SEX-LINKED
and
SEX
INFLUENCED
TRAITS
SEX DETERMINATION
XX = female
Xy = male
Who decides?
X
X
X
Mom can give X
X
Dad can give X or y
y Xy
Dads determine sex of babies.
If dad gives X with mom’s X = girl
If dad give y with mom’s X = boy
X
XX
Xy
SEX CHROMOSOMES
CAN CARRY OTHER
GENES TOO
SEX LINKED TRAITS
= ___________________
show up
in different % in males and
females because they move with
the sex chromosomes
SEX LINKED TRAITS
Sex chromosomes can
carry other genes
Y-LINKED GENES:
Genes carried on Y chromosome
EX:
Hairy pinna
Y linked
males.
_________genes
only show up in _______
Make a cross with a y-linked gene
Hairy ears is a
Y linked
________________
dominant
________________
trait
H for hairy ears.
Use ______
Use ______
h for recessive normal ears.
H
y
On y chromosome so write it as ________
Make a cross with a y-linked gene
X
X
H
y
XX
X yH
X
XX
X
H
y
ALL GIRLS =
____________
Normal ears
ALL BOYS =
Hairy ears
____________
Sex chromosomes can
carry other genes
X-LINKED GENES:
Genes carried on
the X chromosome
EX: _____________
Hemophilia
_____________
Colorblindness
Duchenne Muscular Dystrophy
_________________________
Make a cross with an X-linked gene
Hemophilia is an
X-linked
________________
recessive
________________
disease
H for normal dominant blood
Use ______
clotting gene.
h
Use ______
for recessive hemophilia gene.
h
X
On X chromosome so write it as ________
Mother
H H
Without hemophilia = X X
H
Without hemophilia = X X
h
h
With hemophilia = X X
Father
H
Without hemophilia = X y
h
With hemophilia = X y
h
CARRIER
Make a cross with an X-linked gene
H
X
H
X
h
X
H
y
X X
H
X X
y
Carrier Mom X
Normal dad
H
h
H
X y
X
h
GIRLS
1/2 = normal
_______
_______
1/2 = look normal
but are
CARRIERS
BOYS
1/2 = normal
_______
_______
1/2 = hemophilia
Make a cross with an X-linked gene
Colorblindness is an
X-linked
________________
recessive
________________
disease
B for normal dominant color gene
Use ______
b
Use ______
for recessive colorblind gene.
b
X
On X chromosome so write it as ________
Mother
B
B
normal vision = X X
B
normal vision = X X
b
b
colorblind = X X
Father
B
normal vision = X y
b
colorblind = X y
b
CARRIER
Color blindness is sex linked
y
Xb
X
B
X
B
B
X X
b
XBXb
XBy
XBy
GIRLS = _______________
100% carriers
100% normal
BOYS = ________________
HOMOZYGOUS
Normal Mom X
colorblind dad
SEX LINKED TRAITS show
up
in different % in males and
females because they move with
the sex chromosomes
ONLY show up in males.
Y linked genes ________
more often
X linked recessive genes appear __________
in males than females.
CARRIERS for X linked
Females can be __________
recessive traits.
NEVER BE carriers for X linked
Males can _________
recessive genes. The either have trait OR are
normal.
SEX INFLUENCED
TRAITS
not carried on sex
Genes ___________
chromosomes BUT affected by
____________
sex hormones of individual with
gene
Male Pattern Baldness
Autosomal
dominant gene
YOUR SEX CHANGES THE
EXPRESSION OF THE GENE
B is dominant for baldness
B’ is recessive for not bald
If you are MALE:
BB = BALD
BB’ = BALD
B’B’ = NOT bald
If you are FEMALE:
BB= BALD
BB’= NOT bald
B’B’= NOT bald
Will they be bald?
Bald = B
BX
B’X
B’X
XXBB’
XXBB’
By
XyBB’
XyBB’
Girls: 100% NOT BALD
Autosomal
Dominant gene
Bald dad X
pure non bald mom
Boys: 100% BALD
Will they be bald?
