1. recessive

2. What causes PKU? How is it treated?
People (including infants) with PKU need to follow a diet that limits foods with phenylalanine. This includes
infants.
Pregnant woman with PKU need to strictly follow the low-phenylalanine diet throughout pregnancy to ensure the healthy development of infant.
PKU is caused by mutations in the gene that helps make an enzyme to break down phenylalanine in the body.

3. Recessive? Dominant? Codominant?
Sickle-Cell Disease
Recessive? Dominant? Codominant?
Sickle-cell disease affects one out of 400 African-Americans
The disease is caused by the substitution of a single amino acid in the hemoglobin protein in red blood cells
Symptoms include physical weakness, pain, organ damage, and even paralysis
Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

4. Sickle Cell Anemia
Sickle cell disease is more common in certain ethnic groups, including: People of African descent, including African-Americans (among whom 1 in 12 carries a sickle cell gene) Hispanic-Americans from Central and South America. People of Middle Eastern, Asian, Indian, and Mediterranean descent.

6. Distribution of....
Malaria
Sickle Cell Gene

7. polydactyly Frequency of Dominant Alleles
Dominant alleles are not necessarily more common in populations than recessive alleles
For example, one baby out of 400 in the United States is born with extra fingers or toes
                              
Photos: eHand.com
(the electronic textbook for hand surgery)
Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

8. Inheritance of Sex-Linked Genes
The sex chromosomes have genes for many characters unrelated to sex
A gene located on either sex chromosome is called a sex-linked gene
In humans, sex-linked usually refers to a gene on the larger X chromosome
Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

9. Sex-linked genes follow specific patterns of inheritance
For a recessive sex-linked trait to be expressed
A female needs two copies of the allele
A male needs only one copy of the allele
Sex-linked recessive disorders are much more common in males than in females
Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

10. Write down this example in your notes.
Fill in the last box of the Punnett square.

11. Fig b
Sex-linked recessive

12. Color Blindness
some forms are
Sex-linked

13. Hemophilia Sex-linked recessive
pingrybiology.pbwiki.com
Hemophilia is a rare, inherited bleeding disorder in which blood doesn’t clot normally. People with hemophilia may bleed for a longer time than others after an injury. Individuals with the disorder may bleed internally, especially in knees, ankles, and elbows. This bleeding can damage organs or tissues and, sometimes, be fatal.

14. Click here to view Sex-Linked Video
Fig. 15-5
Click here to view Sex-Linked Video X
Figure 15.5 Human sex chromosomes Y

15. Now do problems 13 and 14 in your 2-page genetics problems packet
Now do problems 13 and 14 in your 2-page genetics problems packet. They are sex-linked problems.

16. The Romanovs
Photo:

17. Hemophilia & The Royal Family
The European Royal Family
                                                                                                                                                                       
back
Click here to watch pedigree video

18. Time for Harry Potter Pedigrees

19. Time for Genetic Disorders Crosses
(shade out the boxes of each 4-square
Punnett that are not needed as you
work each problem).