Chloroplast DNA analysis of Tunisian cork oak populations (Quercus suber L.): sequence variations and molecular evolution of the trnL (UAA)-trnF (GAA) region.
Sequences of the trnL-trnF spacer and combined trnL-trnF region in chloroplast DNA of cork oak (Quercus suber L.) were analyzed to detect polymorphisms and to elucidate molecular evolution and demographic history. The aligned sequences varied in length and nucleotide composition. The overall ratio of transition/transversion (ti/tv) of 0.724 for the intergenic spacer and 0.258 for the pooled sequences were estimated, and indicated that transversions are more frequent than transitions. The molecular evolution and demographic history of Q. suber were investigated. Neutrality tests (Tajima's D and Fu and Li) ruled out the null hypothesis of a strictly neutral model, and Fu's Fs and Ramos-Onsins and Rozas' R2 confirmed the recent expansion of cork oak trees, validating its persistency in North Africa since the last glaciation during the Quaternary. The observed uni-modal mismatch distribution and the Harpending's raggedness index confirmed the demographic history model for cork oak. A phylogenetic dendrogram showed that the distribution of Q. suber trees occurs independently of geographical origin, the relief of the population site, and the bioclimatic stages. The molecular history and cytoplasmic diversity suggest that in situ and ex situ conservation strategies can be recommended for preserving landscape value and facing predictable future climatic changes.
Université de Tunis El Manar, Faculté des Sciences de Tunis, Laboratoire de Génétique Moléculaire, Immunologie et Biotechnologie LR99ES12, Campus Universitaire Farhat Hached El Manar, Tunis, Tunisie.
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Abdessamad
Université de Tunis El Manar, Faculté des Sciences de Tunis, Laboratoire de Génétique Moléculaire, Immunologie et Biotechnologie LR99ES12, Campus Universitaire Farhat Hached El Manar, Tunis, Tunisie.
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Baraket
Université de Tunis El Manar, Faculté des Sciences de Tunis, Laboratoire de Génétique Moléculaire, Immunologie et Biotechnologie LR99ES12, Campus Universitaire Farhat Hached El Manar, Tunis, Tunisie.
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Sakka
Laboratoire d'Écologie Forestière, Institut National de Recherche en Génie Rural Eaux et Forêts, Ariana, Tunisie.
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Ammari
Laboratoire d'Écologie Forestière, Institut National de Recherche en Génie Rural Eaux et Forêts, Ariana, Tunisie.
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Ksontini
Université de Tunis El Manar, Faculté des Sciences de Tunis, Laboratoire de Génétique Moléculaire, Immunologie et Biotechnologie LR99ES12, Campus Universitaire Farhat Hached El Manar, Tunis, Tunisie Amel.SalhiHannachi@fsb.rnu.tn.
A Salhi
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Hannachi
D057231:Climate Change; D018742:DNA, Chloroplast / Q000235:genetics*; D021901:DNA, Intergenic / Q000235:genetics*; D019143:Evolution, Molecular; D005828:Genetics, Population; D010802:Phylogeny; D029963:Quercus / Q000235:genetics*; D014416:Tunisia
D018742:DNA, Chloroplast; D021901:DNA, Intergenic