MITOCHONDRIAL GENOME DIFFERENTIATION IN THE GENUS PHYLLOSTACHYS

Mitochondrial genome differentiation in the genus Phyllostachys was in vestigated by restriction fragment length polymorphism (RFLP) analyses of the restriction fragment patterns or Southern hybridization patter ns of endonuclease-treated mitochondrial (mt) DNA. First, intraspecifi c variation of mtDNA in 3 species, P. pubescens, P. nigra and P. bambu soides, was studied using a large number of samples collected from dif ferent locations in Japan. Little intraspecific differentiation was de tected in P. nigra and P. bambusoides, whereas P. pubescens showed som e intraspecific variation. Second, the restriction fragment patterns a nd Southern hybridization patterns of mtDNAs of 13 Phyllostachys speci es were analyzed. Their comparison indicated that P. nigra and P. dulc is, and P. angusta and P. propinqua have the same mitochondrial genome , respectively. The restriction patterns allowed the identification of 9 out of 13 species. Based on the percentage of common restriction fr agments, all the species except for P. aureosulcata were clustered int o the following 3 groups by the UPGMA method; (1) P. angusta, P. propi nqua, P. pubescens and P. praecox, (2) P. nigra, P. dulcis, P. humilis and P. aurea, and (3) P. bambusoides, P. bissetii, P. viridis and P. makinoi. Clustering of 13 species based on the results of Southern pat tern analysis led to the identification of the following 4 groups; (1) P. angusta, P. propinqua, P. aureosulcata, P. pubescens, P. praecox a nd P. bambusoides, (2) P. nigra and P. dulcis, (3) P. bissetii, P. vir idis and P. makinoi, and (4) P. humilis and P. aurea. The results of t he 2 methods differed in the following aspects; (1) affiliation of P. bambusoides differed, (2) cluster 2 in the restriction pattern analysi s was divided into 2 clusters by Southern pattern analysis, and (3) in tercluster relationships were considerably different between the 2 den drograms. To develop reliable phylogenetic relationships in the genus Phyllostachys, it is necessary to increase the number of restriction e nzymes used in the restriction pattern analysis as well as the number of probes used in the Southern pattern analysis.