Unit 6: Karyotyping Notes Thursday 2-25-2010 Unit 6: Karyotyping Notes

(1) Karyotyping Look at chromosome pairs to identify chromosomal-disorders. Process: Stain nitrogenous bases. Organize homologues from longest  shortest. Organize by banding pattern. Sex chromosomes at the end. Look for too many, missing, shortened, or lengthened chromosomes.

(2) Chromosomes Sex Chromosomes: Normal Numbers: Male = X and Y Female = X and X Normal Numbers: 23 pairs OR 46 total

(3) Down Syndrome Chromosomes: Physical Characteristics: 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

(4) Patau Syndrome Chromosomes: Physical Characteristics: 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

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

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

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