Transcript CAUSE - Cloudfront.net

Inheritance Patterns and
Human Genetics
Chapter 12-1 & 12-2
The sequence of A’s, T’s, G’s & C’s
ORDER of amino
acids in
tells the _______
________
the ________
protein
Changes in the gene code
_______________
change the protein that is made
A change in the genetic code =
MUTATION
________________
KINDS OF MUTATIONS
SOMATIC CELLS
BODY
________
CELLS = ___________
Somatic cell mutations can:
______________________
Cause cancer
Make cell not able to function
______________________
_____________
Kill cell
WON’T BE passed on to offspring
BUT _________
Kinds of Mutations
GAMETES
___________
(sperm & eggs)
GERM
= _________cells
CAN BE passed
 Germ cell mutations ________
on to offspring
http://anthro.palomar.edu/biobasis/images/meiosis.gif
MUTATIONS can be:
____________
HARMFUL - Mutations that produce
defective
proteins are usually harmful.
______________
Harmful mutations are associated with many
genetic disorders and can cause
________________
____________
cancer
MUTATIONS can be:
____________
- Some mutations
LETHAL
change proteins that are so vital to life
that they cause death, usually before
birth.
KINDS OF MUTATIONS
Mutations that produce changes
in a single gene =
GENE MUTATIONS
_________________
Mutations that produce changes
in whole chromosomes =
CHROMOSOMAL
MUTATIONS
_____________________
GENE MUTATIONS
Mutations involving ________________
One or a few
____________
= __________________
nucleotides
Point mutation
because they occur at a single point in the
DNA sequence.
TYPES OF POINT MUTATIONS:
_____________________
substitutions
deletions
_____________________
insertions
_____________________
SUBSTITUTION
Changes one base for another
ATTCGAGCT
ATTCTAGCT
How many amino acids get changed?
DELETION
Piece of DNA code is lost
ATTCGAGCT
ATTCAGCT
How many amino acids get changed?
INSERTION
Extra piece of DNA is added
ATTCGAGCT
ATTCGCAGCT
How many amino acids get changed?
GENE MUTATIONS
Substitutions usually affect no more than a
Amino acid
single ____________,
but deletions and
insertions can have a more dramatic effect.
IMAGE FROM BIOLOGY by Miller and Levine; Prentice Hall Publishing©2006
FRAME SHIFT MUTATIONS
Change multiple bases in code
thefatcatatetherat
the fat cat ate the rat
____________________
INSERTION
thefatcataatetherat
the fat cat aat eth era t
DELETION
thefatcatatetherat
the fat ata tet her at
FRAME SHIFTS
Frame shift mutations change every
Amino acid
___________
in the ___________
protein
that follows the shift.
Frame shifts can alter a protein so
function
much it is unable to _____________
Location of the shift is important!
AT BEGINNING
the fat cat ate the rat
the fac ata tet her at
AT END
the fat cat ate the rat
the fat cat ate thr at
BEGINNING
MUTATIONS AT _____________OF
GENE
DAMAGE __________
OF THE CODE!
MORE
CHROMOSOMAL MUTATIONS
Mutations involving changes in the
Number
structure
_____________
or ______________
of whole chromosomes
TYPES OF CHROMOSOMAL MUTATIONS:
_____________________
deletions
duplications
_____________________
inversions
_____________________
translocations
_____________________
DELETION
Piece of chromosome is lost
________________________________________
DUPLICATION
Piece
of DNA is copied too many times
________________________________________________
INVERSION
Segment flips and reads backwards
TRANSLOCATION
Segment breaks off and joins a
different non-homologous
chromosome
POLYPLOIDY
Condition in which an organism has
extra sets of chromosomes
POLYPLOIDY
= _______________
LETHAL
__________
in humans, but beneficial
in some ___________.
plants
A mutation that causes a protein to be
NON-FUNCTIONAL would appear
RECESSIVE
_______________
to the normal working allele.
