Download Round Watermelon vs. Long Watermelon

Round Watermelon vs. Long Watermelon
Watermelon with round fruit is dominant over watermelon
with long, oval fruit.
Let F = round watermelon
Let f = long, oval watermelon
Cross a purebred round watermelon (FF) with a purebred long
watermelon (ff).
1. What are the percentage odds of getting seeds that produce
round watermelons? __________
2. What are the percentage odds of getting seeds that produce
long watermelons? __________
3. If the seeds from this first cross are grown and the second
generation is allowed to cross, is it possible to get a long
watermelon? ____________
Curly hair vs. Straight Hair
Curly Hair is usually dominant over straight hair in humans.
Let H = curly hair
Let h = straight hair
Cross a mother and father who both have curly hair, but had
one parent with straight hair. (Hint: they are both heterozygous.)
4. What are the percent odds of having a child with curly hair?
_______________
5. What are the percent odds of having a child with straight
hair? ________________
6. Would curly hair or straight hair be the trait that “skips a
generation”? __________________
Long and Short Eyelashes
Long eyelashes are dominant over short eyelashes.
Assign a letter for the dominant and recessive alleles of this
trait.
Cross a mother who is Heterozygous with a father that is
Homozygous recessive for this trait.
7. What are the percent odds that a child will be born with
short eyelashes? __________
Dimples vs. No dimples
Dimpled cheeks are dominant over cheeks without dimples.
Assign a letter for the dominant and recessive alleles of this
trait.
Cross a father who is Heterozygous with a mother that is
Homozygous dominant for this trait.
8. What are the percent odds of getting a child that is
Heterozygous for dimpled cheeks? _________
9. What are the percent odds of getting a child that is
Homozygous dominant? ____________
10. What are the percent odds of getting a child that is
Homozygous recessive? ____________
11. Would a child that is Homozygous recessive have dimples
or not? _____________
Sun Sneezer vs. Non-Sun Sneezer
Although it is estimated to affect only 30% of the population,
the tendency to sneeze when exposed to bright light is a dominant
trait.
Assign a capital letter for Sun Sneezers and the same letter, but
lower case for Non-sun sneezers.
Cross a dad that is a Sun Sneezer from a long line of sun
sneezers (homozygous dominant) with a mom that is a non-sun
sneezer (homozygous recessive).
12. What are the percent odds of having a child that is a sunsneezer? _______________
13. What are the percent odds of having a child that is a nonsneezer? _______________
Sickle Cell Disease
(you can read about sickle cell disease in your textbook on page
B110-B111)
Let R = normal round red blood cells
Let R0 = sickle-shaped red blood cells
Cross two parents that are both heterozygous for sickle cell
disease (RR0).
14. What are the percent odds of getting a child that has sickle
cell disease (R0R0)? ____________
15. What are the percent odds of getting a child that is also a
carrier of sickle cell disease (RR0)? ___________
Blood Type
(you can read about ABO blood type on page B111 of your textbook)
Cross a person with type O blood (ii) with a person that has
type AB blood (IAIB).
16. What are the percent odds of getting a child with each of
the following blood types:
Type O (ii)
___________
Type A (IAIA or IAi) ___________
Type B (IBIB or IBi) ___________
Type AB (IAIB)
___________
17. Using the chart on page B111 of your textbook, can a
person with type AB blood donate to a person with type O
blood? _______
18. What type(s) of blood can a person who is Type O receive?
____________________
Wet Ear Wax vs. Dry Ear Wax
Although it is nearly absent in Asian populations, wet, sticky ear
wax is dominant over dry, flaky ear wax.
Let E = wet ear wax
Let e = dry ear wax
Some American servicemen who fought in Vietnam fathered
children with Vietnamese women during the war. Cross a father
with wet ear wax (assume he is EE) with a woman that had dry ear
wax (ee).
19. What are the percent odds that the baby will have wet ear
wax? ___________
Wet ear wax is associated with a specific type of body odor and, more
seriously, seems to be linked to an increased risk for a specific type of
breast cancer. This type of breast cancer was not known in native
Vietnamese before the war, but has been on the rise in generations
born after the Vietnam War. Scientists are working on a screening test
that looks at the ear wax and body odor of women as an indicator of
their chances of developing this type of cancer.
20. Could a Vietnamese boy with an American father pass on
the allele for wet ear wax (and perhaps breast cancer) to his
daughters? ___________________
Answers to numbered questions:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
100%
0%
Yes (25% of the next generation will be long)
75%
25%
Straight hair
50%
50%
50%
0%
Not
100%
0%
25%
50%
Type O – 0%, Type A – 50%, Type B – 50%, Type AB – 0%
No
Only Type O
100%
Yes (The boy would probably be a carrier, so his daughters may have a 50% chance of getting
the wet ear wax gene from him.)