Application of the matK gene sequences to grass systematics

The 3' region of the matK gene from 17 species, representing 13 tribes and six subfamilies of the Poaceae, is used to investigate the potential of the gene in addressing systematic questions in the family. The aligned sequences were analyzed by the Wagner parsimony methods using PAUP and PHYLIP and by the neighbor-joining method. Out of the 583 bp sequenced, 30% were variable and 14.9% were informative. The strict consensus tree, rooted by Joinvillea (Joinvilleaceae), showed well-resolved major clades that represent the grass subfamilies. The bambusoid Phyllostachys appeared as a basal clade in the family. Oryza diverged either before or after the Pooideae in the parsimony and neighbor-joining methods, respectively. The three members of the Pooideae grouped in a monophyletic lineage in both analyses. Arundo (Arundinoideae) was basal to the subfamilies Panicoideae and Chloridoideae. Analysis of the various types of DNA mutations underscores the potential of the matK gene in providing insight into grass systematic and evolution.