Biology 1202B Lecture Notes - Lecture 19: Meiosis, Ivacaftor, Aneuploidy
11 Apr 2016
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Aneuploidy: numerical abnormality (too many or too few chromosomes) X and y aneuploidy is more common as they are less severe. Quanitaive alteraion of gene expression and may do the same, but oten leads to an increase/decrease in copy and expression altering phenotype. 3 autosomal trisomy that survive postnatal, 21(least severe, smallest chromosome), 18 and 13. (less genes=less phenotypic efect) Trisomy 21 due to maternal age; older the egg (woman), greater chance of nondisjuncion due to extended period of ime suspended in meiosis. Phenotypic consequences depend on locaion of breakage point relaive to the genes; potenially no efect, potenial overexpression. Chromosome with an inversion: form a loop, 2 inviable gametes (deleion, duplicaion), and 2 viable and balanced games (one with an inversion) o. Autosomal dominant inheritance o o o o o. Individuals that are homozygous/heterozygous mutant alleles will have the disease. Individuals with 2 defecive alleles will have the disease, 1 defecive allele are carriers and are oten symptom free.
