Transcript Genetics

Genetics
GENES are more complicated
than Mendel thought
ENVIRONMENT influences the
____________________________
________________________.
expression of genes
“Nature vs Nurture”
= ________________________
provide the ______
plan for
Genes ________
development, but how plan unfolds also
depends on ______________conditions.
environmental
_______
GENES are more complicated
than Mendel thought
Some traits have
choices
____________
MORE than 2 allele __________
MULTIPLE ALLELE TRAIT
= ____________________
EX: blood type
B ___
O
A ___
Allele choices ___
GENES are more complicated
than MENDEL thought
Some traits are determined by
____________________________
MORE THAN ONE GENE
= __________________
POLYGENIC TRAIT
EX: human height,
skin & eye color
GENES are more complicated
than MENDEL thought
Traits determined by ____________
MORE than
ONE
gene have _____
_________
many
“___________”
in-between phenotypes
Genetics of Skin Color
A series of mutations in a gene called
SCL24A5 which controls the size of
melanin packets in skin and the types
of melanin produced
Vitamin D Hypothesis
Bone growth and the body's natural
protection against certain diseases
Inability to absorb enough in areas of
less-powerful sunlight would have
decreased life expectancies in our
African ancestors
Natural Selection!
GENES are more complicated
than MENDEL thought
KINDS OF DOMINANCE
____________________
COMPLETE DOMINANCE
INCOMPLETE DOMINANCE
____________________
CO-DOMINANCE
__________________
COMPLETE DOMINANCE
Dominant allele _______
masks
__________
the ___________
recessive one
PATTERN ?
Recessive allele
____________
________
returns
in a _____ratio
in the
3:1
____
F2 generation
INCOMPLETE DOMINANCE
DON’T
SEE expected
__________
_____
3:1 ratio in
F2 generation
Heterozygous organisms with one
_____________
dominant and one recessive allele
show a _________
BLENDED in-between trait
CO-DOMINANCE
BOTH traits are expressed at ___________
_______
SAME TIME
(_____________________)
in heterozygote
NO BLENDING
A ________HORSE
ROAN
has ______________
BOTH RED hair
WHITE hair side by side.
and __________
CO-DOMINANCE
R= red
W= white
CO-DOMINANCE
Both traits are expressed together
(NO BLENDING) in heterozygote
Persons with an A allele
AND a B allele have
blood type AB
REMEMBER
Membrane proteins with
_______
sugars attached that
help cells recognize self
= ______________
GLYCOPROTEINS
BLOOD TYPES
have more than 2 allele choices
MULTIPLE ALLELE TRAIT
= _________________________
The pattern of sugars that is
attached is determined by genes
Allele choices are:
A
B
O
_____
____
____
BLOOD TYPES
An A allele tells
the cell to put
“A” glycoproteins
on its surface
BLOOD TYPES
A B allele tells
the cell to put a
different “B”
glycoprotein
on its surface
BLOOD TYPES
An O allele tells
the cell NOT to put
anything on the
surface
A and B are CO-DOMINANT
A cell with
BOTH an
A and a B allele
has BOTH
“A” and “B”
glycoproteins on its
surface
BLOOD TYPES & ALLELES
GENOTYPE
AA
AO
BB
BO
OO
AB
PHENOTYPE
(BLOOD TYPE)
A
A
B
B
O
AB
DONOR
BLOOD
A and AB see A
as “like me”
B and O see A
as Different!
IMMUNE SYSTEM
ATTACKS!
DONOR
BLOOD
B and AB see B
as “like me”
A and O see B
as Different!
IMMUNE SYSTEM
ATTACKS!
DONOR
BLOOD
O can donate to
____
EVERY BLOOD TYPE
= _____________________
UNIVERSAL DONOR
Nothing on surface to
recognize as “NOT SELF”
DONOR
BLOOD
Only AB sees AB
as “like me”
A, B, and O see
AB as Different!
IMMUNE SYSTEM
ATTACKS!
AB can only GIVE to AB
BUT . . .
AB can RECEIVE FROM
______
EVERY BLOOD TYPE
= ________________________
UNIVERSAL RECIPIENT
BLOOD TYPE FREQUENCY
IN USA
A
B
AB
O
40%
10%
4%
46%
ABO SYSTEM is NOT
THE ONLY ONE
+
Rh
Rh
OTHER BLOOD TYPES
____________________
IF:
NO PROBLEMS
Rh+
MOM is _____
& BABY is _____
Rh+
MOM is _____
Rh+
& BABY is ____
Rh-
PROBLEM IF:
Can be a ___________
Mom is _____
Rh-
Baby is _____
Rh+
1st baby OK but few baby cells
entering mom’s bloodstream
put mom’s immune system on
alert for + cells.
Next + baby, mom’s immune
system can attack baby as it is
growing
Mom given shot after 1st birth
prevents this
Blood Type Punnett Square
Blood Type Punnett Square
DIHYBRID CROSSES
(2
traits)
Mendel also asked the question?
