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Ecological
variants and morphological ecotypes are known in Colophospermum mopane
which suggest phenotypic plasticity and possible genetic differentiation within
the species. Five populations of C. mopane were studied to determine the
levels of allozyme variation within and among them. Average heterozygosity
values at 19 enzyme-coding loci in four populations varied little (H = 1.2% to
2.1%) with a much higher value (6.1%) in the Messina population. Polymorphism
levels were the same for all populations as measured by the average number of
alleles per locus (1.2) and the percentage of polymorphic loci (15.8%).
Pair-wise fixation index (F_ST = 0.001 to 0.004), gene flow (N_em
= 39.840 to 159.840) and genetic distance (D = 0.0002 to 0.0003) values
indicate that four of the populations can be considered a single panmictic
group, but that Messina is sufficiently diverged to regard it as a separate
population. Results are discussed with specific reference to the conservation
of the genetic integrity of C. mopane due to extensive exploitation by
man.

South African Journal of Botany 2003, 69:
282–286