Genome size and GC content evolution of Festuca: Ancestral expansion and subsequent reduction

ŠMARDA, Petr, Petr BUREŠ, Lucie HOROVÁ, Bruno FOGGI and Graziano ROSSI. Genome size and GC content evolution of Festuca: Ancestral expansion and subsequent reduction. Annals of Botany. Oxford: Oxford University Press, 2008, vol. 101, No 3, p. 421-433. ISSN 0305-7364.

Basic information

• Original name: Genome size and GC content evolution of Festuca: Ancestral expansion and subsequent reduction
• Name in Czech: Evoluce velikosti genomu a GC obsahu v rodě Festuca: prvotní expanze a následná redukce
• Authors: ŠMARDA, Petr (203 Czech Republic, guarantor), Petr BUREŠ (203 Czech Republic), Lucie HOROVÁ (203 Czech Republic), Bruno FOGGI (380 Italy) and Graziano ROSSI (380 Italy).
• Edition: Annals of Botany, Oxford, Oxford University Press, 2008, 0305-7364.

Other information

• Original language: English
• Type of outcome: Article in a journal
• Field of Study: 10600 1.6 Biological sciences
• Country of publisher: United Kingdom of Great Britain and Northern Ireland
• Confidentiality degree: is not subject to a state or trade secret
• WWW: URL
• Impact factor: Impact factor: 2.755
• RIV identification code: RIV/00216224:14310/08:00024152
• Organization unit: Faculty of Science
• UT WoS: 000253582900009
• Keywords in English: Festuca; fescue; grasses; genome size evolution; chromosome size; base composition; GC content; polyploidy; phylogeny; retrotransposon dynamics; flow cytometry
• Tags: base composition, chromosome size, fescue, Festuca, flow cytometry, GC content, genome size evolution, grasses, phylogeny, polyploidy, retrotransposon dynamics
• Tags: International impact, Reviewed

Abstract

Background and Aims: Plant evolution is well known to be frequently associated with remarkable changes in genome size and composition; however, the knowledge of long-term evolutionary dynamics of these processes still remains very limited. Here a study is made of the fine dynamics of quantitative genome evolution in Festuca (fescue), the largest genus in Poaceae (grasses). Methods: Using flow cytometry (PI, DAPI), measurements were made of DNA content (2C-value), monoploid genome size (Cx-value), average chromosome size (C/n-value) and cytosine + guanine (GC) content of 101 Festuca taxa and 14 of their close relatives. The results were compared with the existing phylogeny based on ITS and trnL-F sequences. Key Results: The divergence of the fescue lineage from related Poeae was predated by about a 2-fold monoploid genome and chromosome size enlargement, and apparent GC content enrichment. The backward reduction of these parameters, running parallel in both main evolutionary lineages of fine-leaved and broad-leaved fescues, appears to diverge among the existing species groups. The most dramatic reductions are associated with the most recently and rapidly evolving groups which, in combination with recent intraspecific genome size variability, indicate that the reduction process is probably ongoing and evolutionarily young. This dynamics may be a consequence of GC-rich retrotransposon proliferation and removal. Polyploids derived from parents with a large genome size and high GC content (mostly allopolyploids) had smaller Cx- and C/n-values and only slightly deviated from parental GC content, whereas polyploids derived from parents with small genome and low GC content (mostly autopolyploids) generally had a markedly increased GC content and slightly higher Cx- and C/n-values. Conclusions: The present study indicates the high potential of general quantitative characters of the genome for understanding the long-term processes of genome evolution, testing evolutionary hypotheses and their usefulness for large-scale genomic projects. Taken together, the results suggest that there is an evolutionary advantage for small genomes in Festuca.

Abstract (in Czech)

Background and Aims: Plant evolution is well known to be frequently associated with remarkable changes in genome size and composition; however, the knowledge of long-term evolutionary dynamics of these processes still remains very limited. Here a study is made of the fine dynamics of quantitative genome evolution in Festuca (fescue), the largest genus in Poaceae (grasses). Methods: Using flow cytometry (PI, DAPI), measurements were made of DNA content (2C-value), monoploid genome size (Cx-value), average chromosome size (C/n-value) and cytosine + guanine (GC) content of 101 Festuca taxa and 14 of their close relatives. The results were compared with the existing phylogeny based on ITS and trnL-F sequences. Key Results: The divergence of the fescue lineage from related Poeae was predated by about a 2-fold monoploid genome and chromosome size enlargement, and apparent GC content enrichment. The backward reduction of these parameters, running parallel in both main evolutionary lineages of fine-leaved and broad-leaved fescues, appears to diverge among the existing species groups. The most dramatic reductions are associated with the most recently and rapidly evolving groups which, in combination with recent intraspecific genome size variability, indicate that the reduction process is probably ongoing and evolutionarily young. This dynamics may be a consequence of GC-rich retrotransposon proliferation and removal. Polyploids derived from parents with a large genome size and high GC content (mostly allopolyploids) had smaller Cx- and C/n-values and only slightly deviated from parental GC content, whereas polyploids derived from parents with small genome and low GC content (mostly autopolyploids) generally had a markedly increased GC content and slightly higher Cx- and C/n-values. Conclusions: The present study indicates the high potential of general quantitative characters of the genome for understanding the long-term processes of genome evolution, testing evolutionary hypotheses and their usefulness for large-scale genomic projects. Taken together, the results suggest that there is an evolutionary advantage for small genomes in Festuca.

Links

• IAA6163303, research and development project: Name: Diverzita vegetace podél gradientu kontinentality na jižní Sibiři: klíč k pochopení raně postglaciální historie střední Evropy

Investor: Academy of Sciences of the Czech Republic, Vegetation diversity along a continentality gradient in southern Siberia: a key to understanding Early Postglacial history of Central Europe

• LC06073, research and development project: Name: Centrum pro výzkum biodiverzity

Investor: Ministry of Education, Youth and Sports of the CR, Biodiversity Research Center

• MSM0021622416, plan (intention): Name: Diverzita biotických společenstev a populací: kauzální analýza variability v prostoru a čase

Investor: Ministry of Education, Youth and Sports of the CR, Diversity of Biotic Communities and Populations: Causal Analysis of variation in space and time