PLANT COMPARATIVE GENETICS AFTER 10 YEARS

The past 10 years have seen the discovery of unexpected Levels of cons ervation of gene content and gene orders over millions of years of evo lution within grasses, crucifers, Legumes, some trees, and Solanaceae crops, Within the grasses, which include the three 500-million-ton-plu s-per-year crops (wheat, maize, and rice), and the crucifers, which in clude all the Brassica crops, colinearity Looks good enough to do most map-based cloning only in the small genome model species, rice and Ar abidopsis. Elsewhere, knowledge gained in a few major crops is being p ooled and applied across the board. The extrapolation of information f rom the well-studied species to orphan crops, which include many tropi cal species, is providing a solid base for their improvement. Genome r earrangements are giving new insights into evolution. In fact, compara tive genetics is the key that will unlock the secrets of crop plants w ith genomes Larger than that of humans.