Comparative genomics approaches to the study of drought tolerance

Genomics represents an entirely new conceptual approach to the study and application of biology. Structural genomics uses the rapid generation of huge quantities of precise DNA sequence data to identify genes, and the structures of genes and other elements in a genome. The functions of these genes can be assessed by a number of high-throughput approaches I so-called 'functional genomics'. These techniques include the mapping of complex traits in very large populations, the characterization of correlated expression patterns of every gene within a species under all possible circumstances, and the use of reverse genetics and high throughput mutant screening to identify the phenotypes of mutations in all of the genes within a species. The ultimate goal of genomics is to find every gene and to determine the roles of each of these genes. Comparative genomics takes this goal several steps further: to identify and find the role of every gene in every species, to see what changes are significant in making one species different (in phenotype, growth habit, adapted environment) from another, and to determine how these changes came about. Drought tolerance is a highly appropriate target for comparative plant genomics because only such an information-rich approach is likely to unveil the key genetic contributors to the complex physiological processes involved. The applied goal of comparative plant genomics might be described as identifying all of the genetic variation in the biosphere, whether in crops or in wild species, that can be used to design the most productive, benign and sustainable agricultural systems. One use of this technology could be to find and appropriately utilize the best drought tolerance alleles in nature, regardless of source, for crop improvement. The technology and biological materials needed to accomplish this ambitious goal now exist. All that is lacking are the appropriate team and resources to undertake this important task.