Transcript B_Pedigree Introduction (1) LW

• Please turn in your Dragon Lab if you
haven’t done so already.
• There will be a test over Genetics and
Pedigrees on Thursday
Page 342
Section 14-1
A circle represents
a female.
A horizontal line connecting
a male and female
represents a marriage.
A half-shaded circle
or square indicates
that a person is a
carrier of the trait.
A completely
shaded circle or
square indicates
that a person
expresses the
trait.
Go to
Section:
A square represents
a male.
A vertical line and a
bracket connect the
parents to their children.
A circle or square
that is not shaded
indicates that a
person neither
expresses the trait
nor is a carrier of
the trait.
• Please make a pedigree for the family
described in the radio story.
This pedigree shows the inheritance of
attached ear lobes, a recessive trait.
• Which parent has attached ear lobes?
I -2
I
1
2
II
1
III
2
3
1
4
2
• How many people are there in the 2nd
generation?
4
I
1
2
II
1
III
2
3
1
4
2
Attached earlobes is a recessive trait. What
is the genotype of people with attached
earlobes?
ff
This pedigree shows the inheritance of
attached ear lobes, a recessive trait.
• What is the genotype of the circled
individuals?
ff
I
1
2
II
1
III
2
3
1
4
2
This pedigree shows the inheritance of
attached ear lobes, a recessive trait.
I
1
2
ff
II
1
2
3
4
ff
III
1
2
ff
• Is it possible for someone with the
genotype FF to have a child with the
genotype ff?
– No, the kid would have to get a F from their
parent.
This pedigree shows the inheritance of attached
ear lobes, a recessive trait.
What is the genotype of the circled individuals?
Ff
I
1
2
ff
II
1
2
3
4
ff
III
1
2
ff
This pedigree shows the inheritance of attached
ear lobes, a recessive trait.
What is the genotype person II-2?
Ff
I
1
2
Ff
ff
II
1
2
3
Ff
Ff
ff
III
4
1
2
ff
This pedigree shows the inheritance of attached
ear lobes, a recessive trait.
What is the genotype person III-1?
F?
I
1
2
Ff
ff
II
1
2
ff
III
3
4
Ff
Ff
Ff
1
2
ff
What evidence do you have the attached earlobes
is a recessive trait?
Person III – 2 has attached earlobes and neither of his
parents do. This could not happen with a dominant
trait.
I
1
2
Ff
ff
II
1
2
ff
III
3
4
Ff
Ff
Ff
1
F?
2
ff
• Add genotypes to your pedigree
• Remember that Huntington’s is a
dominant disease.