BIOC15H3 Lecture Notes - Lecture 7: Purine, Dosage Compensation, Bacteriophage
9 Mar 2021
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Terminologies: aneuploid mutations variation by a fraction of a set, ex. A single chromosome: euploid mutations variation by a whole set, ex. Chromosome numbers: x = the number of different chromosomes that make up a single, complete set, 1x means one complete set of chromosomes, ex. In humans, 1x = 23 meaning one set of chromosomes of 23 different chromosomes: ex. Autosomal aneuploidy: most autosomal aneuploidies and trisomies are lethal and result in spontaneous abortion, trisomy 21 (down syndrome) is the most frequently observed autosomal trisomy, majority of down syndrome results from nondisjunction during maternal meiosis. Individuals with monosomy 21 survive for only a short time after birth: two autosomal trisomies allow birth, but cause severe developmental abnormalities and early death, trisomy 18 causes edwards syndrome, trisomy 13 causes patau syndrome b. Figure 9. 32 (inactivation doesn"t affect the par region for both x and y)
