Predicting progress in physical mapping projects: Effects of inhomogeneity

A complete physical map of the {\sc dna} of an organism consists of ordered overlapping clones spanning the entire genome. Such a map is a useful tool for further genetic analysis, like gene location or sequencing of specific regions in the genome. To plan a physical mapping project, we study the probability distribution of islands with respect to the number of clones and anchors used. The main quantities of interest are the mean number of islands, the mean length of islands and the mean proportion of the genome covered by islands.