HMB265H1 Lecture Notes - Lecture 18: Dna Ligase, Heterochromatin, Euchromatin
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HMB265H1 Full Course Notes
Verified Note
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Lecture 18: changes in chromosome structure (part ii) Del: symbol designating chromo that has sustained a deletion (df= deficiency in drosophila) Homo and hemizyotes tend to not survive deletions. Heterozygotes- w/o one wild type allele- gene dosage is too low and not enough protein is synthesized. Deletion on genetic map: formation of deletion loop. An unpaired bulge of the normal chromosome that corresponds to the region deleted from the other homolog. Gene dosage: number of times a given gene is present in the cell nucleus. If the required amount of gd isn"t attained, could lead to gene imbalance- altering amount of protein created/ not enough: too much. Pseudodominance: deletion in one homolog may unmask the recessive alleles in the normal homolog- demonstrating lack of complementation because neither chromo can produce wild type gene function. Polytene chromosome: found in drosophila- giant chromo consisting of several identical chromatids lying parallel from each other.
