12-4 Changes in Chromosome Number
Karyotype -A picture of a person's chromosomes, arranged by size and grouped into homologous pairs. The last pair (#23) are the sex chromosomes.
Normal Male Karyotype
Tests to Examine Chromosomes
Amniocentesis - a needle is used to withdraw fluid from the uterus which contains fetal cells
Chorionic Villi Sampling - a suction tube inserted into the vagina removes fetal cells
Chromosome Mutations
Occassionally, errors occur during cell division that result in the offspringing receiving too many or too few chromosomes(euploidy)
Polyploidy - three or more complete sets of chromosomes. common in plants
Aneuploidy - when an organism has more or less than the normal
monosomy - missing one chromsosome of a set, Ex. XO
trisomy - has an additional chromosome of a set, Ex. Trisomy #21 causes Down Syndrome
Down's Syndrome ( Trisomy #21)
Other Syndromes -
Turner (XO)
Klinefelter (XXY)
Edward Syndrome (Trisomy 18)
Patau Syndome (Trisomy 13)
Supermale (XYY)
Poly-X Females (XXX)
Student Resources
Karyotype Activity at Learn.Genetics
Karyotype Activity Using Google Slides
12.4 - Changes in Chromosome Structure
Chromosome Mutations
Inversion (B) | Deletion (A) | Duplication (D) | Translocation (C)
Williams Sydrome - deletion on chromosome 7
Cri du Chat Syndrome - deletion on chromosome 5
