Karyotypes & Chromosomal Abnormalities

Critical Thinking Practice Image Analysis – Cell Division Write down five observations about the image below. Name the phase AND type of cell division shown in the diagram. Explain how you know using your observations as evidence.

Karyotyping A Karyotype is a picture of real chromosomes arranged in homologous pairs Scientists or doctors take photos of a cell during division and “unscramble” the chromosomes using computer software

Two Types of Chromosomes Sex Chromosomes Determine the sex of the organism Typical human male: X Y Typical human female: X X 1 pair in humans Autosomes All other chromosomes 22 pairs in humans

Typical Human Karyotypes Male Female

Chromosomal Disorders In nondisjunction chromosomes do not separate properly during meiosis; changes the final number of chromosomes Trisomy – 3 copies of a chromosome (1 extra) Monosomy – 1 copy of a chromosome (1 less)

Chromosomal Disorders

Chromosomal Disorders Male or female? Typical or atypical? What kind of abnormality has occurred? Trisomy 21 (Down Syndrome)

Chromosomal Disorders Structural mutations affect chunks of chromosomes but do not change the total chromosome number Deletion – loss of a chunk of chromosome Duplication – many extra copies of chunk Inversion – direction of chunk reversed Translocation – chunk breaks off and relocates to a NON-homologous chromosome Often difficult or impossible to see on a karyotype!

Chromosomal Disorders Pamphlet Work in pairs to create a pamphlet or poster for a chromosomal disorder. Each pamphlet/poster must have: Name of the disorder A description of the structural mutation or nondisjunction that causes the disorder Symptoms of the disorder At least 5 additional facts about the disorder At least 2 images Sources cited on back Down Syndrome Cri du Chat Turner’s Syndrome Fragile X Klinefelter Syndrome Patau Syndrome Edward’s Syndrome