1. Notes: Chromosomes and Chromosome Disorders

2. Characteristics
Chromosomes are long, threadlike groups of genes made up of DNA; found in the nucleus.
Chromosomes are always an even number
Examples: Humans – 46
Dogs – 78
Mosquitoes – 6
Goldfish – 94
Each chromosome has many genes on it!

3. Human Chromosomes Each person has 46 chromosomes
(23 from your mom and 23 from your dad)
1. Autosomes – first 22 pairs (44 total)
2. Sex Chromosomes – 23rd pair (2 total)
XX = female
XY = male

4. Amniocentesis
One way to detect genetic defects is to obtain fetal cells through a needle inserted in the amniotic sac of a pregnant woman.

5. Karyotype
A method of organizing the chromosomes of a cell in relation to size.
It is a tool used to help detect genetic defects

6. Mutations
Down’s syndrome – extra #21 chromosome; mental deficiencies, short stature, short wide neck, stocky arms and legs, sterile.
Turner’s syndrome – XO (female’s with only one X) they are shorter than normal.
Klinefleter’s syndrome – XXY (male’s with an extra X chromosome) they are taller than normal.
Cri-du-chat (French for Cry of the Cat). Missing part of chromosome #5. When babies are born with this they sound like a cat crying. Downward slant to the eyes, Low birth weight, mental deficiencies, Skin tags just in front of the ear, small head, small jaw, Wide-set eyes

7. What disorder? Male or female?
Cri-du chat

8. What disorder? Male or female?
Down’s syndrome
Female

9. What disorder Male or female?
Turner’s syndrome
Female
Sisters….one with Turner’s syndrome

10. What disorder? Male or female?
Kleinfelter’s Syndrome
male