Download Reg Bio DNA tech 2013 ppt

DNA TECHNOLOGY (intro video)


Chapter 16
karyotyping
splicing and restriction enzymes
gel electrophoresis
cloning
stem cells
gene therapy
microarrays
What is a Chromosome?
•STRUCTURE CONTAINING THE
DNA WITHIN A CELL
DNA IS IN THE FORM OF CHROMATIN
IN THE CELL MOST OF THE TIME
(LOOSE FIBERS OF DNA)
USUALLY NOT VISIBLE UNTIL
PREPS FOR REPLICATION –
THEN BECOMES A REPLICAT
ED CHROMOSOME WITH
2 SISTER CHROMATIDS HELD
BY A CENTROMERE
Chromosome Number in Humans









Number of chromosomes in cells?
46 = 23 pairs for humans
23 from mother/23 from father
AUTOMSOMAL chromosomes: 1-22
SEX chrom.: 23rd pair (XX = female / XY = male)
DIPLOID – pairs of chromosomes/2n
23 pairs – total 46
HAPLOID – no pairs /n
23 single
2 kinds of cells

Somatic or Body cells: 2n

Contain diploid # chromosomes
2 sex chromosomes
Pairs of chromosomes

Sex Cells: egg or sperm 1n





Contain haploid # chromosomes
1 sex chromosomes
No pairs of chromosomes
Karyotype
A picture taken through a microscope of a
person’s genome ( chromosomes) organized in
appearance according to size, shape, and banding
appearance. Visible replicated chromosomes
Used for:
Identifying gender
Chromosomal abnormalities
Original photo of nucleus
Male and Female Karyotypes
Male
Female
FYI - Chromosome 1

Chromosome 1 contains nearly twice as many genes
as the average chromosome and makes up 8% of the
human genetic code.

It is packed with 3141 genes and linked to 350
illnesses including cancer, Alzheimer's and
Parkinson's disease

The sequence of chromosome 1 took an international
team of 150 scientists 10 years to complete.
Nondisjunction
Failure of homologous chromosomes to separate
properly during meiosis
Typical Abnormalities:

Trisomy
Gamete with an extra chromosome is fertilized by a
normal gamete, the zygote will have an extra
chromosome
Human-47 Chromosomes instead 46
Extra chromosome #21
Down Syndrome – most common







1. short stature
2. slanting fold of skin of the upper eyelids
3. susceptibility to leukemia and cataracts
4. subnormal mentality
5. shortened lifespan
Chances increase with mother’s age.
But, 23% of cases are due to father having an
extra #21.
Edward’s Syndrome-
2nd most common nondisjunction disorder
trisomy of chromosome 18
 mental and motor retardation
 serious health problems.
Ninety percent die in infancy; however, those
who live past their first birthday usually are quite
healthy thereafter.
They have a characteristic hand appearance
with clenched hands and overlapping fingers.
Other 3 copies of chromosomes:

Three #18

Different symptoms at birth
Both die within a few weeks

Three #13 (Patau)
Nondisjunction
Another example

Triploidy
Total lack of separation of homologous
chromosomes
Offspring with three sets of
chromosomes
 Rare in animals, common
in plants
Triploidy
Abnormalities in Sex Chromosomes

Remember: normal is XX or XY
Turner Syndrome
Monosomy - 1 X chromosome (not XX or XY)
Female
sexual characteristics
are present but underdeveloped.
Sterile, short stature, low
hairline, abnormal eye features
and bone development and a
"caved-in" appearance to the
chest, heart defects
Super Female – XXX, XXXX, XXXXX
XXX – triple X syndrome
 Appearance: normal
 Looks like Turner individual
 Retardation
 Sterile


XXXX, XXXXX – Tetra X and Penta X
severely retarded
Klinefelter’s Syndrome - XXY
Men
are usually sterile, have
longer arms and legs and are
taller than their peers.
Boys with the syndrome are
often shy and quiet, and have a
higher incidence of speech
delay and dyslexia.
Jacob’s Syndrome - XYY

Super male

Taller than average
Persistent acne
Lower intelligence
Criminal Syndrome – early claims incorrect?



What is the diagnosis?
Edward’s
Syndrome
What is the diagnosis?
Kleinfelter’s
(XXY)
Syndrome
What is the diagnosis?
Turner
Syndrome
What is the diagnosis?
Down
Syndrome
Genetic Engineering 
Manipulation and alteration of genes for practical
purposes (use DNA technology)
- identify genes for specific traits
- transfer genes from one organism to another
Terms to Know:

Recombinant DNA:
DNA from 2 or more sources

Transgenic organism:
host organism receiving recombinant DNA
(example: transgenic bacteria can be put into
growth medium to reproduce and make cloned
insulin
GENE SPLICING
Cutting DNA of a gene to add base pairs.
 no sharp instruments are involved,
restriction enzymes are used (like scissors)

DNA ligase “glues the
pieces together!!
Restriction Enzymes




Bacterial enzymes are used to cut DNA molecules
Recognize specific sequences of nucleotides
Create “sticky ends” that can bind to
complimentary chains of DNA
Used to cut DNA samples for DNA fingerprinting
and cloning vectors
DNA Fingerprinting-
pattern of bands made from specific
fragments from individual DNA
Compare banding fragments of two individuals
 Compare two species to see how closely related
 Use a statistical probability of a chance match
between a suspect and biological evidence at a crime
scene or in paternity cases
 Depends upon the number of times a repeating
pattern occurs
Easier to exclude as a parent or convict as criminal

DNA is found in …
hair, semen, blood and other cells
DNA Fingerprinting…
1st used in England for a paternity case in 1985
1st used in U.S. to convict criminals in 1987
Accuracy





Complete sets of DNA are not compared
Only .1% of human genome varies from person to
person (ID people by this DNA)
Useful for: person’s paternity, identifying human
remains, tracing human origins, and providing
evidence in a criminal case.
98% of genetic makeup doesn’t code for proteins
Compare segments that vary the most from person
to person (noncoding segments that repeat over
and over)
More uses for DNA Fingerprinting?





Identify endangered and protected species as an aid to
wildlife officials (could be used for prosecuting
poachers)
Detect bacteria and other organisms that may pollute
air, water, soil, and food
Match organ donors with recipients in transplant
programs
Determine pedigree for seed or livestock breeds
Authenticate consumables such as caviar and wine

The likelihood that any 2 people
would share the same DNA
profile is…
1 in a quintillion (18 0’s)
How is a DNA fingerprint made?

1) Restriction enzymes are added to the DNA sample to cut
it up into smaller pieces or fragments
How is a DNA fingerprint made?

2) Fragments are pulled through a gel (by an
electrical charge) and distribute according to
the size of the fragment
How is a DNA fingerprint made?

3) An x-ray picture is
taken of this distribution
and then can be
compared to other DNA
samples
How is a DNA Fingerprint made?

Different people have
different restriction
enzyme “cut sites”
Person 1 Person 2
Resulting in different sized
DNA fragments.
Resulting in different band patterns
on a gel
Uses of….
Video: Can We Live Forever?
PBS

53 minutes