Human Genome & Genetic Engineering - 2009.pptx

triteritzyΒιοτεχνολογία

14 Δεκ 2012 (πριν από 4 χρόνια και 10 μήνες)

174 εμφανίσεις

The Human Genome
 
& Genetic Engineering
Chapter 13 & 14
Karyotyping
n
Human Chromsomes
q
Karyotype- picture of arranged
chromosomes
q
Humans have 46 chromosomes
q
There are 44 (22 pairs) of
autosomes
q
There are 2 sex chromosomes
q
All egg cells carry an X
chromsome, no Y. Half of a
male’s sperm contain an X and
the other half contain a Y.
Human Karyotype
Pedigrees
n
Human Traits
q
Pedigree- chart that shows relationships in a
family
q
Some traits cannot be followed on a pedigree
n
They are polygenic
n
Many traits are influenced by the
environment, nutrition, and exercise
Human Pedigrees
A circle
represents a
female.
A square
represents a male.
A horizontal line
connecting a male and
female represents a
marriage.
A vertical line and a
bracket connect the
parents to their
children.
A half-shaded
circle or square
indicates that a
person is a carrier
of the trait.
A completely
shaded circle
or square
indicates that a
person
expresses the
trait.
A circle or square
that is not shaded
indicates that a
person neither
expresses the
trait nor is a
carrier of the trait.
Pedigree Construction
Human Genes ­ Autosomal 
Recessive Allele Disorders
q
q
Albinism- lack of pigment in skin, hair, eyes
q
Cystic Fibrosis- excess mucus in lungs,
digestive tract, liver, increased infection
q
Galactosemia- accumulation of galactose in
tissues, mental retardation, eye and liver
damage
q
PKU- lack the enzyme needed to break
down phenylalanine
q
Tay-Sachs- nervous system break down
q
Human Genes ­ Autosomal 
Dominant Allele Disorders
 
q
q
q
Achondroplasia- dwarfism
q
q
Huntington’s- mental retardation and
uncontrollable movements; symptoms
usually appear in middle ag
e
n
Human Genes – Autosomal 
Codominant Allele Disorders
q
Sickle-cell anemia
n
Sickled red blood cell, cannot carry
oxygen efficiently
n
Only one DNA base is changed to
produce this disease
n
Heterozygous for Sickle cell are
healthier because they have some
normal hemoglobin (they are also
resistant to malaria)
n
Human Genes ­ Sex linked Allele 
Disorders
 
q
Males have just one X chromosome. All X-
linked alleles are expressed in males, even if
they are recessive.
q
Disorders are more common in males
n
Colorblindness- inabililty to detect distinguish
certain colors
n
Hemophilia- lack certain protein for blood clotting
so can bleed to death
n
Duchenne Muscular Distrophy- weakening and
loss of skeletal muscle
Blood Typing
n
Human Blood Groups
q
A(I
A
I
A
or I
A
i)
q
B(I
B
I
B
or I
B
i)
q
AB(I
A
I
B
)
q
O(ii)
q
Phenotype
(Blood Type
Genotype
Antigen on
Red Blood Cell
Safe Transfusions
To
From
Human Blood Groups 
DNA Analysis
n
Scientists perform genetic tests for DNA
sequences found in the alleles to determine
if a person has the disorder
n
The testing is done if both parents are known
to carry the trait
DNA Fingerprinting
n
Analyzes DNA fragments
n
No 2 individuals’ DNA are alike except for
identical twins
n
Started in the late 1980’s in criminal cases
Human Genome Project

n
An ongoing effort to analyze the human DNA
sequence, which contains over 6 billion
base pairs
n
n
In 2000, scientists announced the project (for
the most part) was complete
n
How did they do it?
n
Scientists cut the DNA into fragments and
determined the sequence of each fragment
n
They used computers to put the fragments
together by overlapping areas, then they
aligned these fragments with the known
markers on the chromosome
Gene Therapy
n
Scientists must first identify a faulty gene
n
n
The absent or faulty gene is replaced with a
normal working gene
n
n
If successful, the body then starts producing
the correct gene
Selective Breeding
n
Humans use selective breeding, which
takes advantage of naturally
occurring genetic variation in plants,
animals, and other organisms, to
pass desired traits on to the next
generation of organisms.
n
Just about all domesticated animals
and most crops have been created
by selective breeding.
n
Ex. Navel oranges, shasta daisies,
several varieties of tomatoes
n
Luther Burbank was the greatest
selective breeder of all time
Hybridization
n
Type of Selective
Breeding
n
Crossing dissimilar
individuals to bring
together the best of
both organisms.
n
Offspring are hardier
than parents.
n
Liger, dog wolf, iron
age pig, wolphin,
zeriod
Inbreeding
n
Type of selective breeding
n
The continued breeding of individuals with
similar characteristics.
n
Helps to ensure that the traits that make each
breed unique are preserved.
n
Greater chance that a cross between two
individuals will bring together two recessive
alleles for a genetic defect.
Increasing Variation
n
Breeders can increase the genetic variation
in a population by inducing mutation, which
are the ultimate source of genetic
variability.
n
Producing new kinds of bacteria. Example-
oil digesting bacteria
n
Producing new kinds of plants. Polyploidy
plants are larger and stronger than their
diploid relatives.
Manipulating DNA
n
Scientists use their knowledge of the
structure of DNA and its chemical
properties to study and change DNA
molecules.
n
Different techniques are used to extract DNA
from cells, to cut DNA into smaller pieces,
to identify the sequence of bases in a DNA
molecule, and to make unlimited copies of
DNA.
Transgenic Organisms
n
Contain genes from other species
q
Bacteria- produces insulin, growth hormone,
clotting factor
q
Animals- faster leaner meat in animals, resist
disease and bacteria
q
Plants- contain a natural pesticide, may
produce human antibodies that can be used
to fight disease, contain vitamins
Gel Electrophoresis
n
A mixture of DNA fragments are placed in a
well
n
Electricity is applied to the gel and the DNA
moves from one side to the other
n
The smaller the fragment, the faster and
further it moves
Gel Electrophoresis
DNA plus
restriction enzyme
Mixture of DNA
fragments
Gel
Power
source
Longer
fragments
Shorter
fragments
Reading the sequence