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Section 1 - Genetic Survey p. 112

Table 4 - Your Genetic Characteristics

Trait	Your Phenotype	Dominant/Recessive
1. Ear lobe	Free	Dominant
2. Use of hand	Right	Dominant
3. Tongue rolling	Roller	Dominant
4. PTC tasting	Nontaster	Recessive
5. Chin cleft	No cleft	Recessive
6. Freckles	No freckles	Recessive
7. Color vision	Normal	Dominant (sex-linked)

Section 2 - Blood Typing Demonstration p. 113

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Section 3 - Questions

1.  
   1. If tasting is due to a dominant allele, could two parents who are nontasters have a child who is a taster? Explain.
      No - nontaster is recessive, parents must be homozygous recessive.

   2. Could a parent who is a taster and one who is a nontaster have children who are tasters?
      Yes - the child can be heterozygous.

      Could they have nontasters?
      Yes - the taster parent must be heterozygous and child homozygous recessive.

   3. Could two parents who are tasters have a child who is a nontaster? Explain.
      Yes - if both parents are heterozygotes, 25% of their children can be nontaster.

2. What are the phenotypes of the blood typed in the demonstration? p. 114
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3.  
   1. Which parent gives the X chromosome to a male child?
      Mother; father gives Y chromosome to the boy.

   2. Which parent(s) gives the colorblindness allele to a male child?
      Mother gives colorblind allele to male child.

   3. Which parent(s) gives the colorblindness allele to a female child?
      Both parents must give colorblind allele to female child.

   4. Can a recessive allele be masked for a sex linked trait in a male?
      No, male has only 1 X chromosome.

   5. Is colorblindness more common in males or females? Explain why.
      Males, since they have only 1 X chromosome.

Data tables: a combined parents/child example.

Questions p. 118

Skip #1 - #7 summaries of your family.

General Questions p. 119

8. In regard to hemophilia, colorblindness, and muscular dystrophy, would you expect more affected males or females? Explain why.
   More males should be affected because these are sex-linked traits, and males have only 1 X chromosome.

9. Could a dad with curly hair and a mom with straight hair have a child like either parent? Explain why or why not.
   No - both parents homozygous, child must be SC genotype and have wavy hair.

10. Could a roller and a nonroller have children who are nonrollers?
    Yes: if roller parent is heterozygous.

    Could they have children who are rollers?
    Yes: regardless of whether roller parent is heterozygous or homozygous dominant, because roller is dominant.

11. What are the chances of two normal tone hearing parents producing a tone deaf child?
    0% - normal tone hearing is recessive.

    What are the chances for one normal tone hearing parent and a tone deaf parent to produce a tone deaf child?
    Depends on genotype of tone deaf parent:
    If tone deaf parent is heterozygous - 50%.
    If tone deaf parent is homozygous dominant - 100%.

12. Choose one of the following traits to do a chi-square test...
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