1. Complete the pedigree tracing red hair in this family
Complete the pedigree tracing red hair in this family. The trait in question is always shaded in.
Can you tell if Red hair is recessive or dominant?
Determine the genotypes of each person. If you don’t know 2nd allele leave a _
If a person is “carrier” or heterozygous for the trait shade them half way in.

2. The following pedigree traces Huntington’s in this family.
Huntington’s is dominant disease that causes progressive muscle loss.
Those shaded in have the dominant trait, therefore in completing this there will be
no carriers (no half shaded in)

3. Common Sex-linked disorders/traits 1. Red-Green Colorblindness 2
Common Sex-linked disorders/traits 1. Red-Green Colorblindness 2. Hemophilia 3. Duchenne’s Muscular Dystrophy 4. Male-inherited baldness

4. Red – Green Colorblindness

5. Karyotypes
Female
Male

6. Contains files for making men “men”
Females
Males
Contains files for making men “men”
X Chromosome X Chromosome
X Chromosome Y Chromosome

7. Human Chromosomes
Sex Chromosomes – Carry genes that determine the gender of an individual
Males - XY (Y determines sex – male genes); typically
Females – XX; typically
Often referred to as the 23rd chromosomes

8. Sex Determination – Punnett Square

9. Classic Sex-linked inheritance problem.
A man has normal vision (not colorblind)
How do we write his genotype?
His spouse is a carrier for colorblindness
How do we write her genotype?

10. Figure 14-13 Colorblindness
Section 14-2
Father
(normal vision)
Normal vision
Colorblind
Male
Female
Daughter
(normal vision)
Son
(normal vision)
Mother (carrier)
Daughter
(carrier)
Son
(colorblind)
Go to Section:

12. Genotype of Mom ___________ x ______________ Genotype of Dad

13. Figure 14-13 Colorblindness
Section 14-2
Father
(normal vision)
Normal vision
Colorblind
Male
Female
Daughter
(normal vision)
Son
(normal vision)
Mother (carrier)
Daughter
(carrier)
Son
(colorblind)
Go to Section:

14. Figure 14-3 A Pedigree Section 14-1 Go to Section:
A circle represents a female.
A square represents a male.
A horizontal line connecting a male and female represents a marriage.
A vertical line and a bracket connect the parents to their children.
A half-shaded circle or square indicates that a person is a carrier of the trait.
A circle or square that is not shaded indicates that a person neither expresses the trait nor is a carrier of the trait.
A completely shaded circle or square indicates that a person expresses the trait.
Go to Section:

15. I. Rr Rr
II. R_ R_ Rr Rr rr R_
III. R_ R_ R_ rr R_ Rr Rr

16. Using Pedigree to determine inheritance patterns
Autosomal – Trait is found on chromosome other
than sex chromosome (1-22). Just as likely for male
or female to be affected. May be dominant or recessive. Passed from
carrier mothers to sons.
Examples:
Hair color, eye color, cystic fibrosis, Huntington’s, Limb girdle
muscular dystrophy
Sex-Linked – Found on the X chromosome. Males more
likely to have it because only they only have one X.
Examples: Duchene’s Muscular Dystrophy, colorblindness
hemophilia

17. Color blindness is sex linked recessive trait_ b
X X
X Y
II. B B b B b _ B B B
X Y
X X
X X
X Y
X Y
X X
III. B _ _ B b _ B b B B
X X
X X
X Y
X Y
X Y
X X
X Y