Roznorodnosc genetyczna z perspektywy poznanych sekwencji genomow roslinnych

Genome analyses in model species have provided value in biological research. As it has become clear that coding gene sequences are well conserved among genera and even tribes, comparative mapping makes it possible to transfer the information on chromosome structure and gene organization from species with well-developed genetic maps to species where such information is scarce. Furthermore, genome comparisons on the basis of a well characterized model genome in relation to more complex genomes in crop plants, offer new information about the mechanisms responsible for the evolution of chromosomal structure. Among dicotyledonous plants, A. thaliana plays the role of a model plant, especially for closely related crop species of the genus Brassica (cruciferous oilseeds and a variety of leafy vegetables). The A. thaliana genome project provides an opportunity of systematic and large-scale identification and isolation of Brassica genes, and to a better understanding various aspects of the Brassica biology and, eventually, of its breeding problems. This aspects is demonstrated on an example of the A. thaliana gene families coding for ACC syntases and oxidases, key enzymes in ethylene biosynthesis. Further progress in the analysis of A. thaliana and rice genomes should establish the synteny with many related crop species by means of detailed comparative mapping. This may greatly facilitate gene identification and studies on their organization within the genome.