1. Reminders Unit 8 Exam- Tuesday, March, 21st
Last day to turn in ANY Unit 7 Work- Tuesday, March, 21st
Assignments completed for Unit 8:
Word Wall
Human Traits
Incomplete Dominance Practice
Reminders

2. Unit 8: Mendelian Genetics 8.4 Other Patterns of Inheritance

3. Phenotype produced when both alleles are clearly expressed.
Traits appear together
Examples:
Red and white spotted cattle (roan)
AB Blood types (the A and B proteins appear on the surface of your blood cells together)
Codominance

4. Using a Punnett Square for Codominance
Use only capital letters- since there is no dominant trait
Place the two traits onto the Punnett square, the same as you have before
Cross the traits in the square
Using a Punnett Square for Codominance

5. Example with Codominance
Jessica has B blood type. Jessica’s mom has blood type O. Jessica has a baby with John, who has type AB blood.
a. parent genotype
b. offspring genotype
c. offspring phenotype
Example with Codominance

7. Sex-Linked The gene is carried on a sex chromosome (x or y)
Occur most often in males because they don’t have another x
Most of these genes are recessive, which means mom can be a carrier and pass the trait to her offspring
Examples:
Hemophilia
Red-green color blindness
Sex-Linked

8. Using a Punnett Square for Sex-Linked
Determine the genotypes of the parents
Mom is a carrier: Xx heterozygous
Mom is NOT a carrier: XX homozygous
Mom shows trait: xx homozygous recessive
Dad “normal”: XY
Dad with trait: xY
Place the traits onto the Punnett square as you have before
Cross the traits in the square
Determine the genotype and phenotype of the offspring
Male = XY, xY
Female = XX, Xx
Using a Punnett Square for Sex-Linked

9. Example with Sex-Linked
Carol is a “carrier” for a recessive sex-linked trait that causes red- green color blindness. Carol has a baby with Bill, who is normal.
a. parent genotype
b. offspring genotype
c. offspring phenotype
d. proportion of male offspring
e. Proportion of offspring with red-green color blindness.

10. Parents:
The McBride’s: type O and AB (1 Punnett)
The Gonzales’: type A and B (4 Punnetts)
The Pepronis: type A and O (2 Punnetts)
Children:
Baby A is type AB
Baby B is type O
Baby C is type B
1. Who are the parents of baby A? A: Gonzales 2. Who are the parents of baby B? A: Pepronis 3. Who are the parents of baby C? A: McBride
Practice In a hospital, 3 babies were born simultaneously during a thunderstorm. The lights went off and the babies were mixed up. The hospital wants to match the baby with its parents by looking at the blood types. Can you help?