Genomic colinearity as a tool for plant gene isolation.

Plant genomes show genomic colinearity in spite of the tremendous variability exhibited in their genome size and chromosomal constitution. Comparative genetics can assist in isolation of a mapped gene in a large genome plant species using a small genome plant as a surrogate. Here, we describe various steps involved in the process of gene isolation using genomic colinearity. This involves fine resolution mapping in the large genome species and using common low copy number DNA markers that map to orthologous regions in small and large genome species to isolate candidate genes from the small genome species. Further, alternate strategies are described in cases where the targeted gene is absent in the orthologous region of the small genome species. We also discuss various technologies that can be used for the confirmation of candidate genes.