BI226 Lecture Notes - Lecture 6: Williams Syndrome, Turner Syndrome, Cri Du Chat
Document Summary
Euploidy and aneuploidy: species-specific characters, number of chromosomes in a nucleus, size and shape of chromosomes, euploid number, number of complete sets of chromosomes, can be n, 2n, 3n, etc. If cells don"t contain the euploid number, then the number of chromosomes in those cells are aneuploid. Leads to changes in chromosome number: failed chromosome and sister chromatid segregation, results in abnormalities in chromosome numbers. Gene dosage alteration: blakeslee and belling, studied aneuploidy of jimson weed, studied how phenotypes were different. Due to changes in gene dosage (the numbers of copies of a gene) Low iq, folds over eyes, short and broad hands, low height. Gynandromorphs: produced by sex-chromosome mosaicism, when individuals have some male and some female cells, due to sex-chromosome non disjunction in early development. Polyploidy: three or more sets of chromosomes in the nucleus of an organism, autopolyploidy, duplication of chromosome sets, methods leading to this: Multiple fertilizations of one egg by multiple pollen grains.
