BIOL 1F25 Lecture Notes - Lecture 19: Tumor Suppressor Gene, Brca1, Brca2
27 Nov 2016
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Document Summary
Malignant tumours are invasive, but benign tumours do not have the capacity to cross/ grow past the basal lamina. Steps to show a genetic component to a trait: familial patterns, several families in diverse locations, association (linkage) with well-defined traits, isolation of a dna sequence that looks as though it could be associated with the trait, confirmation! Looked at a hypothetical gene that could be responsible for predisposition to cancer. Mutated form found in individuals with a predisposition to early onset breast cancer. At birth, they have one normal allele, and one defective gene for brca1. Individuals without this predisposition are born with two normal, non-mutant alleles of brca1. ****generally, at least 2 mutations need to take place in order for cancer to occur. Already having one defective gene means that only one more mutation needs to occur, therefore increasing the probability of the individual contracting cancer. Brca2 - also a tumour suppressor gene, involved in repair of damaged dna.
