Linking phylogeny and genetics zea mays as a tool for phylogenetic studies

Model organisms provide opportunities to explore the linkages between genetics and phylogenetics. Zea mays ssp. mays is an ideal system for making these links, in part because it is well known genetically and also because it is within the grass family (Gramineae or Poaceae), which is well known phylogenetically. The phylogeny of the genus Zea is reviewed, and cladograms are presented that locate the genus within the tribe Andropogoneae. Study of the genus and its relatives has been biased toward New World taxa, and thus knowledge of many character systems is incomplete. A number of genes and gene systems have been studied in a comparative context, and all of these could be examined more carefully with an appropriate sample of taxa. Cytogenetics has been extensively explored in some groups, but others are largely unknown. Maps of restriction fragment length polymorphisms are yielding information on the arrangement of the nuclear genome and indicating that significant linkage groups are shared between maize and some of its more distant relatives. The alcohol dehydrogenase genes could provide insights into phenomena of gene duplication and intron loss. The anthocyanin pathway and the C photosynthetic pathway are both well understood at the gene level and could provide the basis for comparative studies of patterns of gene expression. Molecular work on developmental mutants is still in its infancy, but these genes might provide the most direct connection with known cladistic characters. Geneticists and phylogeneticists appear to be moving toward common ground. [Zea; maize; genetics; phylogeny; grasses C photosynthesis, ADH].