Chapter 29 : Mapping a Disease Gene

Abstract:

This chapter explores how DNA markers can be used to map the locations of genes. Maps showing the positions of genes or other inheritable chromosome features, such as short tandem repeats (STRs), as deduced from genetic experiments, are called genetic maps. Genetic mapping is still used, but now it can be combined with physical analyses of DNA to yield much more detailed and accurate information about genes. Genetic mapping was invented long before researchers had the ability to analyze DNA (and before they knew that genes were made of DNA). It is based on the observation of inheritance patterns. Genetic mapping hinges on the measurement of recombination frequency. One recombination event between the nail-patella syndrome (NPS) and ABO loci in 10 paternal haplotypes was observed. The chapter summarizes the frequencies with which alleles of each pair of loci are inherited together. While some scientists were developing better sequencing methods, others focused on the goal of developing detailed maps. To achieve this goal, they needed better mapping techniques and better methods for cloning large amounts of DNA that could be assembled into overlapping fragments. A new discipline within molecular biology, proteomics, focuses on the structures and interactions of proteins.