AUTOSOMAL RECESSIVE
Examples of __________________________
GENETIC DISORDERS:
PHENYLKETONURIA
(PKU)
____________________
TAY-SACHS DISEASE
____________________
CYSTIC FIBROSIS
____________________
Phenylketonuria (PKU)
CAUSE:
ENZYME
Mutation in gene for an ___________
that __________
called
breaks down an ___________
amino acid
phenylalanine
X
X
MENTAL RETARDATION
Build up causes ________________________
http://biology.clc.uc.edu/courses/bio104/protein.htm
TAY-SACHS DISEASE
AUTOSOMAL RECESSIVE
___________________
CAUSE:
Mutation in gene for an ___________
ENZYME that
breaks down a kind of _________in
the
LIPID
developing _________
BRAIN
Build up of lipids in brain cells leads to:
mental retardation, blindness, and DEATH
in early childhood
heterozygous person
A __________
who carries a
recessive allele for a
_________
genetic disorder, but
doesn’t show
______________
the
disorder themselves
is called a
CARRIER
_____________
http://www.biochem.arizona.edu/classes/bioc460/spring/rlm/RLM36.1.html
CYSTIC FIBROSIS
CAUSE:
Loss of 3 DNA bases in a gene for the
_____________
that transports _________
so
protein
Cl- ions
salt balance is upset
thick mucous
Causes a build up of _________________
in lungs
and digestive organs
Image from: BIOLOGY by Miller and Levine; Prentice Hall Publishing ©2006
CYSTIC FIBROSIS
http://learn.genetics.utah.edu/content/disorders/whataregd/cf/index.html
CYSTIC FIBROSIS
Leads to:
_________ and _________
respiratory
digestive complications,
increased susceptibility to infections;
Salty skin is a symptom
“__________”
30,000 people in U.S. have cystic fibrosis
1 in 31 people are carriers
A mutation that codes for a new protein
whose action masks the normal allele
appears as a ______________
DOMINANT mutation.
AUTOSOMAL DOMINANT
Examples of _________________________
GENETIC DISORDERS:
Huntington’s disease
____________________
Achondroplasia
____________________
HUNTINGTON’S DISEASE
AUTOSOMAL DOMINANT
______________________
CAUSE:
CAG repeats at end of gene
Extra 40-100 ______________
on chromosome 4
more repeats . . . the more __________
severe
The _____________
the symptoms.
http://www.healthsystem.virginia.edu/internet/huntdisease/images/cag.gif
HUNTINGTON’S DISEASE
Huntington’s brain
loss
Causes progressive _____
muscle control
of ________________
and
mental
___________function
1 in 10,000 people in U.S.
have Huntington’s disease
Normal brain
http://www.scielo.br/img/revistas/bjmbr/v39n8/html/6233i01.htm
A person with
Huntington’s disease
50% chance of
has a _____
passing the disorder on to
their offspring.
Problem:
Symptoms of disorder usually don’t show
until ____________
MIDDLE AGE . . .
so you don’t know you have it until
________
AFTER you have had children.
ACHONDROPLASIA
(One kind of Dwarfism)
AUTOSOMAL DOMINANT
CAUSE: ___________________________
gene
1 in 20,000 births
ACHONDROPLASIA
(One kind of Dwarfism)
Normal size head and
torso; short arms and legs
Problem with way cartilage
changes to bone as bones
grow
DISORDERS CAUSED
AUTOSOMAL CODOMINANT ALLELES
BY ____________________
SICKLE CELL DISEASE
____________________
CAUSE:
A changed to T
in gene for
HEMOGLOBIN
__________________
(protein in red blood cells
that carries oxygen in blood)
SICKLE CELL DISEASE
SYMPTOMS:
RED BLOOD CELLS become sickle
_____________
TWO
shaped in persons with ______
ALLELES
sickle cell ________
A person who is __________________
for
HOMOZYGOUS
the ____________allele
(ss) will have
sickle cell
_______________
sickle disease
HOMOZYGOUS
A person who is _________________
for
normal hemoglobin alleles will have normal
blood cells, but can become infected with
malaria
__________
(SS)
HETEROZYGOUS person (Ss)
A _________________
(with one normal/one sickle cell allele) is
generally healthy and has the benefit of
resistant to malaria
being _________
Chromosomes that determine
the sex of an organism =
_________________
Sex chromosomes
http://www.angelbabygifts.com/
All other chromosomes =
_________________
autosomes
Humans have two sex chromosomes
X
y
and _____
44 autosomes
SEX DETERMINATION
XX = female
Xy = male
Who decides?
