1. Pedigrees and Sex Linked Traits
Outcome
I will explore how traits are inherited through generations by solving autosomal and sex-linked pedigrees.

3. Sex Chromosomes X and Y are sex chromosomes
The other 22 pairs are autosomal(body) chromosomes
Males = XY
Females = XX
Not true homologous pairs
X has more genes

4. X and Y Males Females Get Y from dad Get X from mom Get one X from dad
Get one X from mom

5. Sex-linked traits X-linked
The inheritance pattern of genes located on the X chromosome

6. Hemophilia Video

7. X-Linked Punnett Square
Sex linked
H=normal & h=hemophilia
Cross: XHXh x XhY
What is the chance that their son will have hemophilia?
What is the chance that their daughter will have hemophilia? XH Xh
XH Xh
Xh Xh Y
XH Y
Xh Y
50%
50%

8. Sex-linked worksheet
Working with your table, complete the sex linked worksheet in your notes.
You will have 6 minutes!

9. Pedigrees
a chart that shows how a trait (phenotype) is inherited through a family

10. Pedigrees circles: females squares: males
shaded: individual with trait/disease
Half-shaded: carriers for a trait but does not express the trait.

11. Generation / Individual Practice
Generations are the rows in a pedigree
Individuals are labeled across a pedigree
Lines down represent offspring I II
III

12. What do we call this individual? Carrier
Quick Quiz
Individual A is
A male who expresses the trait
A female who does not express the trait
A male who does not express the trait
A female who does express the trait
What do we call this individual?
Carrier

13. Quick Quiz Individual D is A male who expresses the trait
A female who does not express the trait
A male who does not express the trait
A female who does express the trait

14. Quick Quiz Individual H is A male who expresses the trait
A female who does not express the trait
A male who does not express the trait
A female who does express the trait

15. Outcome
I will explore how traits are inherited through generations by solving autosomal and sex-linked pedigrees.

16. Fugates of Kentucky: Skin Bluer than Lake Louise

17. Fugates of Kentucky: Skin Bluer than Lake Louise
Methemoglobinemia
blood disorder with an abnormal amount of methemoglobin - a form of hemoglobin
reduced ability to release oxygen to tissues - gives blood a bluish color

18. Autosomal Recessive
Trait appears only when two parents by chance carry the hidden allele
Affected individual inherits both recessive alleles
Example: sickle cell disease
Who could be a carrier?
Color in the carriers

19. Autosomal Dominant
Trait appears in every generation, in about half of descendants (assuming a heterozygous carrier)
Affected individual has at least one dominant allele
Example: Huntington’s disease

20. X-linked Recessive
Mother passes on to half of sons; half of daughters carry it.  Father never passes on trait.
Examples: Hemophilia, color blindness
Why do more men have it?
Who could be a carrier? Can men be carrier?

21. X-linked Dominant
Father passes trait to all daughters; no sons.  Mother passes on to half of children.
Example: Rett syndrome

22. Outcome
I will explore how traits are inherited through generations by solving autosomal and sex-linked pedigrees.