The extent and structure of genetic variation in the Macrozamia pauli-guilielmi complex (Zamiaceae)

Allozyme variation in 12 enzyme systems coded by 17 loci was investigated in six populations of Macrozamia, including two populations of M. parcifolia, three populations of M. pauli-guilielmi and one population of M. crassifolia from Queensland (Australia) in order to measure the levels of genetic variation. This was required to establish whether the allozyme data supports recent taxonomic treatment. Seven loci were found to be monomorphic. All species were genetically depauperate, with low levels of genetic diversity (P=17.6–35.3%,A=1.2–1.4,H e =0.02–0.11) compared with two (only) existing reports, and plants in general. Genetic differentiation among populations was high (G ST=0.47). UPGMA cluster analysis using Nei unbiased genetic distance showed M. parcifolia and M. pauli-guilielmi to be more similar genetically to each other than either is to M. crassifolia. This is concordant with groupings based on morphological characters, thus supporting the objectives of the investigation.