HMB265H1 Lecture Notes - Lecture 2: Inbreeding Depression, Ovarian Cancer, Tumor Suppressor Gene
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HMB265H1 Full Course Notes
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Alleles usually differ at one or several nucleotides out of thousands. Alleles: different versions of the same gene. Mutations: nucleotide sequence of an allele changes as a result of a rare chemical accident. Chromosome segregation at eh molecular level: restriction fragment length polymorphism: Restriction enzymes: bacterial enzymes that cut dna at specific base sequences (by chance) Southern hybridization is used to reveal rflp. Full/complete dominance: expressed when at least one copy is present. Allelic series: multiple alleles with the wild type and a known mutant. Null mutations: produces non-functional proteins: do not produce a functional protein, many genes are haplosufficient so null mutations have no effect on phenotype, happloinsufficiency makes null alleles dominant and affects phenotype. The mutant allele interferes with the wildtype, blocking it. Incomplete dominance: occurrence of intermediate phenotype (black + white = gray) Codominance: expression of both alleles of the heterozygote (black + white = spotted) Recessive lethal alleles: capable of causing the death of an organism.