22 - Microsatellite protocols

Abstract

New techniques are permitting molecular biologists and geneticists to systematically evaluate and compare large areas of the human genome. Much of this analysis is based on the PCR amplification of microsatellites. This chapter explores the microsatellite protocols. Microsatellites have been particularly useful for comparative genetics and genomic mapping as their first description because of several fortuitous characteristics, such as first, microsatellite sequences show a high degree of length polymorphism. Human subjects average >70% heterozygosity at individual microsatellites. Second, microsatellite sequences are abundant and evenly distributed throughout the genome. Microsatellite analysis is becoming instrumental in gene discovery. The detailed allelotyping provided by microsatellites has enabled geneticists to localize familial disease genes by linkage analysis. Microsatellite analysis has been instrumental in the discovery of tumor suppressor genes deleted in malignant tumor cells. Tumor suppressor genes are usually inactivated by deletion of one allele and point mutation of the other allele. Progressive discovery of new microsatellite sequences and their markers has enabled the development of a comprehensive map of the human genome. Over 5000 microsatellites have been utilized in this endeavor as of 1996, and the number of microsatellite markers identified has increased 10-fold duting the past 5 years, permitting finer resolution of the genetic mapping. The chapter discusses the protocols of microsatellites and also provides troubleshooting for modification of these protocols. In addition, the chapter also provides interpretation of microsatellite analysis.