Intrapopulation Genome Size Dynamics in Festuca pallens

Abstract

Analysis of double-peaks showed that genome size varied up to 1.188-fold within all 562 seedlings, 1.119-fold within the progeny of a single maternal plant and 1.117-fold in seedlings from grains of a single inflorescence. Generally, genome sizes of seedlings and their mothers were highly correlated. However, in maternal plants with both larger and smaller genomes, genome sizes of seedlings were shifted towards the population median. This was probably due to the frequency of available paternal genomes (pollen grains) in the population. There was a stabilizing selection on genome size during the development of seedlings into adults, which may be important for stabilizing genome size within species. Furthermore, a positive correlation was found between genome size and the development rate of seedlings. A larger genome may therefore provide a competitive advantage, perhaps explaining the higher proportion of plants with larger genomes in the population studied. The reason for the observed variation may be the recent induction of genome size variation, e.g. by activity of retrotransposons, which may be preserved in the long term by the segregation of homeologous chromosomes of different sizes during gametogenesis.

Stabilizing selection on genome size in a population of Festuca pallens under conditions of intensive intraspecific competition

“…The results of our experiments provide clear evidence of stabilizing selection acting on genome size. This study provides experimental support for our previous observations of stabilizing selection in this population, which were based on a discrepancy in the maximum genome size range between the progeny of 17 maternal plants and established plants in the natural population (Šmarda et al. , 2008b).…”

“…The coefficient of variation of the sample and standard peaks averaged 1.57% across 626 measurements within the competition experiments and 1.80% across 282 measurements within the germination experiment (Supporting Information Tables S1, S2). With a similar measurement accuracy using the same instrument and methods, we have repeatedly shown that, in F. pallens (and in this study population in particular), the relative genome sizes as measured using DAPI dye are closely correlated with the absolute DNA content as estimated with propidium iodide; the results are repeatable in different seasons (Šmarda & Bureš, 2006; Šmarda et al. , 2008b), and the differences between samples based on individual measurements agree well with the differences obtained in simultaneous analyses of co‐chopped samples (double peaks; Šmarda et al.…”

“…In the case of the germination experiment, samples were measured when they reached a sufficient size. Measurements were performed using the same instrument and procedures that were used in Šmarda et al. (2007, 2008b).…”

Heavy Metal Pollution, Selection, and Genome Size: The Species of the Žerjav Study Revisited with Flow Cytometry

“…Smarda et al [35] investigated differential seedling survival in a tetraploid Festuca pallens population with up to 1.189-fold genome size variation at constant chromosome number of 2n = 28. In this case, during development of the plants those with the lowest and the highest C-values were eliminated under conditions of intraspecific competition for resources.…”

Speciation on a local geographic scale: the evolution of a rare rock outcrop specialist in Mimulus

“…Â DNA content ( pg) [40]. Additionally, M. filicifolius seeds were pooled with the GB population of M. laciniatus seeds and analysed using FCM to verify genome size differences through analysis of double peaks [41]. Sample and solution preparation and FCM analyses were performed as in McIntyre [42].…”