Mapping Functions

Abstract

The raw data for chromosome mapping are the crossover values obtained for loci spaced serially along the physical chromosomes. The simplest map is that of the cumulative sum of crossover values for adjacent genes. This is the map expressed in crossover units. When the loci are sited close together, the cumulative sum gives an accurate representation of the chromosome in centimorgans. Unfortunately, when the loci are not sited close together, the simple one-to-one relationship breaks down. The greater distance, the poorer the representation. To bridge the gulf, it is necessary to derive a mapping function to relate the determined crossover value to chromosome segment length.