
bone marrow were removed, modified in the laboratory, and then placed back in her body.
Gene Therapy: Using Viruses
 ____________ are often used because of their ability to enter a cell's DNA.
1. The virus particles are modified so that they cannot cause ______________.
2. Then, a DNA fragment containing a ______________ _________ is spliced to viral DNA.
3. The patient is then infected with the _____________ virus particles, which should carry the
___________ into cells to correct genetic defects.
Other Genetic Testing Methods: DNA Fingerprinting
 ______________________________________ - Analysis of sections of DNA that have little or no known
function, but vary widely from one individual to another, in order to___________________ individuals.
o Does not analyze the cell's most ___________________ genes because they are largely ________________
among most people.
o Samples can be obtained from ______________, sperm, and even ____________ strands with tissue at the
base.
o Used in ______________________: Has helped convict criminals as well as overturn many convictions
o Used to determine _________________________
Gene Therapy: A Promising Cure?
 Unfortunately, gene therapy experiments have _________ always been _______________.
 Attempts to treat cystic fibrosis by _____________ genetically engineered
______________ into the breathing passages have not produced a lasting cure.
 For all the promise it holds, in most cases gene therapy remains a _________________,
___________________ procedure.
Genetic Engineering
Genetic Variation
• You can compare dogs of every breed imaginable!
• There is an enormous range of characteristics that are the result of _______________________.
• The differences among breeds of dogs are so great that someone might think that many of these breeds are
different species.
• They're not, of course, but ____________________________________________________?
Selective Breeding
• The answer, of course, is that _____________________.
– Humans have kept and bred dogs for thousands of years, always looking to produce animals that might
be better hunters, better retrievers, or better companions.
• By _____________________________, allowing only those animals with ________________________________
____________________, humans have produced many different ______________________________________.
Selective Breeding
• Humans use selective breeding, which takes advantage of _________________ ___________________ genetic
variation in plants, animals, and other organisms, to pass desired traits on to the next generation of organisms.
– Nearly all _________________ animals—including horses, cats, and farm animals—and most
___________ plants have been produced by selective breeding.
Selective Breeding
• The ancestor of modern ___________ had ___________ kernels,
each protected by a tough husk.
• Domestication of maize, which began thousands of years ago,
selected for large sheathed cobs containing _______________
kernels without husks.
Hybridization
• Hybridization- ________________________________________________________________________________
___________________________________________________________________________________________
– _______________, the individuals produced by such crosses, are often _______________ than either of
the parents.
Inbreeding
• ___________________________________________________________________________________________
___________________________________________________________________________ inbreeding.
• ___________________ is the continued breeding of individuals with ______________ characteristics.
• The many breeds of dogs—from beagles to poodles—are maintained by inbreeding. Inbreeding helps to
____________ that the characteristics that make each breed unique will be _________________.
Risks of Inbreeding
• Although inbreeding is useful in retaining a certain set of characteristics, it does have its _________.
– Most of the members of a breed are ___________________ _______________.
– Because of this, there is always a chance that a cross between two individuals will bring together two
recessive alleles for a ________________ ____________.
– _____________________________ in many breeds of dogs, including blindness and joint deformities in
German shepherds and golden retrievers, have resulted from ________________
_____________________.
Increasing Variation
• Selective breeding would be nearly impossible without the wide ________________ that is found in natural
populations.
• This is one of the reasons biologists are interested in preserving the diversity of plants and animals in the wild.
• However, sometimes _______________ want more variation than exists in nature.
• Breeders can increase the genetic variation in a population by inducing ___________________, which are the
ultimate source of genetic ____________________.
Increasing Variation
• As you may recall, mutations are inheritable _______________ in DNA.
• Mutations occur __________________________, but breeders can increase the mutation rate by using
_______________ and ____________________.
• Many mutations are __________________ to the organism.
