Notes: Chromosomes and Chromosome Disorders

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!

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

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

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

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

What disorder? Male or female? Cri-du chat

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

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

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