| Abstract Detail
Recent Topics Posters Suárez-Santiago, Víctor N. [1], Blanca, Gabriel [1], Ruiz-Rejón, Manuel [2], Garrido-Ramos, Manuel A. [2]. Satellite-DNA evolutionary patterns under a complex evolutionary scenario: the case of Acrolophus subgroup (Centaurea L., Compositae) from the western Mediterranean. Here, we test the influence that complex historical processes occurring during speciation exert on the rates of concerted evolution of satellite-DNA. To this end, we have studied the evolution of the sequences of the HinfI satellite-DNA family in a group of plant species with an evolutionary history of recent radiation with recurrent hybridizations, the species of the subgroup Acrolophus (Jacea group, genus Centaurea) from the western Mediterranean area. The HinfI satellite-DNA is conserved in those species and in others belonging to the group Acrocentron of Centaurea and to other related genera of the Centaurinae subtribe (Carthamus and Phonus). The influence of the suggested model for the origin and diversification of the Acrolophus subgroup is evidenced by the existence of three different HinfI satellite-DNA subfamilies coexisting in some genomes, and by the analysis that we have made by comparing site-by-site the transition stages in the process of concerted evolution between the sequences of the each subfamily. The high intraspecific conservation of the repeat units in the external species suggests that the mechanisms producing concerted evolution have been efficient in these taxa. In addition, the comparison of individual nucleotide positions between related species shows a paucity in the spreading of variants in each subfamily with satellite-DNA divergence, an indication of a constant rate of homogenization of the repeated cluster. On the contrary, this trend is absent in the species of the subgroup Acrolophus, which showed similar average sequences, polymorphic sites in each species being scant, most of them autapomorphic, representing early stages of genetic differentiation between species in the process of concerted evolution. The absence of concerted evolution was visualized by similar levels of intraspecific variation and interspecific divergence and by the lack of fixed species-diagnostic nucleotide sites. These facts might reflect the reticulate mode of evolution of Acrolophus.
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1 - University of Granada, Botany, Facultad de CIencias, c/ Severo Ochoa, s/n, Granada, 18071, Spain
2 - University of Granada, Genética, Facultad de CIencias, c/ Severo Ochoa, s/n, Granada, 18071, Spain
Keywords:
satellite-DNA
concerted evolution
Centaurea
Acrolophus subgroup
reticulate evolution
radiation.
Presentation Type: Recent Topics Poster
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P79020
Abstract ID:2628 |
