GENE20001 Lecture Notes - Lecture 16: Base Pair, Cistron, Wild Type
Document Summary
* recombination frequency is a measure of distance. * if two genes are close then rf is lower. * clearly being able to assay for very low numbers of recombinants means that finer maps can be constructed. Functionally three factor phage crosses are set up to determine which gene (or mutation) is in the middle. Three genes a, b and c with a+/a-, b+/b- and c+/c- alleles, respectively. * genetic fine structure mapping can map mutations between and within a gene. To be able to map points effectively within a gene we need to be able to score large numbers of progeny for recombination. Phage allow us to do this, and even better we can set up the crosses so that only the recombinants can survive and hence be counted among large numbers of progeny. It is possible to plate 108 phage with bacteria on a petri dish.
