1. Bellwork: 4/15 Put your phone up  Week 4/15 - 4/19
Gary has Type A blood. Gary’s mom has Type O blood & her husband has blood Type AB. Gary thinks he looks more like his uncle Larry. Larry is homozygous for blood Type A. What are the chances the husband could be the father. What are the chances Larry could be the father?

2. Today:
Bellwork
Part 5 Notes
Sex-Linked Traits Packet

3. Materials
Unit Book
Sex-Linked Traits Pkt

4. This Week: Monday: Pt. 5 Notes & Practice
Tues/Wed: Sex-Link Quick Lab & Movie
Thursday: Quiz, Pt. 6 Notes, & Practice
Friday: Practice & White Board Practice

5. Next Week: Monday: Study Guide (maybe Kahoot) Tues/Wed: Test
Thursday: Presentations
Friday: Presentations

6. Homework Sex-Linked Traits Packet Genetics Project Unit 6 Test
Due next class
Genetics Project
Due 4/24 at 11:59pm
Unit 6 Test
Period 4 & 6: April 23
Period 5 & 7: April 24

7. Unit VI: Mendelian Genetics

8. Part V: Sex-Linked Traits

9. Intro ?s
Genetically, what determines whether a fetus is a boy or a girl?
Who determines gender, Mom or Dad? Explain

10. Human Chromosomes Humans have 23 pairs of chromosomes
1-22 chromosome pairs are…
Autosomal chromosomes (autosomes)
Chromosomes not related to gender
23rd chromosome pair are the sex chromosomes
XX=female
XY=male

11. Human Chromosomes

12. Sex-Linked Disorders Most X-linked genes
Have no homologous loci (positions on Y)
Very few genes found on the Y chromosome
Most genes on the Y chromosome associated with maleness
More than 100 have now been mapped

13. Role of Father in Passing Sex-Linked Traits
Father determines gender
Donates Y chromosome to son
Donates X chromosome to daughter
Fathers cannot pass sex-linked traits to son because…
He does not give him an X chromosome
Males receive X chromosome from mother
So the mother passes sex-linked traits to son

14. Role of Mother
Pass sex-linked alleles (X) to both daughters and sons

15. Sex-Linked Traits More Common in Males…WHY?
Females have fewer sex-linked disorders because…
It only show up if homozygous recessive
Females have two X chromosomes
Males have only one X chromosome
If they have one disorder allele, they have the disorder
More common to have sex-linked disorders

16. Practice Problem
Red-green color blindness is a sex-linked trait. The dominant allele, C, produces normal color vision. The recessive allele, c, produces red-green color blindness.
If a man with normal color vision marries a color-blind woman, what is the chance of them having a color-blind son?
A color blind daughter?

17. Common Sex-Linked Disorders
Color Blindness
Most commonly red-green color blindness
X-linked recessive disorder
Individuals with this color blindness see fewer than 25 colors
Results from some or all of the receptors respond to red and green being weakened or absent

19. Common Sex-Linked Disorders
Hemophilia A
Causes lack of blood clotting
X-linked recessive disorder
Symptoms
Tend to bruise easily
Internal bleeding can cause problems with muscles & joints

20. Common Sex-Linked Disorders
Duchenne Muscular Dystrophy
Disease that results in the progressive weakening of skeletal muscles
X-linked recessive disorder

21. Common Sex- Linked Disorders
Fragile X Syndrome
Attributed to autism and mental retardation
Causes large protruding eyes, ears and an elongated face
X-linked recessive disorder

22. Answer ?s in Note Guide