Download Genetic Technology

Genetic
Technology
Applied Genetics
• Selective breeding - produces organisms
with desired traits.
1.
2.
Takes time, patience and several generations.
Increases the frequency of desired alleles.
• Inbreeding –
develops pure lines.
1.
2.
3.
Mating closely
related individuals.
Results in offspring
that are homozygous
for most traits.
Inbreeding can bring
out harmful,
recessive traits
because there is a
greater chance that
two closely related
individuals both may
carry a harmful
recessive allele for
the trait.
Click inside box to play movie
Hybrids
• Hybridization –
crossing parents with
different forms of a
trait.
a. Plants produced
from crossing two
cultivars often bigger
and better.
b. Animals – when
two species are
crossed sterile hybrids
are produced.
Zorse –
cross
between a
horse and
a zebra.
Determining Genotype
• A test cross is done to
determine the genotype of
an unknown dominant
individual.
1. A dominant phenotype
can be homozygous or
heterozygous.
2. Cross the unknown to
a homozygous
recessive. If any of
the offspring are
recessive, you know
the unknown is
heterozygous.
Unknown
Homozygous
recessive dd
Unknown is DD
Unknown is Dd
Click inside box to play movie
Recombinant DNA Technology
• Genetic engineering – a faster and more reliable
method for increasing the frequency of a specific
allele in a population.
• Recombinant DNA – made by connecting or
recombining fragments of DNA from different
sources.
Transgenic Organisms
• Organisms that contain
foreign DNA.
• Achieved by a three step
process:
1. Restriction enzymes
cut, or cleave the
DNA.
A. If the same
enzyme is used to
cleave
DNA in two different
organisms, the
DNA pieces will tend
to stick together.
B.“Sticky ends” are
key to recombinant
DNA.
Click inside box to play movie
C. Gel electrophoresis is used to separate the DNA
pieces cut with restriction enzymes.
The
Electrical
Field
Filling the wells
Fragments
move
2. Vectors transfer DNA
to a host cell.
A. Biological =
viruses and
plasmids.
B. Mechanical =
micropipettes and
gene guns.
Click in box to play movie
3. DNA is rejoined by gene splicing.
A. Transferred to the host by one of the vectors.
B. Duplicates as the host cell divides.
Polymerase Chain Reaction (PCR)
• Method of replicating
DNA outside of living
organisms.
• Essential for analysis
of DNA.
• Has allowed
molecular genetics to
become part of
criminal
investigations.
Click in box to play movie
Applications of DNA Technology
• Cloning of organisms, as well as genes.
• Pure DNA for study of specific genes from
PCR.
• Recombinant bacteria.
a. industrial use – break down pollutants.
b. medical use – produce hormones, insulin or.
amino acids.
c. used in agriculture to prevent frost on crops.
• Transgenic animals – scientists can create
animals with human diseases and animals that can
produce human materials.
• Transgenic plants –
have been engineered
to resist herbicides,
produce internal
pesticides and
increase their protein
production.
Click in box to play movie
Human Genome
• The Human Genome
Project – has mapped
and sequenced all
human genes.
A. We have a linkage
map.
1. 35 - 40,000 genes
on 46
chromosomes.
2. We know where
the genes are
located, but do
not know the
function of all
genes.
Applications of the Human Genome
Project
• Diagnosis of
genetic disorders
followed by gene
therapy.
A. Insertion of normal
genes into human
cells to correct
genetic disorders.
B. fetal diagnosis
and therapy.
• DNA Fingerprinting – no two individuals have the
same DNA fingerprint, except identical twins.
A. Criminal investigations.
B. Identification of family members, dead or alive.