BIO 315H Lecture Notes - Lecture 5: Colorectal Cancer, Dna Mismatch Repair, Mutation Rate
Document Summary
Mutations in mismatch repair genes lead to hereditary forms of colorectal cancer. Mutations occur randomly and those with the resistance mutations survive and reproduce. If mutation is a response, you should not see resistance before the treatment. If mutation is random, then you should see resistance before the treatment and more resistance after the treatment. Most colonies were wiped out completely, but some colonies survived and reproduced, indicating that the mutation was already there. On average we have 2-12 x 10^-6 mutations/gene. Average mutation rate in gamete-producing eukaryotes is higher that that of prokaryotes. Because many cell divisions occur between zygotes and meiosis in germ cells, more chance to accumulate mutations. Human sperm have higher mutation rate than human eggs. Each child contains abt 69 mutations (base pairs different from each parent). Mutation rate in sperm is higher because male sperm cells undergo mitosis continually. Transitions purine to purine (g to a)
