What is Biology Good For ? (#11)
Studying Inheritance of Human Disorders: Genetics Problems!

Note 1: Good For #11 (Genetics Problems) was posted EARLY - Thursday evening 4/1/04.
CLICK ON THE LINK if you still need to complete Good For #10 on Herceptin, due FRIDAY 4/2/04

Note 2:Unlike most Good For assignments, you will NOT submit the answers to this Good For on the web. Instead, print this out, and work the genetics problems below in class and as homework. This Good For is worth 6 extra credit points and is due on MONDAY APRIL 12, 2003 (exam day) in class. You may work with a partner, but you must each turn in a separate paper.

Name:__________________________

Genetics Problems: Please show work - use additional pages if needed. You may work with a friend, or in a group - you may get help from me or other members of the class - BUT - don't take the EZ way out - there will be problems just like this on the Exam. ((I promise! ))

Tip: Remember that for any gene, (doesn't matter what the 'letter' / gene is)
Homozygous dominant = "AA"
Heterozygous (‘carrier’) = "Aa"
Homozygous recessive = "aa"

This is the inheritance pattern for an Autosomal Recessive disorder	This is the inheritance pattern for an Autosomal Dominant disorder

Problems:

1. Freckles (F) is a dominant trait in humans.

a) By convention, the recessive allele for this gene is labeled __________
b) If a person is heterozygous for freckles, what is their genotype? ________
c) If a person is homozygous dominant for freckles, what is their genotype? ________
d) What is their phenotype? _____________

2. A couple has just found out that they are both carriers for PKU, a recessive metabolic disorder. What are the chances that their child will:

a) be phenotypically normal (KK or Kk)? ________
b) be genotypically normal (homozygous dominant)? ________
c) be a carrier for PKU (Kk)? ________
d) have PKU (kk) ________

3. John cannot curl his tongue but both his parents can curl their tongues. Tongue-curling (T) is a dominant trait. Give the genotypes of all persons involved.

John: _____________ Mom:______________ Dad: _______________

4. A woman is a carrier (heterozygous) for Tay-Sachs. What are the chances of her giving birth to a child with Tay-Sachs (a homozygous recessive disorder) if the father is normal (homozygous dominant?) What are the chances of giving birth to a carrier like herself?

5. Both you and your sister have attached earlobes (u) , yet your parents have unattached ones. Unattached earlobes (U) are dominant over attached. Give the genotypes of you, your sister, and your parents.

6. Parents who are carriers for have sickle-cell disease produce a child who has sickle-cell disease. What are the chances that their next child will have sickle-cell disease?

7. A woman with PKU (kk) marries a man who is genotypically normal (KK). What are their chances of having a child who is

a) genotypically normal (KK), ________________

b) a carrier for PKU (Kk), ___________________

c) or have the disease PKU (kk) ?______________

8. If both your parents have a continuous hairline (cc), what are your possibilities for hairlines? (show why this is)

9. Can a couple with achondroplasia (dwarfism), an autosomal dominant disorder, have a child without achindroplasia (aa) - of 'normal' height and stature? What happens to a conception that results in a zygote with the genotype AA?

10. A woman is heterozygous for polydactyly and has 6 fingers on each hand (polydactyly is a dominant trait). What are the chances of her giving birth to a child with polydactyly if the father is normal (homozygous recessive)?

11. If a woman has Blood type AB, what are her possibilities for genotype (alleles)?

______________________________

If a man is Blood type O, what are his possibilities for genotype(alleles) ?

_______________________________

Are these Blood types of kids possible if this woman and man have a baby together ? Yes or NO - AND list genotypes!!!!

A type AB baby? _________________

A type A baby? __________________

A type B baby? ___________________

A type O baby? ___________________

12. Joan (type A blood) and David (type B blood) have two children. All four members of this family have different blood types. List the blood types of the children and the genotypes of all 4 family members:

	Phenotype (Blood type)	Genotype (alleles)
Joan	(type A)	______________
David	(type B)	______________
Joni	(type _____________)	______________
Davy	(type _____________)	______________

Woah! You are now a Genetics PRO!
Reminder: Yes, There will be problems like this on the test! There is no SUBMIT button because this Good For is due IN CLASS