Does the gene that determines if a seed
is round or wrinkled have anything to
do with the gene for seed shape?
Must a seed that is yellow
also be round?
MAKING A CROSS with
TWO gene traits
___________________=
DIHYBRID
CROSS
____________________
A Punnett square for
a DIHYBRID
CROSS looks like
this:
LAW OF
INDEPENDENT ASSORTMENT
__________________________
the factors are distributed to gametes
independently of other factors
PRACTICE MAKING GAMETES
WHAT ARE THE POSSIBLE GAMETES
THIS PARENT CAN MAKE?
HOMOZYGOUS
ROUND YELLOW
Each gamete should
get one of each kind
of gene
R RYY
R
Y
R
Y
RY
___________ ____________ _____________
RY
_____________
PRACTICE MAKING GAMETES
WHAT ARE THE POSSIBLE GAMETES
THIS PARENT CAN MAKE?
HOMOZYGOUS
WRINKLED GREEN
Each gamete should
get one of each kind
of gene
rryy
r
y
r
y
ry
___________ ____________ _____________
ry
_____________
PRACTICE MAKING GAMETES
WHAT ARE THE POSSIBLE GAMETES
THIS PARENT CAN MAKE?
HETEROZYGOUS
ROUND YELLOW
Each gamete should
get one of each kind
of gene
RrYy
R
Y
r
y
rY
___________ ____________ _____________
Ry
_____________
ry
ry
ry
ry
RY
RrYy
RrYy
RrYy
RrYy
RY
RrYy RrYy
RrYy
RrYy
RY
RrYy
RrYy
RrYy
RrYy
RY
RrYy
RrYy
RrYy
RrYy
RrYy genotype
100% of offspring = _______
ROUND YELLOW phenotype
_______________________
MAKE ANOTHER CROSS
HETEROZYGOUS
ROUND YELLOW
RrYy
X
HETEROZYGOUS
ROUND YELLOW
RrYy
POSSIBLE PARENT GAMETES?
RY
ry
rY
Ry
RY
Ry
rY
ry
RRYY RRYy RrYY RrYy
____
9 Round &
Yellow
Ry
RRYy
3 Round &
____
green
rY
RrYY RrYy
RY
ry
RrYy
RRyy
Rryy
RrYy
Rryy
rrYY rrYy
3 Wrinkled
____
& yellow
rrYy
1 wrinkled
____
& green
rryy
heterozygous dihybrid cross is a
Sign of a ______________________
_____________
9:3:3:1 ratio in offspring.
____
9 ____________
dominant TRAIT 1 ; ____________
dominant TRAIT 2
3 ____________
dominant TRAIT 1; _____________
recessive
____
TRAIT 2
____
TRAIT 2
recessive TRAIT 1; _____________
dominant
3 ____________
____
TRAIT 2
1 ____________
recessive TRAIT 1; _____________
recessive
9:3:3:1
__________ratio
is a clue that it’s a
____________________________cross
HETEROZYGOUS TWO gene
Sex linked traits
Genes that are carried by either sex
chromosome are said to be _________.
sex linked
Sex linked traits
What will happen if there is a recessive
trait on the X chromosome?
Sex linked traits
Examples of X-linked traits:
Red-green color blindness
Male Pattern Baldness
Hemophilia
Duchenne Muscular Dystrophy
Sex linked traits
Can fathers pass recessive X-linked
disorders to their sons?
Pedigree Chart
Pedigree Chart
Building a Pedigree Chart
Inheritance Pattern: normal melanin protein is produced by an
autosomal dominant allele; albinism results from a lack of melanin
and is caused by an autosomal recessive allele.
Use the letter A or a to represent dominant/recessive forms of
albinism.
Two normally-pigmented parents have 3 children. The
first child (a girl) and their second child (a boy) have
normal pigmentation. Their third child (a girl) has
albinism. That girl marries a normally pigmented male
and they have four children. The first three (two girls
and a boy) have normal pigmentation. Their fourth child
(a girl) has albinism like her mother.
Pedigree Chart
What patterns would you expect to see in a
pedigree chart of an:
a.) autosomal dominant trait
b.) autosomal recessive trait
c.) X-linked dominant trait
d.) X-linked recessive trait
e.) Y-linked trait
Autosomal Dominant
Autosomal Recessive
X-linked Dominant
X-linked Recessive
Y-linked
Genetic Disorder Brochure
• What is the disorder?
• How is it inherited (dominant or
recessive/autosomal or sex-linked)?
• What are symptoms?
• What are treatment options?
• What is its frequency among human births?
• Example pedigree of inheritance
Genetic Disorder Brochure
• Examples:
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–
Sickle Cell Anemia
Cystic Fibrosis (CF)
Hemophilia
Huntington’s Disease (HD)