Part III:

You finally graduated top of your class and have taken a position as a cytogeneticist. Your job is to construct the karyotypes of your patients in order to look for possible chromosomal abnormalities. Each karyotype has been started for you. The first 12 chromosomes have been matched. Your job is to match the remaining 11 chromosomes, determine whether or not your patient has a chromosomal abnormality and if so, which one, and to diagnose the patient with the expected symptoms of their karyotype. You better get started, your patient list is growing.....

Case 1:
Case 2:
Case 3:
Case 4:
Case 5:
Case 6:
Case 7:
Case 8:

Now that you have correctly determined each of the above karyotypes, it is essential to understand how they occur. The abnormalities viewed above are mostly cases of trisomies. Trisomy occurs during meiosis when nondisjunction occurs. Nondisjunction is a failure of chromosome or chromatid to separate to opposite poles during nuclear division. When nondisjunction occurs, two chromosomes or chromatid go to one pole and none go to the other.

Click

here

for visualization of this process.