Lecture 10 Mapping , I Feb 5 , 1998 Lecturer

Like geographical maps, maps of target DNA molecules give locations of “landmarks,” and orient the user by relating each landmark to all others. Maps of DNA are composed special features, or markers, along the molecule, and are useful in sequencing and in homing in on genes. There are two main classes of mapping techniques: genetic mapping is based on statistical analysis of inheritance patterns, and gives a relative ordering of markers used; and, physical mapping is based on physical and biochemical experiments on DNA sequences. In general, there are many different physical mapping techniques which have varying degrees of resolution; we discuss a few at a very high level. We then introduce the STS mapping problem, and describe the PQ-Tree Algorithm, which solves the problem in the case of perfect data. Outline of Maps: A wide variety of mapping strategies are in use. Major ones, roughly in order of increasing resolution, include: