Gene mapping is the process of establishing the locations of genes on the chromosomes. Early gene maps used linkage analysis. The closer two genes are to each other on the chromosome, the more likely it is that they will be inherited together. By following inheritance patterns, the relative positions of genes can be determined. More recently, scientists have used recombinant DNA (rDNA) techniques to establish the actual physical locations of genes on the chromosomes.
One type of physical map of DNA represents the locations of genes along the chromosome. There are various methods that have been used over the years to deduce gene maps of genomes. Nowadays, the most accurate and efficient approach for building gene maps involves sequencing a genome--or part of a genome--and then using various computer programs to analyze the sequence and identify genes within the sequence. Such a sequence-based approach gives a very precise map of each gene and its subcomponents.- Eric D. Green, M.D., Ph.D.