Palaeopolyploidy, Spatial Structure and Conservation Genetics of the Narrow Steppe Plant Vella pseudocytisus subsp. paui (Vellinae, Cruciferae)

Abstract

Allozyme data support the hypothesis of an allotetraploid origin of Vella pseudocytisus subsp. paui that could be representative of other taxa of the core Vellinae group. AFLP data distinguished three geographically distinct groups with no genetic interaction among them. Allotetraploidy and outcrossing reproduction have probably contributed to maintenance of high levels of genetic variability of the populations, whereas habitat fragmentation may have enhanced the high genetic isolation observed among groups. In-situ microgenetic reserves and a selective sampling of germplasm stocks for ex-situ conservation of this taxon are proposed.

Genetic Diversity and Population Structure of Teucrium polium (Lamiaceae) in Tunisia

“…Tetraploid populations clustered into two distinct groups, with bioclimate being the most important factor clearly separating populations. Tetraploids are known for their great ability to adapt to different ecological habitats and to buffer against genetic erosion (Mahy et al 2000;Pérez-Collazos and Catalán 2006).Thus, the tetraploid populations of T. polium that appear to be uniform or morphologically very similar may actually each have a special adaptation to an environment and contain a genetic variation for several genes. Populations 1 and 2 from the subhumid bioclimate had particular bands not found in population 5 from the upper arid area.…”

“…It has been widely applied to assess the genetic structure of diploid and polyploid plant populations (Grundt et al 2004;Guldahl et al 2005;Pérez-Collazos and Catalán 2006). The major limitation of these markers is their dominant nature.…”

Validation of in silico-predicted genic SNPs in white clover (Trifolium repens L.), an outbreeding allopolyploid species

“…), and wild species such as Oxford ragwort (Senecio squalidus) (Brennan et al 2006) and Vella pseudocytisus ssp. paui (Pérez-Collazos and Catalán 2006).…”

Phylogeny and systematics of the western MediterraneanVella pseudocytisus-V. aspera complex (Brassicaceae)

“…It has been hypothesized that the large chromosome base number of the core Vellinae taxa could have originated from ancient paleoploidization events resulting from genome doubling of crosses between diploid ancestors with lower chromosome base numbers (e.g., x = 9 and x = 8; Gómez-Campo, 1981;Crespo et al, 2000;Pérez-Collazos and Catalán, 2006). Using isozymes, Pérez-Collazos and Catalán (2006) demonstrated the allotetraploid nature of Vella pseudocytisus subsp. paui, but could not discern between ancient or recent allopolyploidy.…”

“…A larger number of glacial refugia have been identified/proposed in the warm Mahgrebian and southern Iberian area than in the cold northern Iberian area (Médail and Diadema, 2009), a fact that is reflected in the higher number of plant endemisms occurring in the south (Rodríguez-Sánchez et al, 2008). Though most of the northern Iberian V. pseudocytisus and V. aspera populations are distributed today at altitudes below the estimated distributions of the Pleistocene ice caps, they were probably affected by a severe, cold climate, which probably caused important population bottlenecks (Pérez-Collazos and Catalán, 2006). According to this scenario, it might be plausible that only the better adapted polyploids survived the Quaternary glacial ages in the north, whereas the less adapted diploids were sheltered in the warm refuges of the south, resulting in the present distribution of taxa and cytotypes (Figure 1).…”