Transcript DNAvariationmutationetc

5.2
 Differences
or variation in DNA are what makes
us different from each other!
 Each

human cell contains 46 chromosomes
Each cell has 3 billion base pairs of DNA (wow!)
 Our
 Of
DNA is 99.99% similar
the 6 billion base pairs of DNA, only 5% are
in the genes that code for RNA and proteins.
.
 Errors
can occur when DNA is copied
 UV light, X-rays, chemicals, etc. affect DNA
Substitution
– Exchanges one base
for another.
 CTGGAG---- CTGGGG

Insertion – Extra base pairs are
inserted.
 CTGGAG---- CTGGTGGAG
Deletion-
Section is lost, or
deleted.
 CTGGAG -----CTAG
Frameshift-
Message is no longer
read correctly.
 THE
FAT CAT SAT --- HEF ATC ATS AT
 Cells
have different ways to repair mistakes
 Certain enzymes can proofread DNA such as
correcting mismatched base pairs
The mutation causes no effect.
1.
1.
2.
Amino acids have more than 1 code
Enough protein may be produced already
The effect of a mutation is minor.
2.
1.
Could affect skin/eye/hair pigmentation
The effect of a mutation is great.
3.
1.
Genetic disorder/disease
 Sometimes
passed from parents to offspring
 Sickle Cell Anemia
 Cystic Fibrosis (CF)
 Hemophilia
 Tay- Sachs Disease
 Huntington’s Disease (HD)
 Hypercholesterolemia
 Cancer
 People




Alzheimer's
Emphysema
Diabetes
Cancer
 Their

can carry a tendency for a disease.
behavior can prevent it:
Not smoking can prevent emphysema and many types of
cancer
 Most
genetic disorders cannot be cured, although
progress is being made.
 Families
who have a history of genetic disorders
are recommended to undergo counseling before
having a child. They can find out how it could
affect their offspring.
 Some
genetic disorders can be treated if diagnosed
early enough, such as PKU (lacking a certain
enzyme).

If known, that child can be put on a certain diet and
medicine routine.
 Mutation
occurs on gene that
codes for hemoglobin

Hemoglobin – a protein that
carries oxygen in red blood
cells
 Mutation
causes 1 amino acid
to be replaced with another
 Need
2 recessive
genes to be affected
(ss)
 Can
be a carrier (Ss)
5.3
 Random
changes in
DNA can introduce
new traits in an
organism
 Humans can breed
animals to get the
certain traits they
want.

Ex: a cow that gives
more quantities of milk
Bloodhound – strong sense of smell
The process of
selecting and
breeding parent
organisms to pass on
particular traits to the
offspring.
A
sequence of DNA from an organism is first
isolated, then inserted into the DNA of another
organism.
 The
DNA inserted usually codes for a particular
trait of interest
 GMO
– Genetically modified
organism
 Can
make plants
more insect
resistant.
 Create
crops
suitable for areas
with poor soil
conditions
Food can be resistant
to certain bacteria
and pests.
 Reduces chemical
pesticides
 Increases food
production
 Add nutrients

PROS
Possibly harmful to
the human body but
still unknown
 Could risk wild
population like
salmon

CONS
 Can
be used to produce new and better drugs
for treating disease
 Determine the side effects of a drug on an
individual
 Can be used to screen for and treat genetic
disorders

May soon allow scientists to correct certain recessive genetic disorders
by replacing defective genes with copies of a healthy one.

First step of gene therapy is to isolate a copy of the gene.

Scientists are trying to input that gene into the cell by attaching it to a
cold virus. Attempts in humans have not been successful.

However, the outlook is promising.
 Crime
scenes –
skin, hair, blood
 DNA
profile – a
DNA fingerprint
 Everyone
different
except identical
twins!
 All
the genetic material in an organism.
 The
human genome project wanted to
sequence all of the human genome (that’s a
lot)
 We

can then compare DNA across species
We have similar genes to fruit flies and mice
A
technique that
uses technology to
make copies.
 Can be applied to
a segment of DNA
or a whole
organism
Dolly 
 Place
gene that
codes for producing
insulin
 That
bacteria then
replicates in large
numbers
 Treats
people with
diabetes