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Title: Molecular ecology and evolution of Ariocarpus Scheidweiler (Cactaceae)
Author: García, Víctor Manuel Rodríguez
Awarding Body: University of Reading
Current Institution: University of Reading
Date of Award: 2011
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Mexico is a centre of diversity for cacti. The predominantly Mexican genus Ariocarpus Scheidweiler, comprises geophytic cacti endemic to the Chihuahuan Desert. Recent authors recognise seven species in the genus, and many infraspecific taxa have been recognised by these and other authors. All the species are threatened. Proficient management of the Ariocarpu5 species genetic resource, with respect to conservation programs, requires a good understanding of the phylogenetic relationships of the genus and its evolutionary history as well as the levels of genetic diversity in-situ and ex-situ, and population genetic structure across natural populations. In this conservation paradigm, the aims of this project were focused on evolutionary and ecological questions, combining sequence data in phylogenetic analysis, and microsatellite markers in population analysis. Employing a Bayesian Concordance Analysis (BCA), seven nuclear microsatellite flanking regions (MFRs) and two chloroplast markers provide an estimation of past events in the evolution of the genus. Results are . suggestive of hybridisation early in evolution of the group. Ten microsatellite loci were amplified across 407 individuals collected from 18 populations representing all seven species of Ariocarpus. Genetic parameters and population structures were described per species. Gene flow between populations and correlation between genetic and geographic distances were calculated when all species data were combined. Results suggest vicariance events playa critical role in the speciation process. The same microsatellite loci were characterized in a putative hybrid. Bayesian cluster analysis showed ongoing natural hybridization between two sympatric species. Eleven microsatellite loci were analysed for two populations of the critically endangered A. bravoanus. Selective removal of plants from natural populations is shown to diminish genetic variability and substructure. The use of ex-situ genetic resources might be considered to improve genetic diversity whenever this material can be allocated to its natural source.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available