Sale-et-al-AusJBot1996.pdf (632.27 kB)
Molecular differentiation within and between Eucalyptus risdonii, E. amygdalina and their hybrids using RAPD markers
journal contribution
posted on 2023-05-16, 10:09 authored by Sale, MM, Bradley PottsBradley Potts, Adrian WestAdrian West, James ReidJames ReidRandom amplified polymorphic DNA (RAPD) studies of a natural hybrid swarm between Eucalyptus amygdalina Labill. and E. risdonii Hook.f. and nearby allopatric stands revealed that, despite clear morphological differences, all bands were shared between species. However, frequency differences revealed genetic divergence between species, populations within species, and individuals within populations. Variation was greatest between individuals within populations and lowest between species. For both species, the direction of variation which distinguished the two populations was in a different direction to that which separated the two species, suggesting population differences were not due to introgression but were the result of genetic isolation and/or strong localised selection. Several morphologically typical individuals with intermediate RAPD profiles were detected in the hybrid swarm and nearby allopatric samples of both species, suggesting that some cryptic introgression may be occurring. Controlled F1 crosses generally had closer genetic affinity to E. risdonii, raising the possibility that some parents used may have been advanced generation hybrids. While natural hybrids selected for their intermediate leaf phenotype were usually also intermediate between the two species using RAPD markers, some deviated markedly toward E. risdonii. The study suggests that morphological appearance does not necessarily reflect genetic (RAPD) status and in some cases detectable RAPD differences between spatially close populations of the same species may be as great or greater than the differences between species.
History
Publication title
Australian Journal of BotanyVolume
44Issue
5Pagination
559-569ISSN
0067-1924Department/School
School of Natural SciencesPublisher
C S I R O PublishingPlace of publication
AustraliaRepository Status
- Restricted