ALLOZYME VARIABILITY WITHIN AND DIVERGENCE AMONG POPULATIONS OF THE LIVERWORT CONOCEPHALUM-CONICUM (MARCHANTIALES, HEPATICAE) IN JAPAN

Genetic variation within, and divergence among, populations of the liv erwort Conocephalum conicum were estimated from the study of 17 popula tions and 23 putative gene loci. Two additional multilocus genotypes ( ''T'' and ''FS'') were detected in Japan, along with the previously re ported ''J'' type. These three multilocus genotypes differed both morp hologically and ecologically. All eight populations from western Japan included only the J-type and exhibited low genetic variation within p opulations: Nei's (1973) average gene diversity (H) = 0.080 +/- 0.029. In contrast, co-occurrence of several multilocus genotypes in each po pulation from the Kanto District resulted in much higher levels of gen etic variation (H = 0.218 +/- 0.037). If the three genotypes are disti nguished, H values are 0.113 +/- 0.030 for T-type, 0.107 +/- 0.033 for FS-type, and 0.083 +/- 0.018 for J-type. Using C. japonicum, which sh owed low genetic variation (0.014 +/- 0.010) as an outgroup, each geno type formed a monophyletic clade, and the J- and FS-types were more cl osely related to each other than to the T-type. Populations of western Japan and the Kanto District also differed in the degree of gene dive rsity among populations, but the reasons for these differences are obs cure.