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Multiple evolutionary processes drive the patterns of genetic differentiation in a forest tree species complex

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posted on 2023-05-17, 14:46 authored by Rebecca JonesRebecca Jones, Dorothy Steane, Lavery, M, Rene VaillancourtRene Vaillancourt, Bradley PottsBradley Potts
Forest trees frequently form species complexes, complicating taxonomic classification and gene pool management. This is certainly the case in Eucalyptus, and well exemplified by the Eucalyptus globulus complex. This ecologically and economically significant complex comprises four taxa (sspp. bicostata, globulus, maidenii, pseudoglobulus) that are geographically and morphologically distinct, but linked by extensive “intergrade” populations. To resolve their genetic affinities, nine microsatellites were used to genotype 1200 trees from throughout the natural range of the complex in Australia, representing 33 morphological core and intergrade populations. There was significant spatial genetic structure (FST = 0.10), but variation was continuous. High genetic diversity in southern ssp. maidenii indicates that this region is the center of origin. Genetic diversity decreases and population differentiation increases with distance from this area, suggesting that drift is a major evolutionary process. Many of the intergrade populations, along with other populations morphologically classified as ssp. pseudoglobulus or ssp. globulus, belong to a “cryptic genetic entity” that is genetically and geographically intermediate between core ssp. bicostata, ssp. maidenii, and ssp. globulus. Geography, rather than morphology, therefore, is the best predictor of overall genetic affinities within the complex and should be used to classify germplasm into management units for conservation and breeding purposes.

History

Publication title

Ecology and Evolution

Pagination

1-17

ISSN

2045-7758

Department/School

School of Natural Sciences

Publisher

John Wiley & Sons Ltd.

Place of publication

United Kingdom

Rights statement

Copyright 2012 The Authors

Repository Status

  • Open

Socio-economic Objectives

Native forests

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    University Of Tasmania

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