1. Learning Targets “I Can…”
-Describe homologous chromosomes and identify the chart used to organize homologous chromosomes.
-Create a karyotype from a given set of chromosomes.
-Identify the sex chromosomes on a karyotype to determine the gender of an individual.
-Diagnose any nondisjunction errors in a given karyotype.

3. Karyotype

4. Sex Determination

8. Assignment for today:
Create a karyotype from the given set of chromosomes
Determine:
1. The gender of your child
2. If there are any missing or extra chromosomes and where
3. The name of the disorder (if there is one)
4. The symptoms of the disorder

9. Down Syndrome
(aka Trisomy 21)
Defects in the number of chromosomes can come from chromosome NONDISJUNCTION during meiosis

10. Normal Meiosis Chromosomes separate from each other during . . .
Anaphase I
Anaphase II

11. Nondisjunction during meiosis

13. NONDISJUNCTION increases with the mother’s age
No one is sure why this happens!
After age 35, amniocentesis is suggested to diagnose extra or missing chromosomes
Nondisjunction errors are RANDOM!

15. Nondisjunction of 21st Chromosome (Most Common)

16. Nondisjunction of Sex Chromosomes

17. Assignment for today:
Create a karyotype from the given set of chromosomes
Determine:
1. The gender of your child
2. If there are any missing or extra chromosomes and where
3. The name of the disorder (if there is one)
4. The symptoms of the disorder

18. References