1. Chromosome Disorders

2. Prenatal Diagnosis

3. Amniocentesis A small sample of the amniotic fluid surrounding the baby is removed using a syringe. The fluid contains skin cells from the baby. The skin cells are grown in the lab.

5. The chromosomes from the cells are magnified under a microscope and a picture is taken. The chromosomes are cut out and arranged in homologous pairs in decreasing size order. This is called a karyotype.

9. Down Syndrome (Trisomy 21) Extra chromosome 21 in every cell of the body Causes mental retardation, heart defects Karyotype = 47,XX+21 or 47,XY+21

11. As a woman gets older, her chances of having a baby with a chromosome abnormality increases ***remember, a woman is born with all of her egg cells, but meiosis is not yet complete (egg development stops in prophase I until the follicle matures prior to ovulation)

12. Most cases of Down syndrome are caused by nondisjunction during meiosis Nondisjunction: homologous chromosomes do not separate properly

13. http://www.mhhe.com/biosci/genbio/biolink/j _explorations/ch10expl.htm

15. Turner Syndrome 45,X Characteristics short stature ovaries do not develop (infertile) cardiovascular problems kidney and thyroid problems skeletal disorders such as scoliosis

17. Klinefelter Syndrome 47,XXY Characteristics Infertility (cannot produce a lot of sperm) Learning disability

18. Trisomy 13 severe birth defects mental retardation

19. Trisomy 18 severe birth defects mental retardation