engleski

Epigenetic vs. genetic diversity in natural plant populations: a case study of Croatian endemic Salvia species

In plants, epigenetic variations based on DNA methylation are often transmitted across generations. Epigenetic processes may cause significant heritable variation in phenotypic traits without changing the sequence and thus increase considerably the evolutionary potential of plants in response to abiotic and biotic stress. Thus, heritable epigenetic variation could influence the course of evolution in plants, as it can affect the processes of adaptation and divergence through selection of stable epigenetic variants without involvement of genetic variation. In order to understand the true importance of epigenetic processes, existing epigenetic variation of natural plant populations have been assessed and compared to genetic variation. Three Croatian endemic Salvia species including (1) Salvia officinalis L., (2) Salvia brachyodon Vandas, and (3) Salvia x auriculata Mill. have been used as a study system. The species were chosen for having contrasting range sizes and genetic diversity heavily influenced by different phenomena: clonality (S. brachyodon) and interspecies hybridization (S. x auriculata). S. officinalis is widely distributed along the eastern Adriatic coast while S. brachyodon is a stenoendemic plant of a very narrow range size. S. x auriculata is a natural hybrid between S. officinalis and S. fruticosa. Preliminary results based on the analysis of 25 S. officinalis populations showed that the proportion of epigenetic variance attributable to differences among populations was similar to the proportion of the among-population component of genetic variance. Systematic patterns of epigenetic variation were observed in relation to a number of bioclimatic variables related to amount of precipitation at sampling sites. The investigation of clonal S. brachyodon revealed the existence of substantial epigenetic variation among genetically identical plants (clones). Finally, hybrid S. x auriculata exhibited higher epigenetic diversity in comparison to parental species.

epigenetic diversity; genetic diversity; population structure; clonality; interspecies hybridization

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