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Updated: Jan 22, 2026

An Allele-specific Gene Expression Assay to Test the Functional Basis of Genetic Associations
Published on: November 3, 2010
Genetic Diversity and Population Structure of Tunisian Festuca Arundinacea Schreb. Revealed by Functional Gene-Based
Hala Chadded1, Karim Guenni1, Manna Crespan2
1Faculté des Sciences de Tunis, Laboratoire de Génétique Moléculaire, Immunologie et Biotechnologie (LR99ES12), Université de Tunis El Manar, Campus Universitaire Farhat Hached, 2092, El Manar, Tunis, Tunisia.
Abstract:
Tall fescue (Festuca arundinacea Schreb.), taxonomically synonymous with Lolium arundinaceum (Schreb.) Darbysh., is a cool-season perennial grass valued for adaptability, forage quality, and stress tolerance. This study evaluated the genetic diversity and population structure of 32 Tunisian spontaneous populations and 3 local varieties using CAAT-box Derived Polymorphism (CBDP) and Conserved DNA-Derived Polymorphism (CDDP) markers. Out of 16 tested primers (8 CBDP and 8 CDDP), 12 (7 CBDP and 5 CDDP) generated reproducible and polymorphic banding patterns, producing a total of 124 bands for CBDP and 121 bands for CDDP. High polymorphism was observed (86.29% for CBDP; 74.38% for CDDP), with a mean polymorphism information content (PIC) of 0.378, confirming the informativeness of both marker systems. Clustering analyses based on CBDP, CDDP, and combined data revealed some grouping tendencies among populations, but these groupings were not strictly associated with geographic origin, bioclimatic stage, or whether populations were spontaneous or cultivated. STRUCTURE analysis suggested two clusters for each marker system, but accessions showed overlapping membership, indicating weak population structure. The combined dataset detected four admixed groups, yet all populations displayed high admixture, reflecting high genetic diversity and extensive gene flow in this outcrossing species. Analysis of molecular variance (AMOVA) indicated that over 97% of the total genetic variation occurred within regions, while PhiPT values were low but significant (P = 0.004). No isolation by distance was detected with the Mantel test (CBDP: r = 0.011, p = 0.419; CDDP: r = 0.087, p = 0.078). This study is the first to apply CBDP and CDDP markers in Tunisian tall fescue populations, demonstrating their efficiency in revealing genetic diversity. The findings highlight substantial genetic diversity among populations within regions and underscore the value of this germplasm for breeding and conservation efforts.
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