MBG 2040 Chapter Notes - Chapter 6: Patau Syndrome, Secondary Sex Characteristic, Turner Syndrome

• School: University of Guelph
• Department: Molecular Biology and Genetics
• Course: MBG 2040
• Professor: Dennis Baker

Document Summary

Chapter 6 variation in chromosome number and structure. Cytological techniques: geneticists study chromosome number and structure by staining dividing cells with certain dyes and then examining them with a microscope. Aneuploidy: refers to a numerical change in part of the genome pertaining to just a single chromosome. Hypoploid: an organism in which a chromosome or a piece of a chromosome us under-represented. Hyperploid : an organism in which a chromosome or a chromosome segment is overrepresented. Trisomie: when u have an extra chromosome, so 3 identical ones. Trisomy in humans: down syndrome, trisomy of chromosome 21: written as 47, xx, +21, can be caused by chromosome nondisjunction in one of the meiotic cell divisions. The nondisjunction event can occur in either parent, but it seems to be more likely in females. The frequency of nondisjunction increases with maternal age. This is due to factors that adversely affect meiotic chromosome behaviour as a woman ages.