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|Title:||Somatic mutations contribute to genotypic diversity in sterile and fertile populations of the threatened shrub, 'Grevillea rhizomatosa' (Proteaceae)||Contributor(s):||Gross, Caroline L (author) ; Nelson, Penelope (author); Haddadchi, Azadeh (author); Fatemi, Mohammad (author)||Publication Date:||2012||Open Access:||Yes||DOI:||10.1093/aob/mcr283||Handle Link:||https://hdl.handle.net/1959.11/11974||Abstract:||Background and Aims: 'Grevillea rhizomatosa' is a spreading shrub which exhibits multiple breeding strategies within a narrow area in the fire-prone heathlands of eastern Australia. Reproductive strategies include self-compatibility, self-incompatibility and clonality (with and without sterility). The close proximity of contrasting breeding systems provides an opportunity to explore the evolution of sterility and to compare and contrast the origins of genotypic diversity (recombinant or somatic) against degrees of sexual expression. Methods: ISSR markers for 120 band positions (putative loci) were used to compare genetic diversity among five populations at a macro-scale of 5 m between samples (n = 244 shrubs), and at a micro-scale of nearest neighbours for all plants in five 25-m² quadrats with contrasting fertilities (n = 162 shrubs). Nearest-neighbour sampling included several clusters of connected ramets. Matrix incompatibility (MIC) analyses were used to evaluate the relative contribution of recombination and somatic mutation to genotype diversity. Key Results: High levels of genotypic diversity were found in all populations regardless of fertilities (fertile populations, G/N ≥ 0.94; sterile populations, G/N ≥ 0.97) and most sterile populations had a unique genetic profile. Somatic mutations were detected along connected ramets in ten out of 42 ramet clusters. MIC analyses showed that somatic mutations have contributed to diversity in all populations and particularly so in sterile populations. Conclusions: Somatic mutations contribute significantly to gene diversity in sterile populations of 'Grevillea rhizomatosa', the accumulation of which is the likely cause of male and female sterility. High levels of genetic diversity therefore may not always be synonymous with sexual fitness and genetic health. We hypothesize that frequent fires drive selection for clonal reproduction, at the cost of flowering such that sexual functions are not maintained through selection, and the build-up of somatic mutations in meristems results in high genotype diversity at the cost of pollen and ovule fertilities.||Publication Type:||Journal Article||Source of Publication:||Annals of Botany, 109(2), p. 331-342||Publisher:||Oxford University Press||Place of Publication:||London, United Kingdom||ISSN:||1095-8290
|Field of Research (FOR):||050202 Conservation and Biodiversity||Socio-Economic Outcome Codes:||960505 Ecosystem Assessment and Management of Forest and Woodlands Environments||Peer Reviewed:||Yes||HERDC Category Description:||C1 Refereed Article in a Scholarly Journal||Statistics to Oct 2018:||Visitors: 261
|Appears in Collections:||Journal Article|
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