tailieunhanh - Báo cáo khoa học: "Gene diversity in natural populations of oak species"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Gene diversity in natural populations of oak species. | Ann Sci For 1993 50 Suppl 1 186s-202s Elsevier INRA 186s Review article Gene diversity in natural populations of oak species A Kremer RJ Petit INRA laboratoire de génétlque et d amelioration des arbres forestiers BP 45 33610 Gazinet Cestas France Summary This contribution reviews studies of nuclear and organelle gene diversity in oak species. Studies of allozymes were reported for 33 species belonging to the sections Erythrobalanus Lepidobalanus and Mesobalanus of the genus Quercus. The extent and organization of gene diversity were investigated at 3 hierarchical levels complex species and population. Total diversity at the species and population level varies greatly among species from to . The range of variation among species is as large as that observed in other plant genera. Life history characteristics and evolutionary history are the main explanations for these results. Species with large and continuous distributions such as o petraea and Q rubra exhibit high levels of gene diversity. Within a complex most of the nuclear gene diversity is distributed within populations 74 . The remaining diversity is mainly due to species differentiation 23 while the between-population component is low 3 . Organelle gene diversity has been investigated recently in 2 species complexes in the section Lepidobalanus one in North America and one in Europe . Compared to nuclear genes organelle gene diversity is strikingly different. Contributions of within-stand variation species differentiation and population differentiation to total diversity are respectively 13 11 and 76 . Trees of a given population generally share the same chloroplast genome. Moreover trees of different species with reported introgression occupying the same stand exhibit a high degree of similarity. Quercusl nuclear gene diversity I organelle gene diversity gene differentiation Resume Diversité génétique dans les populations de chênes. Cette contribution présente une synthèse des résultats obtenus sur