Evolution of multigene families.  It has been proposed that most plant nuclear genes occur in multigene families, which in most cases are the result of gene duplication. Possible outcomes of the duplicate genes include the retention of the original function, and most importantly, the acquisition of a new function.  Therefore, multigene families are important as potential sources of genetic variation; however, only a limited number of multigene families has been studied in angiosperms. Some relevant questions to answer are whether these gene families are undergoing the homogenization process termed “concerted evolution’ and to what extent processes such as gene conversion and nucleotide substitution are occurring.  With these questions in mind, my research has been focusing on the analysis of the nuclear ribosomal genes in Quercus. Contrary to the general belief that plant nuclear ribosomal genes undergone full homogenization, preliminary results from my research indicate that nuclear ribosomal genes in the oak genome occur in the form of subfamilies.  To gain a better understanding on the evolution of multigene families, I plan to sequence and analyze other nuclear genes; potential candidates are the adh, leafy, and calmodulin genes.  Furthermore, I intend to perform cytological studies using fluorescent in situ hybridization (FISH) to map the chromosomal location of these family members.  The results obtained from this study will be compared with available data in other plant taxa and conclusions on the general patterns of evolution will be drawn.