1. BIOLOGY
Unit 4.5 Notes:
Karyotyping
& Genetic
Disorders

2. (1) Karyotyping:
•
Purpose:
To look at chromosome pairs to identify
chromosomal-disorders.
•
Process:
1.
2.
3.
4.
5.
Stain DNA.
Organize longest  shortest.
Organize by banding pattern.
Sex chromosomes at the end.
Look for too many, missing, shortened, or
lengthened chromosomes.

3. (2) Chromosomes:
•
Sex Chromosomes:
– Male = X and Y
– Female = X and X
•
“Normal” Numbers:
– 23 pairs OR 46 total

6. (3) Down Syndrome:
•
Chromosomes:
– Trisomy 21 = 3 chromosomes at #21
– Total = 47 chromosomes
•
Physical Characteristics:
– Round-Asian-Like Facial features, short
stature, heart defects
– Shorter lifespan
– Prone to Alzheimer’s and leukemia

7. (4) Patau Syndrome:
•
Chromosomes:
– Trisomy 13 = 3 chromosomes at #13
– Total = 47 chromosomes
•
Physical Characteristics:
– Eye, Brain and Circulatory defects
– Cleft Palate
– Death typical w/in months of birth

8. (5) Edward’s Syndrome:
•
Chromosomes:
– Trisomy 18 = 3 chromosomes at #18
– Total = 47 chromosomes
•
Physical Characteristics:
– Every organ defected
– Death w/in months after birth

9. (6) Klinefelter Syndrome:
•
Chromosomes:
– XXY
– Total = 47 chromosomes
•
Physical Characteristics:
– Male sex organs, but underdeveloped + sterile
– Other feminine body characteristics
– Normal intelligence

10. (7) Turner’s Syndrome:
•
Chromosomes:
– Only 1 X chromosome
– Total = 45 chromosomes
•
Physical Characteristics:
–
–
–
–
–
Female
Do not mature sexually + are sterile
Short stature
Normal Intelligence
(Most die before birth)