• With luck and perseverance, however, breeders can produce a few mutants—individuals with mutations—with
_________________ characteristics that are not found in the original population.
Producing New Kinds of Plants
• _____________ that prevent ______________________________________________
during meiosis have been particularly useful in plant breeding.
• Sometimes these drugs produce cells that have double or triple the
normal number of ______________________.
• Plants grown from such cells are called __________________
because they have many sets of chromosomes.
Polyploidy
• Polyploidy is usually ______________ in animals.
• However, for reasons that are not clear, plants are
much better at tolerating ____________ sets of chromosomes.
• Polyploidy may instantly produce new species of plants
that are often ______________and _______________
than their diploid relatives.
Genetic Engineering
• _______________________ - Process of making _____________ in the DNA code of living organisms.
Recombinant DNA
• Recombinant DNA - _______________________________________________________________________
– Can join “synthetic” sequences to “natural” ones using ____________ that splice DNA together.
– Is possible to take a ___________ from one organism and ____________ it to the DNA of another
organism by using enzymes.
Bacteria Transformation
• __________________ - Circular DNA molecule found in bacteria.
– Plasmids are found naturally in some bacteria and are
useful for DNA transfer. Why?
1. It’s DNA sequence _____________ plasmid
________________.
2. Ensures the transformed bacteria will be
replicated.
3. Plasmids contain a __________________
—a gene that makes it possible to __________________
bacteria that carry the plasmid and the foreign DNA from those that don't.
Is it Possible to Transfer Whole Genes From One Organism to Another?
• In 1986, American researcher Steven Howell transferred the gene for luciferase into ____________ plant cells.
1. Luciferase is an enzyme that allows fireflies to ________. The ___________ glowed in the dark!
Transgenic Organisms
• _________________ - Term used to refer to an ____________________________________________________.
1. Transgenic Bacteria
• Reproduce _____________ and are __________ to grow.
• Produce a host of important substances such as ___________, ____________________, and
clotting factor which are used to treat serious human _____________ and conditions.
• Bacteria transformed with the genes for human proteins now produce these important
compounds ____________ and in great ________________.
2. Transgenic Animals
– Used to study __________ and to improve the ____________________________.
• __________ have been produced with human genes that make their immune systems act
similarly to those of humans.
– Allows scientists to study the effects of ________________ on the human immune
system.
• Some transgenic ______________ now have extra copies of growth hormone genes.
– Grow _____________ and produce ____________ meat
3. Transgenic Plants
– Are now an important part of our ___________________.
• In the year 2000, _______% of the ______________ and _______% of the _________ grown in
the US were transgenic, or __________________________ (GM).
• Some GM plants contain genes that produce a natural _________________.
– The crops do not have to be sprayed with synthetic pesticides.
• Other crop plants have genes that enable them to ___________ weed-killing chemicals.
– Allows crops to survive while weeds are still controlled.
Cloning
• Clone - _______________________________________________________________________________
• Cloned colonies of bacteria and other microorganisms are ________ to grow, but this is not always true of
multicellular organisms, especially _________________.
Cloning Animals
• In 1997, Scottish scientist Ian Wilmut stunned biologists by announcing
that he had cloned a ______________, which he later named _____________.
• How did he do it?
1. The ____________ of an egg cell is removed.
2. The cell is _________ with a cell taken from another adult.
3. The fused cell is tricked into thinking it’s fertilized and begins to _____________.
4. The _________________ is then placed in the reproductive system of a foster
surrogate mother, where it develops _________________.
Cloning
• Cloned cows, pigs, mice, and other mammals have been produced by similar techniques.
• Researchers hope that cloning will enable them to make copies of transgenic animals and even help save
_________________________________.
• On the other hand, the technology is ______________________ for many reasons, including studies suggesting
that cloned animals may suffer from a number of __________________________ and
______________________________.
• The use of cloning technology on humans, while scientifically possible, raises serious ______________ and
__________________ issues that have caused many people to ________________ such work. As techniques
improve, these important issues will become even more pressing.
• Clone-