XVI International Botanical Congess

Knotted-like homeobox (knox) genes comprise a gene family in plants. Class I knox genes are expressed in shoot apical meristems, and not in lateral organ primordia. Class II genes have more diverse expression patterns. Gene duplication has contributed to the evolution of families of homeodomain proteins in metazoans. We believe that similar mechanisms have contributed to the diversity of knox gene function in plants. A phylogenetic analysis based on nucleotide sequences shows that class I and II form two distinct clades in the knox gene family. We have mapped meristem expression patterns onto a knox gene tree using kn1/STM-like or KNAT1/rs1-like patterns of gene expression as character states for class I representatives from maize and arabidopsis.