Karyotypes and Gene Technology - mshernandezscience

twoeggfinnishBiotechnology

Dec 14, 2012 (4 years and 10 months ago)

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Karyotypes

and Gene
Technology

How we study Genetics

Karyotypes

1.
Karyotypes
: a photo of the
chromosomes in a dividing cell that
shows chromosomes arranged by
size
.

2. Every person needs
46

chromosomes for normal
development and function.

3. Written in
pairs

of chromosomes (
1
-
22
), the last of which are the Sex
Chromosomes


Karyotypes

4. Too many chromosomes or too few can cause serious
problems


a. May cause extremely short life span

5.
Trisomy

(more than one copy of a chromosome)

a.
Trisomy

21
-

Down’s Syndrome

b.
Increased age during pregnancy increases risk of Down’s
Syndrome


Karyotypes

6. Disjunction: when
chromosomes

of each
homologue
separate

during
meiosis



7. If chromosomes don’t separate
correctly, we call this a
Non
-
Disjunction



a. One gamete gets an


extra chromosome



Down’s Syndrome


Other Methods to Study
Genetics

Recombinant DNA
used to study
Organisms

Restriction Enzymes

Genetic Engineering

Stem Cells

DNA Fingerprinting

Genetic
modifications

Chromosomal
analysis

Electrophoresis

Polymerase chain
reaction

Cloning

Recombinant DNA

8. Recombinant (Recombined!) DNA:
DNA made from 2
or more different organisms

a. Use DNA/RNA Plasmid (circular DNA) and insert
directly into the vector (Bacteria, virus, fungus etc.)


b. Diabetes:

i.
Use Human insulin gene, transfer it to a bacteria.

ii.
Bacteria can transcribe and translate the human gene
using the same code a human cell does to produce
insulin.

Restriction Enzymes

10. Restriction Enzyme: an enzyme that
cuts DNA
molecules at
specific sites

a.
Each strand of DNA has a “sticky end” that can be attached to a new piece of
complementary DNA

b.
This is how recombinant DNA is made

c.
Enzymes are named after the bacteria they are taken from (example:
EcoRI

comes for
E. coli
)

11. Genetic Engineering

a.
Process of manipulating genes for practical purposes.

b.
Think of your favorite fruits. What would you want to change to
make them even better?

o
Bigger

o
Sweeter

o
Redder

o
Juicier

o
Firmer

o
Resistant to pesticides

o
More nutritious


i.
Genetic engineering is a way to make this happen.

c.
Risks? Still highly debated!

12. Stem Cells

a.
These cells can turn into virtually ANY type of human cell.

b.
Embryonic
Stem Cells: from embryos, undifferentiated, and
are
immortal
. These cells really can become ANYTHING in
the human body

i.
Useful for repairing damaged tissues

ii.
Some risk of tumor development from contaminated cell
cultures

iii.
Ethical dilemma

12. Stem Cells

b.
Adult

Stem Cells: come from bone
marrow or the adult brain. These cells
are
not as versatile
as embryonic stem
cells and are not immortal.

i.
Much harder to find

C. Other Ethical Dilemmas: “Playing
God”


12. Stem Cells

12. Stem Cells

13.DNA Fingerprinting

a.
Pattern of dark bands on a
photographic film that’s made
when an individual’s DNA
restriction fragments are separated
by gel electrophoresis, probed and
exposed to an X
-
ray film.

b.
Unique for every individual
(Everyone’s is different)

c.
Requires a certain amount of
DNA

13. DNA Fingerprinting

d. Useful for:

i.
Paternity Tests

ii.
Forensic
science
-

crime
investigations

iii.
Identifying
genetic
disorders like
Huntington’s
diseases and
sickle cell
anemia


14. Genetic Modifications

a.
Genetic
Modications
:
change in the genetic
composition of an
organism through
genetic engineering

b.
Frequently discussed in
terms of food, but the
same concept is also
extended towards
animals

c.
Not OK to do on
people!

15.Chromosomal Analysis

A.

Study of the number and structure of all 46
chromosomes (also called
Karyotypes
)

Highly accurate

Analyzes 15
-
20 cells to determine whether all or just
some cells have normal chromosomes

Geneticists look for thinks like leukemia to determine
the best treatment options, down’s syndrome, missing
sex chromosomes, risk of miscarriages


16. Electrophoresis

A. Separates DNA Fragments when testing for specific gene by
using an electric field

DNA molecules are separated by size on a rectangular gel.

Smaller fragments move faster and farther, forming a pattern
of bands

Specific genes are isolated from these bands by transferring
the fragments in the gel to a filter paper and binding them
to a “probe” that may glow when bound to a gene of
interest.

16. Electrophoresis

17. Polymerase Chain Reaction
(PCR)

a.
Used for small quantities of DNA

b.
Copies small select segments of
DNA to produce up to a
billionfold

of DNA material in a matter of
hours!

c.
Essentially DNA replication in a
test tube

Useful for

Solving crimes

Diagnosing genetic disorders

Studying ancient fragments of
DNA found in fossils or in
preserved materials


18. Cloning

a.
A clone is a
living copy
of an organism.

i.
Monozygotic Twins are clones of each other

ii.
Dolly the Sheep cloned from an adult cell

b.
DNA is a complete copy from another cell and is
injected into an empty nucleus in a
gametic

cell.

a.
Cell division is triggered which can generate a
genetic clone of an organism

c.
The trouble with clones

a.
Very short life span

b.
Medical problems: Bad immune system, fatally
oversized, large chance for developmental
errors

Cloning