Low isozymic differentiation among five species of the Macrozamia heteromera group (Zamiaceae)

Starch gel electrophoresis was employed to estimate the levels of genetic variation among five entities of the Macrozamia heteromera (Zamiaceae) group which can be recognised on morphological grounds. A total of 168 specimens were assayed for 12 enzyme systems coded by 16 loci. Low levels of genetic variation were observed with 10 of the 17 loci (58%) being monomorphic. Mean percent polymorphic loci (P=26%), number of alleles per locus (A=1.3) and expected heterozygosity (H e=0.06) were all low. Although notably morphologically different, the species are very similar genetically. The overall G st value of 0.10 and the high genetic identity value of (range 0.92–0.97) suggest that these species are either recently evolved or they are depauperate in genetic variation due to inbreeding.