Transcript Chromosome Disorders

Genetic Disorders,
Blood Typing, and
Genetic Engineering
Genetic Disorder
Is an abnormal condition that a person inherits
through genes and chromosomes
Two causes:
Mutations in DNA
Changes in overall structure or numbers of chromosomes
Prenatal Diagnosis
Amniocentesis
A small sample of the amniotic fluid surrounding the
baby is removed using a syringe.
The fluid contains skin cells from the baby.
The skin cells are grown in the lab.
The chromosomes from the cells are magnified under
a microscope and a picture is taken.
The chromosomes are cut out and arranged in
homologous pairs in decreasing size order.
This is called a karyotype.
Down Syndrome
(Trisomy 21)
Extra chromosome 21 in
every cell of the body
Causes mental retardation, heart defects
As a woman gets older, her chances of having a baby
with a chromosome abnormality increases
***remember, a woman is born with all of her egg cells,
but meiosis is not yet complete
(egg development stops in prophase I until the follicle
matures prior to ovulation)
Turner Syndrome
female born with only one X chromosome
Characteristics
short stature
ovaries do not develop (infertile)
cardiovascular problems
kidney and thyroid problems
skeletal disorders such as scoliosis
Klinefelter Syndrome
47,XXY
Characteristics
Infertility (cannot produce a lot of sperm)
Abnormal body proportions (long legs, short trunk,
shoulder equal to hip size)
Abnormally large breasts (gynecomastia)
Cystic Fibrosis
Genetic disorder in which the body produces
abnormally thick mucus in the lungs and intestines
Caused by a recessive allele that is a result of a
mutation in which 3 bases are deleted from a DNA
molecule
Sickle Cell Disease
Affects hemoglobin, which is a protein that carries oxygen
When oxygen levels are low the blood cells have a sickle shape
instead of the normal round shape
These sickle shaped blood cells clog blood vessels and carry less
oxygen
Autosomal recessive
How to Manage Genetic
Disorders
Karyotypes – used to detect chromosomal disorders
such as down syndrome
Genetic counseling -Assess the risk of a genetic
disorder by researching a family's history and
evaluating medical records.
Blood Typing
controlled by multiple alleles
Human trait controlled by more than one allele is said
to have multiple alleles
Even though a gene may have multiple alleles, a
person can only carry 2 of those alleles because we
have only 2 chromosomes
Four major blood types: A, B, AB, AND O
ALLELES FOR BLOOD TYPES
A
B
O
Blood types A and B and
AB
Codominant
Alleles for blood type A is AA
Alleles for blood type B is BB
a cross between blood type A and blood type B
Results in a person with type AB blood
Blood Type O
TYPE O
BLOOD
Allele for blood type O is recessive
Only way to get blood type O is to have both parents
with blood type O
Oh, the possibilities!
ALLELE FROM
PARENT 1
ALLELE FROM
PARENT 2
GENOTYPE
BLOOD TYPE
A
A
AA
A
A
B
AB
AB
A
O
AO
A
B
A
AB
AB
B
B
BB
B
B
O
BO
B
O
O
OO
O
Advances in Genetics
Human Genome Project
DNA fingerprinting
Genetic engineering
Human Genome Project
(HGP)
Genome is all the DNA in one cell of an organism
HGP- is the code that is 6 billion letters long
Main goal of the project is to identify the DNA
sequence of every gene in the human genome
We have at least 30,000 genes
Average gene has about 3000 bases
DNA Fingerprinting
DNA is broken down into
small fragments
Selected fragments rare
used to produce a pattern
called: DNA FINGERPRINT
Except for identical twins
no 2 people have the same
DNA fingerprint
Genetic Engineering
Genes from one organism are transferred into DNA
of another
Used to produce medicine and crops resistant to
diseases
Insulin (used by diabetics) is produced by genetically
engineered bacteria
Genetic Engineering of
Organisms
Genes are inserted into animals such as cows to
produce the human clotting protein needed by
people with hemophilia
Spider Goat