AS.020.331 Lecture Notes - Lecture 24: Point Mutation, Chromosome, Zygote
Document Summary
X-rays were thought to be linked to cancer (leukemia), but this connection was ignored. Also used to image fetuses using contrast. Mueller: biology is saying that x-rays are mutagenic, the medical community is blatantly ignoring it. Today, cancer is a genetic disease that sometimes involves familial mutations that predispose individuals to certain cancers. Steps: begin with the zygote, after many cell divisions, 10^13 cells of identical genotype are formed, mosaic: cells of different genotype arise from the same cell. Often expected when a non-carrier has a second affected child. Mutation is in the germ cell but not somatic cells. Small clones of mutant cells are often unimportant. Often, the mutants grow poorly or die. Large clones of mutant cells can cause a disease phenotype. There is no way that six independent mutations in key genes would happen in a single cell.
