1. Karyotype a picture of an organism’s chromosomes
helps scientists quickly identify
Gender
Chromosomal abnormalities

2. Gender
XY =
male
XX =
female

3. Chromsomal abnormality
Occasionally during the formation of gametes, chromosomal material is lost or rearranged.
1. Nondisjunction – Sperm or egg have too many or too few chromosomes
2. Translocation - Missing or mixed up pieces of chromosomes

4. Amniosentesis
involves sampling the liquid surrounding a fetus to obtain a karyotype before a baby is born

5. ________________ Abnormalities
CHROMOSOMAL
1 in 200 newborns has a chromosomal abnormality
28% of first trimester miscarriages have a chromosomal abnormality
Abnormalities in larger chromosomes don’t usually survive

7. Down syndrome (= ____________)
TRISOMY 21

9. Down syndrome (Trisomy 21)
1 in 800 births
Similar facial features
Slanted eyes
Protruding tongue

10. Down syndrome (Trisomy 21)
Simian line on palm

11. Down syndrome (Trisomy 21)
Most common chromosomal abnormality
50% have heart defects that need surgery to repair
Mild to severe mental retardation
Increases susceptibility to many diseases
Risk of having a child with Down syndrome increases with age of mom

12. Turner syndrome

13. Turner syndrome ____ XO 1 in 5000 births
Females have only one X chromosome
Small size
Slightly decreased intelligence
35% have heart abnormalities
Hearing loss common
Broad chest
Reproductive organs don’t develop at puberty
Can’t have children

14. Klinefelter syndrome XXy

15. Klinefelter syndrome 1 in 1000 births Males have extra X chromosomes
(Can be XXy, XXXy, or XXXXy)
Average to slight decrease in intelligence
Small testes/can’t have children
Usually not discovered until puberty when don’t mature like peers

16. Trisomy 13 (Patau Syndrome)
Serious eye, brain and circulatory defects
Cleft palate
1 in 5000 births
Life span: a few months

17. Trisomy 18 (Edward syndrome)
Effects almost every organ system
1 in 10,000 births
Life span: a few months

18. XYY
Taller than average
Male
Below normal intelligence

19. Trisomy X (XXX) 1 in 1000 Healthy fertile female
You cant tell except for karyotype