Mom can give X
Dad can give
X or y
X
X
X
XX
XX
y
Xy
Xy
Dad determines sex of the baby.
SO ____
If dad gives X with mom’s X = girl
If dad give y with mom’s X = boy
PEDIGREES
_______________are
diagrams
genes are passed
that show how are ____________
in families
on __________
over several
generations
Drawing a pedigree chart
SEX CHROMOSOMES
CAN CARRY OTHER
GENES TOO
= ___________________
SEX LINKED TRAITS
These traits show up in different
_______________
in males and females
percentages
because they move with the sex
chromosomes
Y-LINKED GENES:
carried on Y
Genes ______________
chromosome
EXAMPLE:
Hairy pinna
ONLY show up _______
in males
Y linked
_________genes
_____
X-LINKED GENES:
____________
are carried on the X chromosome
X-linked recessive disorders
MORE frequently
show up _____________
in MALES
______ than females
because males only have
ONE X chromosome.
______
Males ONLY HAVE ONE X
DEFECTIVE
They either
have the
disorder
NORMAL
Or
They are
normal
FEMALES HAVE TWO X CHROMOSOMES
DEFECTIVE
NORMAL
DEFECTIVE
Females have
one normal
gene that works.
need 2
Females __________
defective recessive
alleles to show the
disorder
X-LINKED RECESSIVE
Examples of ________________________
DISORDERS:
HEMOPHILIA
____________________
COLORBLINDNESS
____________________
DUCHENNE MUSCULAR DYSTROPHY
____________________
HEMOPHILIA
CAUSE:
Mutation in genes for __________________
Blood clotting proteins
on X chromosome
carried ______
Blood clotting proteins are missing so person
with this disorder can’t stop bleeding when
bleed to death from minor
injured; can ________________
cuts or suffer internal bleeding
from bruises or bumps.
COLORBLINDNESS
CAUSE:
Mutation in one of three genes for
_______________
carried on X chromosome
Color vision
Persons with this disorder have trouble
distinguishing colors.
Red-green
_________________
colorblindness is most common
Seen in 1 in 10 males
1 in 100 females
http://gizmodo.com/gadgets/peripherals/samsung-develops-lcd-for-colorblind-036306.php
What’s the pattern:
Y-linked traits show up _______
ONLY in _______
males
________
X-linked recessive traits:
__________________
______________________
more common in males than females.
________________
ONLY FEMALES can be ________.
carriers
AUTOSOMAL RECESSIVE traits:
_______________________
FEMALES can be ________
carriers
BOTH MALES
______ & _________
CHROMOSOMAL MUTATIONS
____________________________:
structure or
Change in the ______________
number
____________
of chromosomes
Homologous chromosomes
fail to separate during MEIOSIS
________________
NONDISJUNCTION
= _________________________
One cell gets 2 copies of
the chromosome the
other cell gets none.
Nondisjunction
Nondisjunction
Since it happens to a
sperm or egg, the new
baby can end up
3 copies
with _____________
of a
chromosome
TRISOMY
= __________________
OR
one copy of a
only ___________
chromosome
= ___________________
MONOSOMY
TRISOMY 21
Down syndrome (= ____________)
Down syndrome (Trisomy 21)
• 1 in 800 births
• Similar facial
features
• Slanted eyes
• Protruding tongue
Down syndrome (Trisomy 21)
• Most common chromosomal
abnormality
• 50% have heart defects that
need surgery to repair
• Mild to severe mental
retardation
• Increases susceptibility to
many diseases
• Risk of having a child with
Down syndrome increases
with age of mom
Klinefelter syndrome
• 1 in 1000 births
• Males have extra X chromosomes
(Can be XXy, XXXy, or XXXXy)
• Average to slight decrease in intelligence
• Small testes/can’t have children
• Usually not discovered until puberty when
don’t mature like peers