Bald = B
B’X
BX
B’X
XXBB’
XXB’B’
B’y
XyBB’
XyB’B’
Girls: 100% NOT BALD
Autosomal
Dominant gene
NOT BALD dad X
NOT BALD mom
(who had a bald dad)
Boys: 50% BALD
50% NOT BALD
How are genes passed on over
generations?
PEDIGREE
CHART
Males =
Females =
Has trait =
Carrier =
SEX-LINKED
and
SEX
INFLUENCED
TRAITS
SEX DETERMINATION
XX = ___________
Xy = _________
Who decides?
X
Mom can give X
X
Dad can give X or y
y
Dads determine sex of babies.
If dad gives X with mom’s X = girl
If dad give y with mom’s X = boy
X
SEX CHROMOSOMES
CAN CARRY OTHER
GENES TOO
= ___________________
show up
in different % in males and
females because they move with
the sex chromosomes
SEX LINKED TRAITS
Sex chromosomes can
carry other genes
Y-LINKED GENES:
Genes carried on Y chromosome
EX:
Hairy pinna
_________genes only show up in _______
Make a cross with a y-linked gene
Hairy ears is a
________________
________________
trait
Use ______ for hairy ears.
Use ______ for recessive normal ears.
On y chromosome so write it as ________
Make a cross with a y-linked gene
X
X
H
y
X
ALL GIRLS =
____________
ALL BOYS =
____________
Sex chromosomes can
carry other genes
X-LINKED GENES:
Genes carried on
the X chromosome
EX: _____________
_____________
_________________________
Make a cross with an X-linked gene
Hemophilia is an
________________
________________
disease
Use ______ for normal dominant blood
clotting gene.
Use ______ for recessive hemophilia gene.
On X chromosome so write it as ________
Mother
Without hemophilia = X X
Without hemophilia = X X
With hemophilia = X X
Father
Without hemophilia = X y
With hemophilia = X y
Make a cross with an X-linked gene
H
X
H
X
h
X
y
Carrier Mom X
Normal dad
GIRLS
_______ = normal
_______ = look normal
but are
CARRIERS
BOYS
_______ = normal
_______ = hemophilia
Make a cross with an X-linked gene
Colorblindness is an
________________
________________
disease
Use ______ for normal dominant color gene
Use ______ for recessive colorblind gene.
On X chromosome so write it as ________
Mother
normal vision = X X
normal vision = X X
colorblind = X X
Father
normal vision = X y
colorblind = X y
Color blindness is sex linked
Xb
X
B
X
B
y
GIRLS = _______________
BOYS = ________________
HOMOZYGOUS
Normal Mom X
colorblind dad
SEX LINKED TRAITS show
up
in different % in males and
females because they move with
the sex chromosomes
Y linked genes ________ show up in males.
X linked recessive genes appear __________
in males than females.
Females can be __________ for X linked
recessive traits.
Males can _________ carriers for X linked
recessive genes. The either have trait OR are
normal.
SEX INFLUENCED
TRAITS
not carried on sex
Genes ___________
chromosomes BUT affected by
____________
sex hormones of individual with
gene
Male Pattern Baldness
Autosomal
dominant gene
YOUR SEX CHANGES THE
EXPRESSION OF THE GENE
B is dominant for baldness
B’ is recessive for not bald
If you are MALE:
BB =
BB’ =
B’B’ =
If you are FEMALE:
BB=
BB’=
B’B’=
Will they be bald?
Bald = B
BX
B’X
B’X
By
Autosomal
Dominant gene
Bald dad X
pure non bald mom
Will they be bald?
Bald = B
B’X
BX
B’X
B’y
Autosomal
Dominant gene
NOT BALD dad X
NOT BALD mom
(who had a bald dad)
How are genes passed on over
generations?
PEDIGREE
CHART
Males =
Females =
Has trait =
Carrier =