Da. Steane et al., CHLOROPLAST DNA POLYMORPHISM SIGNALS COMPLEX INTERSPECIFIC INTERACTIONS IN EUCALYPTUS (MYRTACEAE), Australian systematic botany, 11(1), 1998, pp. 25-40
Variation in the chloroplast genome of 44 accessions representing 14 E
ucalyptus L'Her. species from the series Viminales (sensu Pryor and Jo
hnson 1971) was investigated. Southern analysis of the chloroplast gen
omes restricted with 12 enzymes revealed 20 restriction-site polymorph
isms of which 7 were autapomorphic to individual trees. The 13 informa
tive restriction-site polymorphisms were distributed between individua
ls of different species, but none was species-specific. Fourteen chlor
oplast haplotypes were identified for south-eastern Australian individ
uals. In endemic Tasmanian species, five haplotypes were identified. C
hloroplast haplotypes appear to have a mosaic distribution in south-ea
stern Australia, more closely associated with geographical regions tha
n with morphological species boundaries. The biogeographic distributio
n of chloroplast haplotypes may be explained by a combination of inter
specific hybridisation and introgression, and convergent evolution. Th
e lack of species-specificity of cpDNA variation indicates that, altho
ugh cpDNA is not appropriate for species-level phylogeny analysis in t
he series Viminales, it may provide useful information in studies of b
iogeography and gene flow in Eucalyptus.