Bean genomic polymorphism uncovered by a systematic approch based one ?-tubuline gene sequence organization

One of the main task in plant breeding is the identification of germplasm containing genes that could improve the performance of currently established cultivars. In the past few years, molecular markers, in association with more powerful statistical models, have been applied to genetic analysis and breeding of several crops. Moreover, advances in molecular biology have allowed the development of rapid, sensitive and specific screening methods to study genetic diversity and relatedness among plant species and varieties. One recently developed, useful genotyping method is based on intron length polymorphisms present in members of the plant ?-tubulin gene family (cTBP). The genomic organization of these genes, that encode proteins of relevance for growth, is such to allow a multiple approach for detection of genetic diversity. The cTBP method for plant genotyping is fast, reproducible, transferable among species, capable of recognizing single components in heterogeneous mixtures and doesn't require preliminary knowledge of the target genome. In addition to the classic cTBP method, we are now introducing a new approach that uncovers gene-sequence variability in the 5'upstream region of the beta-tubulin genes. Applied on different cultivated plants, this AFLP-like technique holds the potential to become a new powerful DNA fingerprinting tool for studying genetic relationships and diversity.